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Organic Pastoral Resource GuideCompiled by Barbara Gillatt and Louise Coats with contributions and assistance from Gavin Kenny, Peter Urich and Bev Trowbridge

Project Manager: Gavin Kenny, Earthwise Consulting Ltd

Illustrated by Fred Robertson, Artmoves Ltd

With contributions from:AgriQuality NZ Ltd, Cedric Backhouse, Kim Baker, Anne Baldock, Hella Bauer-Eden, Kathy Bentham, Bio Dynamic Farming and Gardening Association in NZ (Inc.), Janet Browne, NZ Biological Producers and Consumers Council (Inc.) (BioGro), Ian Buckingham, Lindsay Burton, Rowan Cambie, Malcom & Shirley Campbell, Peggy Cayton, Sue Clark, Dexcel, Joan Dodson, Elise @2farm, George Engeler, Graeme Ewenson, Grant Fallon, Tony Frith, Ian Henderson, Tony Henderson, Mandy Horton, David Johnstone, Fiona Jujnovich, Andrew Knox, Colleen Lamb, Kevin Lamb, Tom Lambie, Ralph Littler, Neil McDonald, Neil Macgregor, Alec MacKay, Rob McKenzie, Mark McIntosh, Helen Macky, Rachel Monk, Andy Moser, George Moss, Mike Moss, NZ Landcare Trust, Alec Olsen, Murray Pedley, Jim and Coralie Peel, Mark and Jane Pike, Maureen Rabbidge, Tom Richardson, Ray and Jenny Ridings, Russell Simmons, John Squire, Heather Stewart, Kevin Thomsen, Alan Thatcher, Tieneke Verkade, John Weissing, Hans Wetendorf

AcknowledgementThis guide is the result of the contributions of many people who freely gave their time and knowledge through workshops, fielddays, reviewing of the different drafts, and providing written material: your input is greatly appreciated. Special thanks are also due to Simon Browne and David Wright for their support throughout the project, John Ridout and the members of the project review team, Kevin Steel, Sustainable Farming Fund manager and Rachel Monk, MAF Policy Hastings. Thanks also to Peggy Cayton and Tom Richardson for your input to running the workshops and to Russell Simmons for your contributions. Thanks to all those who helped with the consultation process during the life of this project.

This publication has been made possible through funding from the Sustainable Farming Fund

Organic Pastoral Resource Guide

ISBN 0-476-00124-2

Published in November 2003 by the Soil and Health Association of NZ Inc. and Bio Dynamic Farming and Gardening Association in NZ Inc.

Copyright: This publication is copyright and remains the intellectual property of the Soil and Health and The Biodynamic Gardening and Farming Associations, Barbara Gillatt, Louise Coats and Fred Robertson. Copying for personal use is welcome subject to the appropriate acknowledgement of source.MAF disclaimer: This research was undertaken by The Soil and Health Association of NZ Inc and the Bio Dynamic Farming and Gardening Association in NZ Inc under contract to MAF Sustainable Farming Fund.Every effort has been made to ensure the information in this report is accurate. MAF Sustainable Farming Fund does not accept any responsibility or liability whatsoever for any error of fact, omission, interpretation or opinion which may be present, however it may have occurred.

Compiler and publisher disclaimer: The information here presented is supplied in good faith. Sources are diverse, often subjective or ongoing research. The compilers and publishers do not accept any responsibility or liability for any application of this resource material. It is the responsibility of the reader to ensure the appropriateness and safety of any course of action.

ContentsPreface 5

Introduction 6What does one see on an ideal organic pastoral farm? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6How is this achieved? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6What this Resource Guide is . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7How to use the Resource Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8A note on the distinction between organic and biodynamic agriculture . . . . . . . . . . . . . . . . 8

The Soil 9What is soil? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Introducing the soil microorganisms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11The soil food web . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Some practical soil chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17A crash course in chemistry! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Soil test reports and interpretation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Trace elements or micronutrients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36Putting the theory into practice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39Biodynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Composting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46Compost tea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50Brix % . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51Effluent as a fertiliser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52Seaweed and fish fertilisers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53Vermicast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54Rock dust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57Paramagnetic material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57Pesticides, herbicides and fertilisers, and the effects on soil . . . . . . . . . . . . . . . . . . . . . . . . 59Salt based fertilisers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59Tools of the trade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Animal Health 62Animal health and stock management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Stock management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64Fibre content of a ruminant diet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

General tools for animal health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66Animal remedies laws: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67Homoeopathy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67Herbal medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69Cider vinegar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73Colloidal silver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Specific Health Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 751. Calf management and worms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 752. Trace element deficiencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 793. Mastitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 844. Lice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 885. Ticks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 896. Bloat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 907. Facial eczema . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 918. Milk fever (Hypocalcaemia) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 939. Grass staggers (Hypomagnesaemia) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9510. Infertility. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9611. Calving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9912. Lameness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10113. Ketosis (acetonemia or acidosis) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10314. Black leg (Entero–toxaemia) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10315. Salt Poisoning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

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PrefaceIn the first half of 2001 a successful application to the Sustainable Farming Fund was made on behalf

of the Bio Dynamic and Soil and Health Associations. The project aim was to draw on the knowledge

and experience of established organic and biodynamic producers and make it more widely available.

The first step was to identify key sectors where we felt the project would make a difference and involve

experienced organic people associated with those sectors who were keen to contribute. As a result

we focused the project on: Dairy/Pastoral Farming; and Avocado, Citrus and Summerfruit production.

Successful organic producers are pioneers, as they acknowledge that there are always more ques-

tions than answers and thus are continually taking on new challenges. That capacity to take on new

challenges has been very evident in this project. Individuals have taken on multiple challenges; they

have acted as workshop facilitators, field day organisers and presenters, and have written and collated

material for a series of Resource Guides. Many others have contributed through their participation at

workshops and field-days, by acting as reviewers and giving their time to make written contributions.

This Resource Guide is a result of that work.

It is important to be clear as to what this Resource Guide isn’t and what it is. It isn’t a detailed technical

‘how to’ document, as there is no simple prescribed pathway towards successful organic production

and there are still many more questions than answers. It is a number of things. First and foremost it

is a multi-authored collation of existing knowledge, presented from a practical perspective. Second,

there has been a deliberate weaving together of organic and biodynamic information. The purpose

of weaving together a range of views is to provide you with choice - take what is relevant to you at

any given time and ignore what you don’t consider to be relevant. Third, it is intended to be a ‘living

resource’. We’ve drawn together what is known to help you avoid making the mistakes that others

have and achieve success more quickly, and also to allow for clearer identification of gaps in knowledge

so that these can be addressed. In summary, this document won’t make you a good organic producer,

it is not a technical ‘how to’ manual, it is intended to be a practical, living, Resource Guide. It is meant

to guide, not to prescribe.

Gavin Kenny, Earthwise Consulting LtdProject ManagerTel: 06 8708 466, Email: [email protected]

August 2003

Avocado, Citrus, Pastoral and Summerfruit Resource Guides are available from the Project

Manager (telephone 06 8708 466 or email [email protected]) or in Adobe Acrobat

(.pdf) format from www.organicnz.org and www.biodynamic.org.nz.

16. Pink Eye (conjunctivitis) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10417. Woody Tongue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10418. Wounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10419. Shock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10520. Drying off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10521. Udder Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10522. Ringworm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10523. Catarrh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10524. Cow pox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10525. Pneumonia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10626. Leptospirosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10627. General tonic for rundown cows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10628. General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

The Environment 108Some thoughts on layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109Moon and planets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109Climate and weather . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110Government and dairy regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111Pasture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111Seeds sourcing and selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118Herbal ley mixtures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119Kikuyu information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123Cropping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125Weeds and their management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126Fallowing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130Trees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131Wetlands and waterways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143Reusing dairy effluent – some methods and tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146Breeding: dairy, beef and sheep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149Breeding and livestock management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150Comments from farmers and practitioners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151Conversion issues for livestock management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153Behaviour: cattle, deer and goats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156Be nice to your cows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157Quarantine paddocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158Minimise contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

Appendix 1: Trees for shelter & profit 162

Appendix 2: Certification & sources of information 164

Appendix 3: Research & case studies 168

Appendix 4: Milli–eqivalents 169

Appendix 5: Parts per million 169

Appendix 6: Observing your clovers and legumes 170

Appendix 7: General resources 170

Appendix 8: aramagnetic values of various elements found in rock 172

Index 173

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Organic Pastoral RESOURCE GUIDE

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IntroductionWhat does one see on an ideal organic pastoral farm?

When one first walks onto the farm, it has a feel of its own, of strength and balance.

The animals are healthy and contented. There are shade and shelter trees at various stages of growth scattered over the farm to protect the animals. There may even be herbal leys under the trees so the animals can graze them.

The grass is a clover and rye, plus mixed herbage, including other species such as plantain, subterranean clover, cocksfoot, chicory, timothy, etc. It is deep green and holds its own longer during a drought, and comes away again quickly when the rains come again. There may even be crops and silage when and where it is needed. The grass, at times, may not appear to be long or bulky, however the energy levels tend to be more concentrated and balanced in nutrients, and the animals seem content.

Of course all this strength is coming from the soil beneath. If you put your spade in the soil, dig up a soil profile, and begin to look carefully, many small but important aspects begin to appear. Firstly you can see and sense a jam packed mass of life in a world of its own, with enzymes, microbes, fungi, algae, arthropods and bacteria, all interacting to produce the necessary elements for a healthy soil. There will be evidence of earthworm activity throughout the profile. The soil will show a deep humus texture at the top, roots that reach right down into the subsoil and no clearly defined line separating the humus and subsoil. It will show a mixing of colours and soils instead. We, as farmers can add elements such as liquid fertiliser, lime and RPR, to help this process. The topsoil is a healthy depth and growing each year, the soil is breathing, and there is no litter on the top of the ground thanks to those worms and enzymes. The number of worms will keep increasing each year.

Because the soil is healthy, alive and balanced, the grass in turn is balanced and healthy, which makes for healthy animals, and in turn, a healthy, life-giving product for the consumer.

How is this achieved?Over the last few decades all farmers have become more aware of the need to become more sustainable on the farm. This has led to greater efficiency, for example, through better use of chemicals and other management tools. In so doing, many have taken the first step towards sustainable farming. This can be called the efficiency step.

The next step is substitution The basics are a commitment to not relying on pesticides, chemical fertilisers or drugs for the animals. Also underlying the whole procedure is the aim of getting the soil active and balanced, and creating an interactive ecosystem. The rest then tends to follow. Basic requirements are lateral thinking plus the ability to make good observations. A good conventional farmer will make a good organic farmer. Many farmers begin slowly and take one aspect at a time, for example using fish fertiliser or homoeopathy, trying other things once they are comfortable to do so. They join a discussion group, or find a mentor, or an email network to keep in touch with others. There are many methods around and many farmers use a combination as to what suits them. The reality is that things are never perfect and we are always learning.

You then your operation. You resolve the problems not through efficiency or substitution but by looking at why they are there and how you can work with nature. You look to create a healthy environment and you look at your farm in the context of the whole ecosystem. If you thought it was a big step to become organic, when you get to the redesign stage you will find it is an even bigger step (or leap) to develop a whole farm system approach. Some people find that substitution is as far as they wish to proceed and they can still be certified organic producers and are happy to remain at that stage. There are models and support networks available for those interested in moving to the redesign stage: two of these include biodynamics and farm forestry.

A warning: however, it is not possible to eradicate all animal health problems on a dairy farm due to simply pushing nature outside its boundaries a bit. Some also believe it is unavoidable to lose some production under this regime, but not neces-

sarily lose profitability. This concept will be challenged in the future. Regardless of which stage you are at, crises will occur from time to time. These are there to challenge us. The important thing to remember is that making good observations and attending to detail is very important to ensure immediate action. Once committed to organics, there are no crutches to fall on, so building a resilient system is the key.

This Resource Guide will give you some answers to the many questions you may have, and will no doubt lead you to asking many more questions.

Please Note

It is the responsibility of the user to check that products used meet any requirement that may be set for products under the Animal Products and ACVM Act administered by NZFSA. Be aware that food safety and residue standards may change from time to time and it is your responsibility to remain up-to-date.

At all times, we must remember our obligations to provide the five freedoms under the Animal Welfare Act Code of Practice:

1. proper and sufficient food and water

2. adequate shelter

3. the opportunity to display normal patterns of behaviour

4. appropriate physical handling

5. protection from, and rapid diagnosis of injury and disease. See page 63.

What this Resource Guide isThe design and content of this Resource Guide has been shaped by the experiences of practicing organic farmers. It has three main chapters: Soil, Animal Health and the Environment. These three chapters relate to the progression experienced by many who have converted to organic farming but it is not a recipe for organic farming. Rather it provides a range of options and ideas for you to choose from.

Objectives to keep in mind when using the Resource GuideFour objectives to keep in mind when using the Resource Guide:

• soils: get the soil alive with earthworms and other microorganisms and balance the soil minerals

• livestock: keep livestock comfortable (sheltered from the extremes in weather), with constant access to cool, clean water, healthy and fed a balanced diet using high quality feeds with health promoting extras. Remember the health and welfare of the animal is paramount

• pasture/crops: produce a quality pasture/crop which is not bothered by insects and provides a complete livestock nutrient source which results in high yields

• biological farming: work with the systems of nature to develop a farm which is environmentally sound and which leaves the land, water, plants and animals in a healthy, productive state for all future generations.

The pathway to successThere are two key ingredients to being a successful organic pastoral farmer:

1) Access to information – this Resource Guide provides you with a start

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2) Support from others. You can achieve this by:

• Joining an organic discussion and support group can be a big help. This

enables you to have support, especially through the transition period.Once

you have some experience, this will in turn help support others in the group.

• If there is no discussion group in your area, try and get one going, even if it

is only two or three people.

• If this is not possible, find yourself a mentor that you can phone and visit

when you need to.

How to use the Resource GuideBecause this Resource Guide is ‘meant to guide not prescribe’ there is no set way to use it to your best advantage. However, there are a few important things that might help you on the way:

1) Start with the soil. Both organic and conventional farmers who reviewed drafts of the Resource Guide have commented on how much they’ve gained from the Soil chapter. This is where good, sustainable, organic management begins. We recommend that you take the time to read this chapter as it will provide you with a good foundation.

2) Find what you need. Most of the time you will use this as a reference when you need relevant information. The Contents will guide you to the main topics that are covered in each chapter. There is also an Index at the back for specific subjects.

3) Look at your options. We’ve given as much information as we can all the way through to provide you with options. What works for others may not work for you. If you can’t find the answers to the questions that you have, this is where support networks become important. We’ve given contact details for relevant people and organisations as much as possible.

4) Keep an open mind. If something doesn’t work for you now, it doesn’t mean that it won’t work in the future. So, find what works for you in the present but also keep your options open for the future because when you enter into an organic system you are entering into something that is dynamic and changing all the time.

A note on the distinction between organic and biodynamic agriculture

Organic agriculture is based on the pioneering work of the likes of Sir Albert Howard and Lady Eve Balfour in the UK and J.I. Rodale in the USA. Its emphasis is that healthy soil is the foundation for healthy food and healthy people. Biodynamic agriculture is founded on the work of Rudolf Steiner who gave a series of lectures to farmers in 1924. It encompasses the basic principles of organics but also works with interactions between the cosmos and earth.

For a more in-depth background the following are recommended readings:Fukuoka, Masanobu. 1978. The One Straw Revolution. Rodale Press, Emmaus, Pennsylvania.

Howard, Sir Albert. 1943. An Agricultural Testament. Oxford University Press, New York and London.

King, F.H. 1911. Farmers of Forty Centuries. Rodale Press, Emmaus, Pennsylvania.

Mollison, Bill and Holmgren, David. 1982. Permaculture One: A perennial agriculture for human settlements. Tagari Publications, Stanley, Tasmania.

Steiner, Rudolf. 1993. Agriculture. Biodynamic Farming and Gardening Association Inc., Kimberton, Pennsylvania.

The Soil• Consists of mineral, water, air, organic matter and microorganisms

• Each individual group of soil microorganism has a definite role in the soil

• Organic matter drives a soil system

• Soil compaction problems can result from the loss of soil microorganisms after pugging and long-term water saturation

As part of this project

there is an associated

email discussion

group for sharing

information and

experiences. To join

the group, send an

email to Peter Urich

([email protected])

expressing interest in

the group and you will

be subscribed.

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What is soil?We walk on it every day. We drive over it. We dig in it but do we really know what it consists of? We will have to have a brief review of what ‘soil’ is so that we have some appreciation as to what we are farming with. Then we can begin to appreciate some of the profound effects that some of our day to day practices do to our soil.

Introducing the soil microorganismsFarmers are in fact farming all the small and, most commonly, microscopic organisms in their soil, and a farmer will have far more livestock in the soil than he will ever have in the four legged variety walking upon it. It is the fact that most of this underground ‘livestock’ is not readily visible to the naked eye that the farmer seldom realises the adverse effects some farming practices have on ‘underground livestock’.

The soil should consist of the following - minerals, organic matter, water and air in the approximate ratios listed below.

• Minerals – about 45%

• Water – about 25%

• Air – about 25%

• Organic matter and living microorganisms – about 1 to 5%

MineralThe mineral portion has originally come from weathered rock (the ‘parent material’). Rock is weathered by the elements like rain, ice and rockslides until the parent material is broken into smaller pieces. These rock particles are carried by rain or wind, and are further worked on by acids secreted by microor-ganisms and roots of plants, trees etc., so eventually the rock is broken down into elements that can be used by all living beings, whether it is a plant, an animal or human. These minerals are recycled and they eventually end up in the sea or on low lying parts of the land where they settle and are compressed and end up being rocks again which eventually can be moved around by the forces of nature like earthquakes and volcanoes.

WaterWater in the soil is very important because it dissolves and carries nutrients and other materials inside the plant and in the soil. The amount of water a soil can hold (amount available for plants) depends on soil type. Sandy soils have low total pore space, but the water that is present can be readily used by plants. Clay soils have greater pore space and hold much more plant available water than sands. Water and air make up, on average, 50% of the space in the soil (the range can be 30 to 75%). These water and air filled spaces are called soil pores. In a well-drained soil of moderate moisture about half the pore space will be filled with water and half with air. In a waterlogged soil most of the soil pores will be filled with water, starving soil microorganisms of air. These soils also take a long time to warm up and microbes will be slower to act.

AirAir in the soil is essential for plant health. Good soils need to be aerated and in fact, although it may be hard to believe, the soil should be able to function like a lung. Everyone knows that there is always movement of air from a region of high pressure to a region of low pressure. Changing barometric pressure influences the movement of air into and out of the soil, which enables the soil to breathe – the lung effect. Oxygen is essential for biological activity. Most of the beneficial soil organisms require oxygen (the term is aerobic). If you have a very dense soil, a compacted soil, or if the soil is waterlogged, you have a lack of oxygen and the term is anaerobic. Under anaerobic conditions we can have undesirable bacteria domi-nating in action that can cause problems by releasing nitrogen and even toxic by-products such as hydrogen sulphide, methane and nitrous oxide into the air. These stressors may later lead to pasture or crops being affected by diseases and pest attack.

Organic matterWhat is ‘organic matter’? Organic matter is a food source for all those organisms in the soil and consists of the follow classes:

• Living organisms• Fresh organic matter• Decomposing organic matter• Humus.

Living organisms include: bacteria, fungi, algae, nematodes, protozoa, earthworms, arthropods and living roots.

Fresh organic matter consists of: dead plant material; organic material; detritus; and surface residue. All these terms refer to plant, animal or other organic substances that have recently been added to the soil and have only begun to show signs of decay. There are organisms that feed on this material and they are called detritivores.

Decomposing matter has: an active fraction of organic matter; labile organic matter; root exudates; lignin.

The active fraction of organic matter consists of organic compounds that can be used as food by microorganisms. The active fraction changes more quickly than total organic matter in response to management changes.

The labile organic matter is that which is very easily decom-posed and is typically used by bacteria and a limited set of fungi, particularly yeasts.

Root exudates are the soluble sugars, amino acids, enzymes (these break down other foods) and other compounds secreted by roots. Yes, roots actually put food into the soil! This is another quite important concept as most would believe that roots just take minerals and water out of the soil.

Lignin is a structurally complex, highly diverse and therefore hard-to-break-down compound that comes from the break-down and condensation of decomposition of plant litter material. Fungi are just about the only soil organism group that can in fact use the carbon ring structures in lignin as food.

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HumusHumus consists of highly recalcitrant organic matter or humified organic matter. This recalcitrant organic matter is material that few soil organisms can decompose. The humified organic matter consists of complex organic compounds that remain after many organisms have used, condensed and transformed the original material. Humus is not readily decomposed because it is either physically protected inside aggregates or is chemically too complex to be used by most soil organisms.

Humus complexes tiny soil aggregates and it also improves water and nutrient-holding capacity. Humus can be lost by ploughing waterlogged soils or by nitrogen over usage. Ploughing results in the loss of humus as the bacteria have access to the surfaces of more organic matter that has been made available by the soil being cut into bits. The bacteria are stimulated, grow and divide and release carbon dioxide. It has been quoted that for each kg of applied nitrogen used, up to 10 kg of carbon (humus) is lost. As mentioned before, humus has the ability to hold water, and for each kg of humus in the soil 4 kg of water can be held. So, over-use of nitrogenous products can have significant negative impacts on the soil.

The humus region in the soil can be observed by taking a spade to undisturbed soil and digging out a square foot or so. You will notice that there is a darker soil layer that tends to become lighter in colour as depth into the soil increases (approaching the parent soil material). On farms where conventional prac-tices have been replaced with organic techniques it is commonly noticed that this dark zone becomes wider and extends deeper into the soil. This is a good sign.

We have described the term humus but in the course of this Guide you will come across a couple of other terms – humic acid and humates. These are all slightly different materials. Humus is rich in certain large molecules called humic substances, including humic acids, fulvic acids and ulmic acid. Humic acid is derived from humus. It is also present in other organically derived materials like peat or certain soft coal deposits. Which brings us to another term – humates. Brown coal or near coal deposits (humates or leonardite), along with rock layers high in organic matter are ground up and used on agricultural soil. Humates can be used as is, or the humic acids from these deposits can be extracted with alkaline solutions to give liquefied humic acid, which can be applied to the oil or plant as a spray.

We mentioned living organisms before – let’s now define these and see what they do in the soil. When we appreciate what part each of these organisms play in the soil we can then start to appreciate some of the negative impacts our everyday farming practices have on these soil microorganisms. We can also then begin to understand why organic accreditation agencies insist on some of these practices being banned, and why there is an increased interest in sustain-able agriculture in general.

The soil food webInformation in this section is based, in part, on The Soil Biology Primer (see Tugel et al.)

The soil food web includes a group of organisms living all or part of their lives in or on the soil. There is a conversion of energy and nutrients as one organism eats another. Consider what happens to this food web if a product is used and kills out several of the members of the third trophic level. There will be the potential loss of some or all of the fourth and fifth tropic level micro-organisms.

We will now consider the numbers of all the soil inhabitants. What should a teaspoon of healthy agriculture soil have in it?

In 5 grammes (1 gram dry) of healthy agricultural soil we would expect:

bacteria – 100 million to 1 billion - a mass of 1 cow

per hectare!

fungi – several yards

protozoa – several thousand flagellates and

amoebae, 100 to several hundred ciliates

nematodes – 10 to 20 bacterial feeders, a few fungal

feeders. Few predatory nematodes.

In a square spade full of agricultural soil we would want:

arthropods – up to 100

earthworms – 5 to 30 - more in soils with high

organic matter.

These figures might seem astonishing to you but there are laboratories around the world specialising in counting the soil microorganism diversity. Thus, having examined and recorded the count of the various microorganisms from healthy soils growing a certain crop or pasture, they can now give an indication as to where problems lie if the soil is not producing good quality crops or pasture by looking at the ratios, types or absence of the various soil microorganisms.

All food webs are powered by the plants, photosynthetic bacteria, algae, moss and lichens, which harness the sun’s energy to fix carbon dioxide from the air to make amongst other things – sugar. Most of the rest of the soil organisms get their fill and energy by eating organic compounds found in plants and other organisms and from waste products. Nutrients end up cycling along the food pathways and get converted from one

product to another and are then made available to other plants or other organisms.

The soil food web is driven by organic matter. This is the storehouse for energy and the cycling of nutrients. Most soil organisms live wherever organic matter occurs - mainly in the top 7-10 cm of the soil, though they are concentrated around roots, in litter, on the surface of soil aggregates and in the spaces between soil aggregates and some fungi work in humus. Living organisms can be found as deep as 12 miles into the earth’s surface, as evidenced by investigations of deep mines and oil wells. These soil organisms vary in activity during the year but tend to follow a seasonal pattern as well as a daily pattern. Activity is governed by soil temperature, moisture and aeration. Healthy soil will tend to have a more stable overall temperature, moisture and aerobic range compared to an unhealthy soil.

The health of a soil is influenced by the variety of organisms. The greater the biodiversity in soil, the greater the food web complexity. Biodiversity is measured by the total number of species as well as the relative abundance of these species and the number of functional groups of organisms. A complex soil food web that contains many different organisms can compete with disease-causing organisms.

The organisms in the soil retain nutrients in their bodies.

Certain species solubilise nutrients from the parent material of the soil and make those nutrients available to plants directly, while other microbes release nutrients retained in the bodies of their prey groups, again releasing plant available forms of nutrients. Other soil organisms make the air passageways, hallways and pore spaces needed to keep air flow and water flow stable in the soil, preventing erosion and increasing water holding capacity.

So in summary, all plants – grass, trees, shrubs and crops depend on the soil food web for nutrition. The power of the organisms present in healthy soil should never be underesti-mated and can never be replaced with interventions by farmers using solid fertilisers or by using chemicals in an attempt to ‘fix’ problems. Farmers must appreciate this critical interrelationship between microorganisms and successful or failing soil and crop management. Farmers must farm the microorganisms so that the pasture or crop is fed and so that the soil remains ‘alive’. To become better farmers of soil microorganism lets learn a little more detail about each group of inhabitants that should be present in your soil and what each does.

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BacteriaUnfortunately they are so tiny you need a microscope to see these organisms. They consist of a single cell and perform a remarkably broad set of functions. Most of them are not photosynthetic (do not have the ability to make sugar from light) but the photosynthetic cyanobacteria (formerly called blue-green algae) can fix nitrogen as well as fix carbon dioxide into sugars and proteins. Another group of bacteria the acti-nomycetes (now renamed the actinobacteria) give healthy soil its characteristic smell. If the soil has been abused and the proper biology lost, this good earthly smell will no longer be detected.

What do bacteria do?They build soil aggregates at the smallest level, improve water retention in the soil, decompose organic matter, filter and degrade pollutants as water flows through the soil, cycle nutrients, are food for other microorganisms in the soil and protect plant surfaces from disease organisms Some bacteria affect water movement by producing substances that help bind soil particles into small aggregates. These aggregates then improve water infiltration and the soils water-holding capacity. One very important point to remember is that if we have a diverse bacterial community – that is one with many different types of bacteria – the soil community will be able to compete with disease-causing organisms in roots and on above ground surfaces of plants.

Bacteria are very important for the nitrogen cycle in the soil. The three other important groups of bacteria are the nitrogen-fixing bacteria, nitrifying bacteria and denitrifying bacteria.

Nitrogen-fixing bacteria form close (symbiotic) associations with the roots of legumes like clover or lucerne, or may be non-symbiotic such as the azotobacter or azospirillum. If you have unearthed a clover plant you will see visible nodules created where the bacteria have infected a growing root hair. If the nodule is cut in half the interior colour gives an indication as to the state of these bacteria and whether they are fixing nitrogen - a pink colour indicates that they are. The plant supplies simple carbon compounds (sugar) to the bacteria and the bacteria convert nitrogen (N2) from air into a form the plant host can use. When the leaves or roots from the host plant decompose, soil nitrogen increases in the surrounding area.

The nitrifying bacteria change ammonium (NH4+) to nitrite

(NO2-) and then to nitrate (NO3

-), which is a preferred form of nitrogen for grasses and most row crops. Nitrate is the most easily leached form of nitrogen in soil. This form of nitrogen should not be present whenever water is moving in agricultural soil so leaching losses are minimised.

The denitrifying bacteria convert nitrate to nitrogen (N2) or nitrous oxide (N20) gas. Denitrifers require anaerobic condi-tions so you will find these in waterlogged soils or inside soil aggregates where there is little oxygen.

Aerobic bacteria thrive in the ‘rhizosphere’, which is the narrow region in and around plant roots. There is evidence that plants

produce certain types of root exudates (like sugars, proteins and carbohydrates) to encourage the growth of protective bacteria and fungi. Bacteria alter the soil environment to the extent that the soil environment will favour certain plant communities over others. This can be seen when you have waterlogged soil that has been pugged or compacted which selects for ‘weeds’ like willow or pepper. The bacteria in these conditions will tend to be anaerobes, there will be a change in the availability of minerals and conditions will favour the ‘weeds’ over grass species.

Bacteria can be oxygen requiring (aerobic) or oxygen intolerant (anaerobic). Our farming methods should attempt to keep soil in an aerobic state if possible as anaerobic conditions favour the loss of nitrogen as ammonia, sulphur as hydrogen sulphide and the production of low pH organic acids such as vinegar and putriscine. Oxygen cannot travel easily through waterlogged or compacted soil. Bacteria that require reduced oxygen condi-tions to grow are typically detrimental to plant and animal health and can result in the loss of cations from the soil.

FungiThis group is another one that has microscopic cells. Fungal cells form long chains called hyphae. A single hypha can range in length from many metres down to a few cells. These hyphae are only a few micrometers in diameter. Some fungi, such as yeast, are single-celled.

There are fungi called saprophytic fungi that decompose dead organic matter and are commonly active around woody plant residue. Another group are called mycorrhizal fungi and these are a very important group as they form associations with plant roots. This enables the fungi to get energy from the plant (in the form of sugar) and to help supply nutrients (like calcium, sodium, phosphate etc.) to the plant as these fungi forage extensively and their hyphae are like extremely fine cotton threads that form a matrix within the soil and can source minerals the plant needs at some distance away and transfer this to the root hair.

There is evidence that soluble phosphate and nitrogen sources are not that friendly for mycorrhizal fungi and so the number of mycorrhizal fungi decline from the soil, and with this goes the ability of the plant to have access to minerals that are at a distance from the root. Broad spectrum fungicides are also toxic to mycorrhizal fungi. Fungi live in aerobic (needing oxygen) conditions so it is important that the farmer attempts to keep his soil in a condition that allows the soil to breathe. If the soil is waterlogged or compacted (heavy machinery, pugging by cows, incorrect mineral balance – see the cation section later in the Guide) for a significant period of time then generally the soil loses its fungal component. Under dry conditions fungi can bridge gaps between pockets of moisture and continue to survive and grow, even when soil moisture is too low for most bacteria to be active. Fungal hyphae bind soil particles together thus building stable aggregates that improve water-holding capacity. This feature explains why organic farmland tends to hold on longer during a drought and rebound quickly when the

drought breaks. Frequent tillage reduces fungal numbers in the soil. Some inocula of mycorrhizal fungi are commercially available and can be added to the soil at planting time but must come into contact with a root within 24 hours otherwise it will die.

AlgaeAlgae can be either unicellular or complex multicellular plants occurring in moist ground or in fresh or salt water, that have chlorophyll and other pigments so can harvest the energy of sunlight to build sugars (carbohydrates), proteins etc., but lack true stems, roots and leaves. This energy source is so important for the soil system. As this group of plants requires light, water and carbon dioxide for photosynthesis they do not appreciate being sprayed with herbicides. If herbicides are not degraded in the soil (some of the modern ones cannot be broken down), then these herbicides will continue to limit algae numbers which can have serious repercussions for the rest of the food web as an important source of sugar (and other foods) has been lost or reduced.

NematodesThis family of worms are tiny – usually you need a microscope to see these and they are non-segmented. Most of these live free in the soil.

There is a lot of bad press about nematodes as a few cause plant problems (root feeding nematodes graze on the roots of plants and are not free-living in the soil) but the vast number in the soil are in fact highly beneficial. We can have bacterial feeders, fungal feeders, predatory feeders, plant feeders and omnivores who eat a variety of organisms and may have a different diet at each life stage. These nematodes are free-living.

What do these characters do in the soil?The nematodes have many duties in the soil but a key duty is to cycle nutrients. Other duties relate to their activity in the soil. They graze, spread microbes, and also end up being a food source if they are caught and can be involved in disease suppression. It would appear that they are a pretty versatile member of the soil microbe group.

Whenever nematodes eat bacteria or fungi, plant available ammonium ends up being excreted back into the soil as more nitrogen is eaten than is required by the nematode. So you can immediately see that this group of soil microorganisms is an important part of the nitrogen cycle.

Grazing activity by nematodes also influence the bacterial population numbers and can impact negatively on mycorrhizal fungi. Nematodes may be a key in controlling the balance between bacteria and fungi in the soil.

Nematodes can be described as taxi cabs as their movement helps to spread bacteria and fungi in the soil and along plant

roots by carrying live and dormant microbes on their surfaces, and when they excrete their waste from their digestive tracts even more microbes are released.

Nematodes are a source of food for higher level of predators (e.g. predatory nematodes, soil microarthropods and soil insects). They are also parasitised by bacteria and caught by fungi.

Nematodes can consume disease causing organisms or prevent their access to roots. So, in fact, this family have to potential to become biological control agents.

ProtozoaThese are tiny, single-celled animals and include amoebas, ciliates and flagellates. Their presence in the soil is so impor-tant for the nitrogen cycle as they graze on bacteria but get too much nitrogen from them so have to vomit the excess back into the soil in the form of NH4

+. This occurs near the root system

of a plant and either the plant absorbs the ammonium ion or bacteria or other microorganisms use it. One group of amoeba eat fungi by drilling a hole in the hyphae by generating enzymes that eat through the fungal cell wall.

Protozoa also regulate bacterial populations so may influence the numbers of pathogenic (disease causing) bacteria and are themselves a source of food for other soil microorganisms. Those farmers who do spore counting for monitoring facial eczema risk will have seen protozoa swimming across the microscope field.

EarthwormsAt last something that we can see! They do not need intro-ducing. The presence of the earthworm is a good indicator of the health of the soil. A count of 25 per cubic spade of soil indicates excellent soil while below 5 per cubic spade is poor during spring and autumn. Worm populations can be counted by digging out a cube and counting them or by counting their castings on the surface. Note however that not all soils have earthworms yet they may be good, fertile soils. Earthworms are simply rare or absent in some geographical areas – and sandy soils seldom have many.

What do earthworms do? They dramatically alter soil structure, water movement, nutrient dynamics and plant growth. That should be enough reason to encourage them to stay!

Earthworms fragment organic matter and recycle the nutrients it contains. They will drag fallen leaf material into their holes and shred this, which allows bacteria and fungi to grow on the torn leaves (so earthworms stimulate microbial activity). Earthworms then derive their nutrition from grazing on the fungi and bacteria and even possibly protozoa and nematodes. There are however many more microorganisms in earthworm castings or faeces than in the organic matter they consume. This increased microbial activity facilitates the cycling of nutri-ents from organic matter and their conversion into forms readily taken up by plants.

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Earthworms mix and aggregate the soil while they go about their business. They can move large amounts of solid from the lower strata to the surface and carry organic matter down into deeper layers. They have the potential to turn over the top 15cm of soil in 10 to 20 years.

Earthworms enhance the porosity of the soil as they move. Some worms make permanent burrows deep into the soil. These burrows can persist long after the inhabitant has died and can be a major conduit for soil drainage, particularly after heavy rain. At the same time the burrows can minimise surface water erosion. By fragmenting organic matter and increasing soil porosity and aggregation there can be a significant increase

Mineral content of the soil vs earthworm castings

SurfaceNutrient element Soil (0-16cm) worm casts

Total exchange capacity 22 26pH 6.5 7.0Humus % 14 25Nitrate ppm 4 77Ammonium ppm 13 66Total nitrogen ppm 17 143Sulphur ppm 25 29Phosphate(eas. extr)ppm 39 155Phosphate(Bray) ppm 162 253

Potential of Earthworm activity in topsoil (16cm deep) of one hectare

No. worms No. worms Weight of Weight of Weight of Nitrogen/day Nitrogen per N/equiv. ureaper 20 X 20 per hectare worms per worm casts casts/year per ha year per ha per yearcm spade ha in Kg per ha/day Tonnes/ha Kg Tonnes Tonnes

1 250000 165 165 60 2 1 12 500000 330 330 120 3 1 23 750000 495 495 181 5 2 44 1000000 660 660 241 7 2 55 1250000 825 825 301 8 3 66 1500000 990 990 361 10 4 77 1750000 1155 1155 422 12 4 88 2000000 1320 1320 482 13 5 109 2250000 1485 1485 542 15 5 1110 2500000 1650 1650 602 17 6 1211 2750000 1815 1815 662 18 7 1312 3000000 1980 1980 723 20 7 1413 3250000 2145 2145 783 21 8 1614 3500000 2310 2310 843 23 8 1715 3750000 2475 2475 993 25 9 1816 4000000 2640 2640 964 26 10 1917 4250000 2805 2805 1024 28 10 2018 4500000 2970 2970 1084 30 11 2219 4750000 3135 3135 1144 31 11 2320 5000000 3300 3300 1205 33 12 24

The above analysis was by Brookside Laboratories.

ArthropodsHere is another family of soil organisms that can be seen by eye. These are invertebrate animals with jointed legs but no backbone! They include insects, crustaceans, sowbugs, spring-tails, arachnids (spiders), ants, dung beetles, mites, centipedes, millipedes and others.

Most arthropods live on or in the upper 75 mm of the soil. They can be grouped as shredders, predators, herbivores and fungal feeders based on their functions in soil. Arthropods can be present in huge numbers in or on the soil. For each square meter there can be 700 to 250,000 individual arthropods depending upon the soil type, plant community and manage-ment system in place.

What do arthropods do?If you exclude the herbivore group, which feed on plants and can become pests (clover flea, clover weevil), most arthro-pods perform beneficial functions in the soil-plant system. Arthropods shred organic material so that the surface area is increased allowing bacteria and fungi to do their work. These organisms act like can openers and greatly increase the decom-position rate. Arthropods eat decaying plant material to eat the fungi and bacteria on the surface of the organic material. Arthropods stimulate microbial activity, they mix microbes with their food and for bacteria, who have limited mobility being moved to a food source is a good idea. Bacteria are carried on the exoskeleton of the arthropod and through their digestive system.

Arthropods mineralise some of the nutrients in bacteria and fungi and excrete these in plant-available forms. Arthropods enhance soil aggregation by their deposits of faecal pellets, which contain a highly concentrated nutrient resource in a mixture of organic and inorganic substances required for growth of bacteria and fungi. Burrowing done by some of these arthropods exerts a huge influence on the composition of the total fauna by shaping the habitat.

The physical properties of the soil can change, including the porosity, water infiltration rate and bulk density. Arthropods stimulate the succession of species. Soil arthropods consume the dominant organisms and permit other species to take their place thus facilitating the progressive breakdown of soil organic matter.

Arthropods can also control pests. Where a healthy population of predators is present they will be available to deal with a variety of pest outbreaks. To be able to do this there must still be a food source constantly available so it is important for there to be a diverse and healthy food web.

We have now covered all the main soil microorganisms and you will now have an appreciation of the potential diversity the soil on a farm can achieve if we remove or limit some of the damaging practices that are routinely applied to the soil. Here are a few points to ponder:

• Consider what broad spectrum fungicides used for

killing the facial eczema fungus do to the other fungi

in the soil.

If we consider the fungus causing facial eczema

of livestock we could also wonder if the problem

is influenced by the use of soluble phosphates and

nitrogen which causes the loss of the highly benefi-

cial mycorrhizal fungi

• Consider what some of the regular anthelmintics

(drenches) that are given to animals which are then

excreted in either urine or faeces are doing to the

nematodes in the soil.

Again, consider some of the animal drenches like

one that is used for bloat, which is a rumen modifier

and kills protozoa and this too is passed through the

cow and is deposited on to the soil and is believed to

be active for some weeks.

• Consider what insecticides do to all the beneficial

arthropods. Spraying for a clover weevil or clover

flea will kill off many other arthropods resulting in

a declining soil diversity. As this happens predator

arthropod populations decline and the possibility for

subsequent pest outbreaks increase.

• Consider what tillage does to this group of arthro-

pods. Heavy machinery can cause a lot of damage

to soil structure, especially if the soil is very water-

logged.

Some practical soil chemistryWhile the importance of the soil food web can’t be over-emphasized we can’t forget the important role of nutrients in the soil. As we will discuss later, the important role of the farmer is to get the right balance of organisms and nutrients in the different soils (it is not often that you will have only one soil type to deal with) that are being managed on the farm.

Soil nutrient reservesOut of the total reserves (100%) of nutrient elements present in the soil there will be at best only 5% of these which will be exchangeable at any one time. At any time only 0.1% will be readily available (in soil solution) and yet the crop needs 1%. These proportions hold for phosphorous, potassium and magnesium.

One of the major shortfalls of a soil test report is that it is

in the water-holding capacity of soils.

Earthworms provide channels for roots to penetrate deep into the soil and these are already lined with readily available nutri-ents to feed the plant. Earthworms have few enemies in the soil apart from flat worms and a species of parasitic fly but birds and mammals prey upon them at the soil surface. There are quite a number of products applied to soils that can kill earth-worms. Copper sulphate is not very soil microbe friendly and ideally foot-bath fluid should not go into the effluent system as the high concentration of copper will take out a lot of other soil organisms as well. Ammonium sulphate is also very unfriendly to the worm population.

SurfaceNutrient element Soil (0-16cm) worm casts

Calcium ppm 3320 4150Magnesium ppm 250 420Potassium ppm 170 253Sodium ppm 38 39Boron ppm 1 2Iron ppm 49 64Manganese ppm 35 66Copper ppm 7 30Zinc ppm 9 33

The above analysis was by Brookside Laboratories.

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difficult to know for sure in many cases exactly how large the soil’s total or available nutrient supply really is. A soil test generally measures the exchangeable and readily available nutrient elements although one of the phosphorous tests does measure phosphorous reserves. A shortfall of some nutrient elements cannot be measured in a soil report – yet! Though it may be guessed at. You will have to assess the effect that previous crops, green manure crops and the addition of nutri-tional elements by roots and microbial activity will have, and of course there will be the influences of weather and soil structure and so on.

There is also the use of plant analysis to give you a snap shot on how the crop or pasture is coping and if there are any deficiencies in nutrient elements, which can be a useful check. An alternative is to develop skills in using a refractometer and taking Brix readings to monitor changes (see later section).

There is also one other limiting factor for crop and pasture growth which should be covered and that is the effect of a limiting element. The productivity of the soil can never be greater than the plant nutrient in the least supply. The element in least supply will be the crop’s first limiting factor if you consider nutritional factors alone. Another limiting element may also develop and further reduce the potential of your crop or pasture. The crop will never attain its genetic potential, the crop yield will be low and those animals or people who consume it will not fare well.

Lastly we have nutrient interactions or competition between nutrient elements under certain conditions. An excess of one element can cause a deficiency of another element. This is another reason why it is necessary to get a balance of cations and anions in the soil so that there is no chance for an ‘exces-sive element’. Scientists still probably don’t know all of these interactions but here are some examples of ones that have become obvious:

• Excessive potassium, sodium and magnesium can cause a calcium deficiency

• Excessive potassium will depress sodium, iron and manganese

• Excessive nitrogen can depress magnesium and calcium levels

• Excessive nitrogen can tie up copper

• Excessive calcium can cause phosphorus and trace element deficiency (over limed soil is not easy to correct so it is best to never develop this situation)

• Excessive calcium can tie up potassium and manganese

• Excessive phosphorous can depress zinc, iron, calcium, copper, manganese and magnesium

• Excessive iron will depress copper, potassium and phosphorous

• Excessive zinc will depress iron and copper.

One of the major factors influencing nutrient availability is the soil pH as it is the acidity or alkalinity, which determines whether an element is going to be plant available or not. This is why the optimum pH range is often listed as being from pH 6.2 to pH 6.8. If some types of elements are too available they can be toxic to plants such as Aluminium, manganese, boron, copper, cadmium, mercury and chlorine.

The main point to gather here is that any element in excess can have many other influences on the whole soil chemistry system which makes farming with an unbalanced system fraught with potential problems. It is a far easier to move the soil chemistry towards ‘balance’, which requires a good understanding of the role of individual nutrients and how they interact within the whole farm system.

Soil and plant interaction – how does the soil ‘work’?

Plants need the full array of elements that can be made into an available form. They need air, water and sunshine (warmth and light energy).

It is generally stated that 16 elements are required for life processes, to grow, to be healthy and to be able to reproduce. This number may be incorrect as there are plants that need other elements like silicon and nickel. But, we will concentrate on the main 16 elements: oxygen, carbon, hydrogen, nitrogen, potassium, calcium, sulphur, phosphorus, magnesium, manga-nese, iron, zinc, chlorine, boron, copper and molybdenum. One important point to remember is that most of the bulk of the plant that you see comes from carbon dioxide and water.

How much of the plant comes from air and water? 95%

How much of the plant comes from the soil? 5%

Only 5% of the bulk of the plant comes via the soil

from minerals, humus and fertilisers.

This might surprise you. It has implications for when you use green

manure crops like mustard or lupin or even rye and clover. These

crops are grown and turned back into the soil before seeding. This

method is putting a lot of ‘food’ made from the air plus a little that

originally came from the soil back into the soil to improve soil fertility

and feed the microorganisms. One can see instantly that the burning

of stubble is a huge waste. Don’t forget that plants have roots so the

root part of the plant is part of its bulk too. There is almost as much

of a plant underground as there is visible on top of the ground.

Back to our plant. What is the typical composition?

Plant tissue consists of 80 to 90% water – H20 and the other 10 to 20% is the dry matter of the plant. The figures quoted for a typical 16 element content of a plant are:

Oxygen 45.0% Carbon 44.0%Hydrogen 6.0% Nitrogen 2.0%Potassium 1.3% Calcium 0.6%Sulphur 0.3% Phosphorous 0.4%Magnesium 0.25% Manganese 0.05%Iron 0.02% Zinc 0.01%Chlorine 0.01% Boron 0.005%Copper 0.001% Molybdenum 0.0001%

You can see from this list that the main plant elements are carbon, hydrogen and oxygen, making up a total of 95% of the plant.

Plant cells have structures that are able to harness the sun’s

energy and form glucose – a carbohydrate that is made from carbon, oxygen and hydrogen, i.e. carbon dioxide and water.

CO2 + H2O SUNLIGHT (CH2O) + )O2

GREEN PLANTS

This diagram shows that plants take the water and carbon dioxide and in the presence of sunlight can convert this into carbohydrate (sugar) with a by-product of oxygen released into the air.

You will also notice that even when comparing a plant mineral composition report from a ryegrass to an analysis from a clover plant there will be a significant difference between them. In other words there is a balance of nutrients needed from the soil (the other 5% of the plant), it is not just nitrogen, phosphate and potassium (N-P-K). Notice also that plants require trace elements in very small amounts – in parts per million. Although these are needed in tiny amounts does not mean that there is no point in supplying them. These trace elements are compo-nents of enzyme systems and are vital not only for the health of the plant but also for animals and humans that consume them too. NPK fertiliser, or rather the phosphate content of this conventional fertiliser, does not supply nearly enough of these trace elements – copper, cobalt, zinc, manganese and molybdenum supplied at rates in the parts per million of 5–50, 10–20, 200–400, 10–30 and 0.5–2.0 respectively from this type of fertiliser.

Water uptakePlants contain up to 90% water and are constantly losing water so a constant supply must be provided through root absorption from the soil. There is water loss through the leaves, which is called transpiration. On the underside of the leaf there are thousands of tiny pores (which are visible with a microscope) called stomata, which allow for the movement of water, gases and even uptake of other elements that might be present in the water. Plants can regulate the size of the stomata and can slow down losses of water in dry periods, but there is a balance here as this transpiration is used to cool the leaves in hot weather. One element that is considered vital to correct stomata func-tioning is potassium but this is seldom deficient. Water can be ‘lost’ in the plant exudates that leak out of the tips of the roots (see later section).

The upward flow of water is able to carry nutrients from the soil to the plant by way of vessels or vascular tissue called xylem. The other vascular tissue called phloem carries food (energy in the form of sugar) downwards to other parts of the plant and to the roots.

What factors affect root uptake of water?The water content of the soil is important. As mentioned before there is water in pore spaces, and some of this is plant available

and some is too tightly held by the soil particles to be used and so is unavailable to the plant. Salt content of the soil has an affect. Roots growing in soils high in salt or where high appli-cations of muriate of potash fertilisers have been used will find it harder to absorb water. Some crops can tolerate high salt soils and some soils are naturally high in salt but excessive use of salt fertiliser aggravates the condition.

Roots usually have thousands of tiny root hairs near their tips, which extend out into the soil. These are not seen by the naked eye and are broken off when a plant is pulled from the ground. These hairs increase the surface area of the root by up to 20 times and allow for more efficient absorption by having a greater access to the soil. This area of the roots should be considered the digestive system of the plant. A large healthy root system is vital for drought resistance for a crop and these roots do best in un-compacted soil. Those soils that are compacted with tight small pore spaces will hold little water and a plant on a hot day, with wind and low humidity, will lose water so fast that eventually it will wilt. It may recover over night when transpiration is slower.

Crop nutrientsPlants also need varying amounts of each element throughout the growing season and may not completely meet all the plants’ needs all of the time. The role of the organic farmer, therefore, is to assist plants as much as possible with a balanced nutri-tion regime, which as has already been made clear requires the farmer to work with the biological life in the soil.

Nutrient requirements are small at the beginning of a crop’s growth then increase dramatically during peak vegetative growth and then during seed production. For example, look at this soybean crop’s mineral uptake of the following 5 minerals in kg per hectare:

Nutrient 40 days

80 days

100 days

120 days

140 days

nitrogen 9 140 11 74 73phosphate 1 24 4 14 14potassium 7 119 8 46 44calcium 3 35 8 13 0magnesium 1 11 1 6 4

Adapted from Zimmer, Gary F. 2000. The biological farmer.

Under conventional fertilisation practices it is not uncommon to put most of the NPK and perhaps calcium in at the time of planting or having another application at an early stage during the growth of the crop (and hope that if there is a lot of rain it is not leached out), but as you can see from the above figures that nutrient requirement for each element changes throughout the whole period of crop growth. That is why under the organic system we need to manage the decay cycle and provide a balance of nutrients both soluble and slow release so that we can grow a healthy and good quality crop. Management of

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the decay cycle means that the residues are digested by mid-summer so their nutrients can become available for the next crop.

Soils do have huge amount of nutrient elements – more than a crop will need but a lot of it is unavailable due to being held by soil particles or in the complexes of humus or in the bodies of soil microorganisms like bacteria and fungi. Some of these nutrients can be made available through natural processes like weathering (temperature and precipitation), the release by the roots of mild acidic substances that can cleave off certain elements, the action of microorganisms in the soil excreting or vomiting substances into the soil, and there is the microbial decay of plant material or other litter which also releases nutrient elements.

In an organic system with a healthy soil food web the natural release of nutrient elements can often meet much of the plant’s element needs, but in some types of soil like sands with low cation exchange capacity (CEC – see later section) or if very high plant densities per hectare are planted then there will still be shortfalls in crop needs. Organic farmers will notice though with time that the amount of fertiliser inputs will reduce after several years as natural nutrient release will ‘kick in’. It is thought that about 5% of a typical soil’s total supply of nutrient elements can become available each year.

A crash course in chemistry!We now have to get into a bit of chemistry to uncover the next bit of the soil system and how this affects the soil. First, some terms that you will have to become familiar with. It is not the goal of these notes to turn you into soil chemistry experts but there are some basics that if grasped will enable you to better understand what it is that you are trying to achieve in the soil.

The 16 nutrient elements – oxygen, carbon, hydrogen, nitrogen, potassium, calcium, sulphur, phosphorus, magnesium, manga-nese, iron, zinc, chlorine, boron, copper and molybdenum – are often written down in the form of one of two letters (e.g. Ca, N, P, K.) Really this is just a code letter for each of these atoms. Plants have no knowledge of chemistry and don’t deal much with atoms as such but are more interested in ions. Ions are electrically charged atoms or molecules (more than one atom). These have a positive (+) charge or a negative charge (-). If an ion has a positive charge it is called a CATION like the calcium ion (Ca2+) and if it is a negative charge it is called an ANION like nitrate ion (NO3

-). Now if we remember the rule that opposite charges are attracted to each other you will be able to work out what happens if you put calcium ions into the soil in the form of lime. The soil particles have a large surface area and it is negatively charged so this will tend to attract ions like calcium.

What happens to the negatively charged ions or anions? These

are mainly found free in the soil solution but a small amount can be held on soil particles and some taken up by the soil food web. Excess anions can be lost from the soil in the form of leaching with excessive rain.

Nutrient ions held on soil particles are called exchangeable which means that they can be exchanged from the soil into the root. As soil scientists love to measure things they calculate a term called cation exchange capacity or CEC of a soil. You may picture this as holding sites in the soil, which are able to hold on to cations or the positively charged ions. As a general rule, if your soil has a high CEC value this means that it is potentially very fertile and/or is high in organic matter. Sand type soils have low CEC readings whereas clay, loam and peat soils have high CEC readings in a soil test report.

If cations like calcium, magnesium or potassium are removed from a holding site in the soil something always wants to balance this event so what happens is that a hydrogen cation (H+) slips into the spot. This is a sure way of making your soil acidic or making the pH of the soil low. pH is another chemistry term that you will have to come to grips with and it is another way of measuring the amount of hydrogen cations in the soil.

A lot of emphasis is put on the pH of a soil and most farmers know that if you want to make the soil less acidic (or increase the pH reading) then you have to add lime to your soil. Some soil consultants only recommend lime to ‘fix’ pH but the real reason we want to add lime is to replace the store of cations on to the soil particles or increase depleted nutrients. If you need to increase the pH of a soil there are in fact a choice of cations that can be applied – calcium, magnesium and potassium – and the choice will depend on what is needed to bring the cations back into balance (see later section).

Nutrient uptake by rootsThe way elements are taken up by the root was thought to involve some of the following mechanisms:

• There are ions dissolved in water that simply flow into the root along with the water the plant root was absorbing.

• There may be a slow seep along concentration gradients.

• There is active transport where a pump in a root cell can pump ions inside against the normal flow or diffusion.

• There is also a term called base exchange. Here is another bit of soil chemistry terminology you will have to be familiar with. Remember those cations we spoke of before, they are also known as bases - the ability to make the pH increase or go more alkaline. Base exchange can occur when the root releases hydrogen ions from its tip and this swaps places on the holding site of the soil with a base or cation like calcium or magnesium so the soil becomes more acidic and the plant gets a cation.

The above-mentioned systems may indeed work but there are also soil microorganisms functioning and the role of fungi in

element transport cannot be overlooked. The hyphae of the fungi are often distant from a root and can source minerals at a distance and transport them to the plant. It is thought that the plant drives the mineral uptake of the fungus. When the plant registers a need for a particular element it organises the fungi to source it and in return gives the fungus a carbohydrate

product (food) that the plant has manufactured during sunlight hours. The mycorrhizal fungi are thought to function in this manner. These fungi are in close association with the plant roots. You will see that this system is highly desirable for your plants as it means that its range for accessing distant ‘elements’ is greatly increased by using the fungal hyphae.

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Soil test reports and interpretationNow we will have a look in more depth at soil test reports. The goal here is not to make you an expert in this area as it is very complex but if we look at the common terms used on a soil test report and explain these you will get some idea as to what it is you are trying to achieve with the chemistry side of the soil test report.

Unfortunately, each soil testing laboratory has its own system of reporting the results so no two soil test report formats will look the same (and in fact it is seldom found that no two soil laboratories testing the same sample of soil will get the same results either!) so we will look at all the terms used and give you some ideas as to the goals you to attain with your soil for improved soil, plant and animal health.

One useful aspect of a soil test report is that it reports the level of cations in percentage terms. You should see a line like

K 3%

Ca 70%

Mg 12%

Na 0.5%

or it might be down the bottom of the report written as

K 3% Ca 70% Mg 12% Na 0.5%

If the report does not have this (plus a few other features like bulk density, pH etc.) then it may be more difficult for your consultant to help you with recommendations. Send your soil to a laboratory that does indicate cation ratios in a percentage form.

With organic farming there are too many benefits to be gained by altering your soil cation balance towards an ‘ideal’ ratio, so working towards a ‘balance’ does bring rewards. The rest of a soil test report really indicates whether or not you have most elements present to grow grass or a crop (quantity). However, under organic or biological systems this is not enough and we actually want quality as well.

How has the cation balance of potassium, calcium, magnesium and sodium been determined?

In actual fact it was the animal’s preference for grazing in past history that gave the best indication for the balance required for cations. Animals are incredibly good nutritional chemists if they are allowed to be. If there is a choice between poor food and good food, the animal will always be able to detect, without any laboratory readout reports, the difference and will devour the better food. Under current farming practices we often deny animals this choice.

If we look at the work of William A. Albrecht he found some interesting trends in soil test analysis when he compared the places animals like to graze and the health of these animals. (Albrecht’s literature has been collected in four volumes –known as the Albrecht Papers. He spent his lifetime working with soils and his papers began to be published in 1918 and continued until his death in 1974 – see references).

Albrecht has suggested that if we get the soil’s exchange

capacity saturated with around 70 to 75% of calcium,

around 10 to 15% magnesium, 2 to 5% potassium

and up to 1% sodium we will then have the growth of

forages rich in protein along with carbohydrates and also

carrying many of the other inorganic elements, vitamins

and enzymes as it was at these soil sites where animals

preferred to forage and had the best of health. Thus we

can alter the exchange capacity of the soil to grow more

nutritious food. (Albrecht, 1975 (Vol. 1), p 412.)

There is potentially a lot to be gained by moving your soil’s cation ratios to this range as finance allows. Soils widely out of cation balance, with a high CEC (cation exchange capacity) reading may be too expensive to correct quickly so the ‘repair’ may take up to 5 to 15 years, whereas sandy soils or ones with a low CEC value may be corrected quickly. You will of course realise that this is not the sole solution to soil, plant or animal problems as we are only considering the chemistry side of the soil here. There are still the biological and physical aspects of the soil to consider in relation to identified problems.

Some examples of soil test reportsAs mentioned previously each soil testing laboratory will have its own way of reporting its findings so no two laboratory reports look the same or report all the same elements. It is a good idea to gather trends with regular soil testing and stay with the same testing agency so that you can monitor the trends that are occurring in your soil on your farm.

There are two different soil reports shown here and presented as examples.

Please note that there are many soil laboratories in New Zealand. We are not advocating any particular laboratory in this Resource Guide.

An example of a soil test report – Hill Laboratory (New Zealand).

Client: Joe Bloggs

Address: Swamp Rd, Timbuktu.

Sample Name: Hill block – no fertiliser for years

Sample Type: Soil – to grow mixed pasture

Analysis Level found Medium Range

pH 5.4 5.8-6.3Resin P ug/g 19 40-75Olsen P ug/ml 11 20-30ASC/P Retention% 43 30-60Potassium me/100g 0.33 0.5-0.8Calcium me/100g 4.9 6.0-12.0Magnesium me/100g 1.44 1.00-3.00Sodium me/100g 0.12 0.2-0.5CEC me/100g 16.7 12.0-25.0Base saturation % 41 50-85Volume weight 0.71 0.6-1.0Sulphate S ug/g 4 7-15Org. sulphur ug/g 6 10-20Organic matter % 7.4 7-17

Base saturation data %K 2.0 %Ca 29 %Mg 8.6 %Na 0.7MAF Cation units K 5 Ca 4 Mg 23 Na 4

Another example of a soil test report – this one from Brookside Laboratories, Inc • U.S.A

Client: Joe Bloggs

Date: 8/12/1999

Sample location: Paddock 25 Lab No.: 0260-1

Total exchange capacity (ME/100g): 28.17

pH (SMP Buffer): 5.9 pH (H20 (1:1)): 6.2

Organic matter (humus) %: 70 (peat soil)

Anions soluble sulphur ppm 26Anions phosphorus easily extractable kg/ha P as P2O5 708Anions phosphorus easily extractable ppm of P 138Anions phosphorus Bray II kg/ha P as P2O5 641Anions phosphorus Bray II kg/ha ppm of P 125Anions phosphorus Olsen kg/ha P as P2O5 369Anions phosphorus Olsen kg/ha ppm of P 72Cations calcium kg/ha 8541Cations calcium ppm 3813Cations magnesium kg/ha 1214Cations magnesium ppm 542Cations potassium kg/ha 851Cations potassium ppm 380Cations sodium kg/ha 92Cations sodium ppm 41Cations aluminium (KCl Ext.) kg/ha 11Cations aluminium (KCl. Ext.)ppm 5

Base saturation percentCalcium % . . . . . . . . . . . . . . . . . . . . 67.68Magnesium % . . . . . . . . . . . . . . . . . . . . 16.03Potassium % . . . . . . . . . . . . . . . . . . . . 3.46Sodium % . . . . . . . . . . . . . . . . . . . . 1.63Aluminium % . . . . . . . . . . . . . . . . . . . . 0.20Hydrogen % . . . . . . . . . . . . . . . . . . . . 12

Extractable minorsBoron (ppm) . . . . . . . . . . . . . . . . . . . . 0.68Iron (ppm) . . . . . . . . . . . . . . . . . . . . 372Manganese (ppm) . . . . . . . . . . . . . . . . 16Copper (ppm) . . . . . . . . . . . . . . . . . . . . 2.41Zinc (ppm) . . . . . . . . . . . . . . . . . . . . 8.02Aluminium (ppm) . . . . . . . . . . . . . . . . 554NO3-N . . . . . . . . . . . . . . . . . . . . . . . . 12.5NH3-N . . . . . . . . . . . . . . . . . . . . . . . . 11.7Total acidity (ME/100) . . . . . . . . . . . . 12.6Molybdenum (ppm) . . . . . . . . . . . . . . . . 0.47

Metric conversions and Milli Equivalents can be found in Appendices 4 and 5

Volume Weight/Bulk Density information can be found in Appendix 5

Observing Clovers and legumes in Appendix 6 give soil deficiency indicators.

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Terms on a soil reportLet’s now look at the typical terms on a soil report in more depth.

Cation Exchange Capacity – CEC Cation exchange capacity (CEC) is a measure of the nega-

tively charged sites in a soil that have the ability to hold exchangeable cations and is measured in milli-equivalents/100grams (see section below).

Examples of cations are:

Calcium Ca2+

Magnesium Mg2+

Potassium K+

Sodium Na+

Hydrogen H+

Aluminum Al3+

There is no desired CEC value – it is dependent upon the type of soil, (e.g. peat, clay, loam etc.), but you can increase a soil’s CEC by adding organic matter to it. Organic matter holds nutrients and water. Therefore you can increase the fertility (CEC) of a soil this way.

The other way cation levels are expressed are in milli-equivalents per 100 grams (me/100g). This way of reporting cations will be seen on some soil test reports. Rather than confuse you with another system, see Appendix 4 if your soil test report is listed in milli-equivalents.

Total base saturation This is the measure of the fraction of the negative holding

sites (sometimes called the soil colloid) in the soil that are occupied by bases.

Exchangeable cations can be divided into two groups:

• Bases - these are cations which are alkaline and therefore raise the soil pH e.g. Ca2+, Mg2+, K+, Na+

• Acids - these are cations which increase soil acidity and therefore lower pH e.g. H+, Al3+ (Aluminium – one of the most common elements of the soil!)

Every CEC holding site must have a cation attached to it so the site is then electrically neutral - a negative charge plus a positive charge equals zero. The eventual pH of the soil will be affected by whichever cations predominate on these exchange sites.

Total base saturation is calculated by adding all the cations of calcium, magnesium, sodium and potassium together that were found in the soil, then expressing this as a percentage of the CEC value. For example, a base saturation of 75% means that 3 out of 4 holding sites on the soil have bases attached and the remaining 25% must have acid attached. Range required depends on the soil but from 50 to 85%.

Individual base saturation percentage levels - BS%

The individual base saturation levels are used in organic and biological farming to gauge the balance of cations on the

holding sites in the soil expressed as a percent.

The general cationic balance are (for a soil in the pH range 5.8 to 6.5):

Calcium 70 – 75%

Magnesium 10 – 12%

Potassium 2 – 5%

Sodium 1 – 2%

Note: attempting to achieve the ideal level may not be economic or practical. For market gardeners or specialty crops on varying soil types these individual BS% levels may differ. For example, for a peat soil with a very high CEC reading, it may be more economically viable to work towards a 50% BS for calcium. Huge quantities of lime would be involved otherwise. Some soils (sands) may have such a low CEC that there is not enough capacity to hold what the crop needs.

Organic matter (OM) This is a measure of plant and animal residues in the soil

– the un-decomposed residues. Organic matter is the main contributor to the soil’s CEC, and is also a source of many nutrients, especially nitrogen. It improves the physical structure of the soil, it increases water filtra-tion, improves tilth, decreases erosion and supplies plant elements or nutrients.

Organic matter is calculated from the organic carbon level.

Organic matter (%) = Organic carbon (%) x 1.72

Some laboratories offer a separate test for percent humus, which measures only the decomposed organic matter.

Humus (%)• The dark layer to the topsoil marks the humus layer

• Humus holds the reservoir of nitrogen, boron, sulphur, phosphorous and zinc

• Humus can be quickly destroyed by conventional farming practices (e.g. ploughing wet [sodden] soils is the fastest way to destroy humus)

• Humus can be built up by sound biological practices

• Humus content influences water holding capacity.

Some laboratories report the humus level. Once organic matter is completely decomposed by the microorganisms the remaining residue is humus. Humus holds the reservoir of nitrogen, boron, sulphur, phosphorous and zinc. Humus is far more successful in holding nutrients than clay, by a factor of three.

Again there is a humus percent value which is desirable – high humus soils are not always the best as they can have copper deficiencies (peat soils for example). Low humus soils (less than 2.5%) keep the microorganisms on a starvation diet let alone the plants (sand soils).

Humus can be built up in the soil by increasing the efficiency of microbial breakdown of plant residues.

Other notes on humus

Let’s look at the beneficial properties of soil humus.

• Humus releases plant nutrient elements slowly over the growing season cafeteria style. On conventional farms this process is sped up by the overuse of nitrogen.

• Humus improves the physical properties of the soil and helps to hold water and certainly adds to the tilth and friability of the soil

• Humus is a food source for microorganisms so where ever humus extends down to in the soil microbes can feed.

• Humus aids in making insoluble plant nutrients soluble through chelation reactions. This means that it can help breakdown fertilisers that are in the wrong form or tied up or complexed.

• Humus has a high exchange capacity for plant elements hence the reason for three times the holding capacity of clay. This holding bond is extremely strong as scientists have isolated humus then attempted to knock loose its held nitrogen by the use of strong acids but nothing worked, and yet the humble plant root can do this by the exudates from the roots. The micro-organisms also have enzymes that can achieve this, but man cannot!

• Humus increases the soils buffering capacity humus content influences water holding capacity – soils with low humus dry out very fast

• Humus is a dark colour and favours heat absorption so permits early growth of crops and pasture and early spring planting - it also allows soils to dry out quicker after a wet period for more timely field entry for cultivation

• There are certain components of humus that may exert plant growth-promoting effects

• Humus reduces toxicity of certain substances both man-made and natural. If soil has been depleted of organic matter and beneficial microorganisms, then to start the reversal. Organic matter or manure has to be put into the soil along with soil microorganisms via compost or compost tea (see later section)

• Ploughing wet (sodden) soils is the fastest way to destroy humus. Working wet soils annihilates air and water spaces – there is no environment favourable for the microorganisms.

• To make humus you need food + air + microorganisms. To make humus you need a carbon to nitrogen ratio of about 10:1. Crop residue like corn has a ratio of 60:1 so if there is not enough air for the microorganisms to work and multiply in they cannot get this ratio down to 10:1 so the quality and quantity of humus evaporates.

pH• This is a measure of the acidity or alkalinity of the soil

caused by hydrogen ions

• Soil pH between 6.2 and 6.8 is considered ‘ideal’ for most crops.

Most chemistry books have pH = -log[H+] but it is more prac-tical to just remember the scale below and where the soil pH should lie. The pH scale runs from 0 to 14.

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Most acidic 7 is neutral pH Most alkaline

Any pH below 7 is acidic and any pH over 7 is alkaline. Any pH that is a whole number above or below another has 10 times fewer or greater hydrogen ions. pH is important because of how it influences the chemical and physiological processes in the soil and the availability of plant nutrient. Soil pH between

6.2 and 6.8 is considered ‘ideal’ for most crops.

The hydrogen percent saturation is zero at a pH of 7. In an acid soil the hydrogen ion has replaced calcium, magnesium, potassium and sodium on the soil holding sites. pH becomes self adjusting when calcium, magnesium, potassium and sodium are in proper balance or equilibrium. Where a pH is low this means that there is a shortage of fertility elements, not necessarily only calcium. Magnesium, pound for pound, could raise the pH up to 1.67 times as high as calcium. A soil high in magnesium and low in calcium could test pH of 6.5 and still be entirely inadequate for the growth of lucerne. Any one of the four major cations can in excess push the pH up and any one of them in lower amounts can push the pH down. Once a balance of the major cations has been found at around pH of 6.3 for farm crops you will find plants will be prompted to flourish.

There are a couple of ways to measure pH. One is the water pH method – the other is a salt pH method.

For exchangeable hydrogen you always need the water pH. If the pH is above 7, exchangeable hydrogen will be zero. At a pH of 7 the soil is neutral and saturated with something else other than free hydrogen ions. At a pH of 6.9, exchangeable hydrogen is always 1.5% at pH 6.8 the exchangeable hydrogen is always 3%.

Every 0.1-drop in pH will increase the exchangeable hydrogen by 1.5%

Exchangeable Aluminium• Aluminium is not present in a plant available form in soils

that have a pH over 5.5 so this test can be requested for very acidic soils

• Aluminium toxicity can occur in soils where the pH is between 4.5 – 5.5

Guidelines

Level Exchangeable Aluminium (me/100g)

Low < 0.5Medium 0.5 – 1.0High 1.0 – 2.5Very high > 2.5

Source: Hill, Roger & Kay,Tony 1998. Field consultants guide to soil and plant analysis.

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Calcium – Ca• Calcium requirement or calcium excess in a soil can never

be determined solely by the pH reading of a soil test report.

• If it is economically possible Ca should occupy from between 70 to 75% of the negative holding sites in the soil in terms of exchange capacity for soil, plant and animal health.

• Liming products must be evaluated according to the calcium-magnesium content and according to the fineness of the grind

• A seven to one ratio (7:1) of calcium to magnesium in kg per hectare is desired if we are to achieve quality and quantity of crop or pasture grown

• Choices of calcium products include lime, dolomite, RPR (reactive phosphate rock) and gypsum.

Calcium is the foundation of all biological systems. It is the fundamental ‘growth’ inducing nutrient and the base against which other nutrients are reacted to release energy for crop and microbial growth.

This plant nutrient should occupy from between 70 to 75% of the negative holding sites in the soil in terms of exchange capacity (see section on Balance of Cations). If this desired exchange capacity can be attained there will be improved soil texture (the foundation of the soil), phosphorous and other micronutrients will become more available and the environ-ment for microorganisms will improve.

Calcium helps plants form better root systems, stems and leaves for efficient use of sunlight energy, water, carbon dioxide, nitrogen and mineral nutrients. Calcium is essential for building normal bones and teeth, important in blood coagu-lation and lactation. It enables heart, nerves and muscles to function and regulates permeability of tissue cells. It should be realised that calcium cannot be transported once it has been built into a leaf or root. It cannot be moved from the leaves to the seed or fruit. Newly formed roots, stems and leaves need an additional supply of calcium from the soil. This means that a continual supply of available calcium is required cafeteria style throughout the growing season for quality and peak yield. Calcium can, and often does, become a limiting factor in crop production. Over-use of nitrogen and or many other salt type fertilisers (see later section) or excess of magnesium or potas-sium leads to acidity or tie-up of calcium even in soils testing high in calcium. Measuring the amount of calcium in a soil at the start of the growing season does not mean that there will be enough available for the life of the plant.

Lime products need to be finely ground thus increasing the surface area of the particle so that the soil microorganisms can work the surface. Finely ground lime makes a greater surface area available so that any soluble calcium will be available directly to the plant root when water arrives. It may disappoint you to be told that carbonate limestone has approximately 2kg of soluble calcium per tonne and for gypsum this is closer to

25kg per tonne. Liming products must be evaluated according to the calcium-magnesium content and according to the fineness of the grind.

There is some controversy over the balance of calcium and magnesium. However most consultants involved with biological and organic farming systems agree with Albrecht’s work, that it is desirable to attain a balance of 7:1 calcium to magnesium in kg per hectare if we are to achieve quality and quantity of crop or pasture grown.

What are the other benefits attained when getting the 7:1 ratio of Ca: Mg?

• Positive effects on soil structure

• Improved humus content

• The growing of high quality pasture and crops

• Improved animal health with time

• A soil teeming with microorganisms and worms

• An improved soil nitrogen cycle.

It is not just the calcium to magnesium ratio that we are interested in but potassium and sodium as well. High soil potassium will decrease the plant’s uptake of sodium and if there are free nitrates or ammonium available in the soil, this often results in plants being low in both calcium and magne-sium. Pasture analyses done in New Zealand fit this profile all too often. Is it any wonder that farmers have trouble with grass tetany (staggers), downer cows and displaced abomasum, to mention but a few?

Can we have too much calcium in a soil? Yes! The day you get above 85% base saturation for calcium you will tie up 90% of the iron. Calcium can tie up magnesium, potassium, boron, zinc and copper due to the swings in the pH. Calcium does not tie up nitrogen though and crops grown on 80% BS% Ca will be very green but the plants will have a weak stalk due to the easy access of nitrogen into the plant. Copper will also be tied up and this nutrient is necessary for stalk strength. Any time there is a shortage of potassium, manganese or copper a weak stalk will be the observed result. High calcium influences potassium, high nitrogen influences copper, and high potassium influences the manganese content in the plant. Hence there is a reason to look for balance of the cations.

Sources

Lime, which is calcium carbonate (CaCO3) is the most common source of calcium. Not all limes are equal in calcium. They range from 28 to 38% calcium. Some of the ‘less pure’ lime rocks have a very interesting array of trace elements, which may be very useful. Pure CaCO3 is 40% Ca.

If the soil is deficient in Ca and Mg then use dolomite. Dolomite is another source of calcium but also has magnesium carbonate as well. Dolomite becomes available after 3 to 18 months. Another option is to use calcium and magnesium oxide (causmag) but the latter is restricted under the certifying agencies.

Gypsum is a mined calcium sulphate and has 23% calcium and 18 % sulphur and is another option.

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RPR is reactive phosphate rock and is about 33% calcium but also has phosphorous of 13%.

There are many other sources of calcium, but they are not permitted to be applied when certified under organic farming.

Magnesium – Mg• A very necessary element for soil, plant and animal health

• Often deficient in New Zealand soils

• Often found in excess in the soil relative to calcium and yet often low in pasture

• If in excess in the soil causes a hard, tight compacted soil.

Magnesium is part of the chlorophyll molecule in the plant cell. It is a very necessary element for plant health. Also involved with protein production, enzyme functions, energy release in cells, aids phosphorus uptake and starch transloca-tion. Magnesium causes instability of nitrogen in the soil and contributes to soil compaction if available in less than a 7:1 ratio with available calcium.

In medicine magnesium is an antacid and mild laxative and in the animal it is essential for nerve and muscle activity, and in bone structure and aids in growth promotion.

Some of the soils in New Zealand have a magnesium BS% above the ideal range – 10–12 % (e.g. moraine clay soils).

Sources

Dolomite (24%Ca, 12% Mg)

Organic Kieserite (15% Mg and 20% sulphur) – magne-sium sulphate mono hydrate

This is a soluble source of magnesium and is restricted.

Check with your certifying agency.

Magnesium oxide (55% Mg)

• Also known as causmag

• Check with your certifying agency as this is a restricted product

• Also reported to break down slowly in the soil.

Organic Patentkali (25% K, 17% S, 6% Mg)

• Not generally used on pastoral soils unless there is a severe shortage of potassium

Magnesium sulphate (Epsom salts)

• See above as for kieserite.

Bio-chelates

Guidelines

Base saturation of at least 10%. Work to a ratio of 7:1 ratio calcium to magnesium.

Reserve Magnesium On a soil test report reserve magnesium is used to estimate the long-term magnesium reserves in the soil and is predominately used in research investigations.

Potassium – K• Potassium determines the thickness of the stalk and

leaves, the size of the seed and the number of fruit set

• Potassium is a catalyst and a prime requirement in chloro-phyll construction

• Aim for a potassium base saturation percentage of 2–5%.

• Excessive soil potassium causes many animal health problems

Muriate of potash is another name for potassium chloride. It is the most common form of potassium for farmland and is the cheapest. This fertiliser may be on the restricted list – check before using.

Potassium is a catalyst and a prime requirement in chlorophyll construction. It is also a governor for taking free nutrients from the air – carbon, hydrogen and oxygen. Potassium is needed so plants can make starches, sugars, proteins, vitamins, enzymes and cellulose.

Potassium can also be fixed by clays and thus cause a reduction in the expandability and the cation exchange capacity of the clay (makes the clay tight). Potassium can leach in certain soils, especially sandy soils.

Muriate of potash may have been overused in some cases in New Zealand agriculture. This is changing now. There is more monitoring of pasture potassium levels. If pasture potassium levels are high be very wary of adding more potash. Excessive potassium in the soil is usually mirrored exactly in the plants that are forced to grow in this medium and the stock eating these incorrectly mineralised plants may suffer many health problems in the guise of udder infections, foot problems, milkfever and staggers. Excess potassium can result in potassium substitution for calcium thus weakening the plant. Grazing ruminants do not find plants with excessive potassium content palatable.

Soil test report of potassium

It is not uncommon on some soil test reports to write the potas-sium as water soluble K2O.

To convert K2O to the element K divide by 1.4.

Guidelines

Potassium base saturation percentage of 2–5%.

This is the range given but it would be preferable in animal production systems to aim for 2 to 2.5%.

Sources of potassium

Muriate of potash – potassium chloride (60%K, 40%Cl)

Warning – may be on the restricted list – check before using

Potassium sulphate (42% K, 18% S)

A source of potassium and sulphate

Both the K and S are in a very available form

Restricted for use on organic farms

Check with your certifying agency

Patentkali (27% K, 17% S, 6% Mg)

• A source of sulphur, magnesium and potassium

• Used more in horticulture

• Restricted for use on organic farms.

Sawdust

Wood ashes

• Are quite dehydrating

• Use carefully.

Straw

Check with your certifier which plant grown products you would have to source from organic systems.

Why do some certifying agencies restrict potash (potassium chloride) use?

Lets look at the contents of potas-sium chloride: Potassium chloride is a salt-based fertiliser (see reference notes/appendix). Potassium chloride is 60% K or potassium and 40% chloride.

The chloride content is an effective bug killer and kills microorganisms in the soil. Chloride can also harm crops with roots sensitive to chloride. Why would you add this type of product to the soil when it will kill off your soil friendly microbes and hurt plant roots when you could use the likes of potassium sulphate, of which the sulphate ion is more user-friendly, to both the roots and the soil microbes?

To kill all your bugs in your swimming pool chlorine is put in at a rate of 2 ppm. That is 2 parts of chlorine to 1,000,000 parts of water. This equates to 4.5kg of chloride per hectare. It is not uncommon for a fertiliser recommendation to supply 100 kg of potash per hectare100 x 40% is 40 kg of chloride. Now 4.5 kg of chloride can kill all the bugs in your soil and farmers are often putting more than 10 times this amount on our soil?

It is questionable as to whether potash should be used on agricultural soils due to its chloride content.

This test is used to estimate the long-term potassium supplying potential of the soil and appears to be unaffected by short-term treatments.

Guidelines

Level Reserve Potassium (me/100g)

Very low < 0.1Low 0.1 – 0.2Medium 0.2 – 0.35High 0.3 – 0.5Very high > 0.5

Source: Hill, Roger & Kay, Tony 1998. Field consultants guide to soil and plant analysis

Sodium - Na• Sodium in excess will make a soil hard and elements unavailable – this is not generally a problem in New Zealand

• Is required for plant and animal health

• High application rates of sodium chloride are not advised.

Sodium is not required in huge amounts in the soil but is very important for some particular plants and for animal health. When it is present in soil it is a very active cation. Sodium when present in a cell is a regulating element that governs osmotic pressure in cellular tissues and fluids. Lack of sodium is generally not a problem with plant growth in New Zealand because of our proximity to the coast and strong winds. Inland areas may well need an input of sodium however.

Manure and compost can add sodium and it is wise to monitor the base saturation percentage level and ensure that it does not go above 3%.

Guideline

Na+ at 1% base saturation in soil or at a ratio of 1 : 2 Na:K. If soil potassium BS% is very high then the sodium BS% will have to be increased.

Some farmers have noticed that there needs to be more fertiliser applied in an attempt to keep the same yield of produce. Initially with the addition of potash there will be a release of nutrient and non-nutrient cations as they are squeezed out of the soil, which is great if there is a crop growing which needs these cations, a microbe that wants to use them or water to leach them away, but this is thought to be at the expense of soil structure and at the expense of net long term capacity.

What happens to the chloride part of the potash? Chloride salts alter the behaviour of clay and it cluster in lumps making it more difficult to till. When potash is added to a clay soil which has high calcium content, where the potassium is fixed in the small pores the chloride is left free to attach to calcium and also Aluminium in the soil. We have the formation of two more types of salt that are even more effective in solidi-fying clays through aggregation (CaCl2 and Al(Cl)3). Sodium chloride is bad enough at doing this but calcium and aluminium chlo-rides are worse. Now we have reduced pore space, decreased water holding capacity and oxygen levels.

So in summary, with the over-use of potash and in conjunction with high nitrogen appli-cations to the soil, the following features could be expected:

• Soil hardening

• Poor fertility

• Declining response to equal amounts of fertiliser

• Soil compaction

• Erosion

• Reduced water holding capacity

• Limited nutrient reserves (tiny pores that cannot fit the large cations but fit potassium and ammonium ions).

Reserve Potassium

The amount of slowly released potassium is often more significant than the amount of immediately available potassium.

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Application rate

Sodium chloride should not be applied at rates greater than 10kg per hectare. See the section on potassium chloride with regards to the effect of chloride on soil inhabitant wellbeing.

Sources

Sodium chloride

Sodium chloride is restricted under the organic certifying agencies. There will have to be a demonstrated need if it is to be used.

Phosphorus – P• Phosphorus is the element, phosphorous and phosphate

are compounds made up from phosphorus and oxygen

• Phosphate is the major catalyst in all living systems. A deficiency of phosphate causes living systems to come to a grinding halt.

• Phosphate doesn’t move in the soil without help

• Is essential for photosynthesis

• A Resin P test should be requested when using RPR sources of phosphorus

• For 40 kg of phosphorus per hectare you will need around 300kg/ha of the RPR .

Phosphorus is an element whose release in soils depends on decomposition of organic compounds. Phosphorous is contained in all tissues with concentrations most pronounced in young plants, seeds and flowers. All phosphate sources (rock phosphate, superphosphate, triple-superphosphate and organic fraction phosphates, proteins and phospholipids, etc.) undergo chemical and physical change before they can be utilised, so phosphates while present in a soil, may not be available.

Phosphorous is the major catalyst in all living systems and is essential for building sound bones and teeth (in conjunction with calcium) and for the production of sugars, carbohydrates and fats and is necessary for enzyme activation – especially the phosphate energy cycle.

It is necessary for photosynthesis and metabolism to occur. It is a key to obtaining high crop refractometer readings (see later section on Brix).

Plants take up less phosphate than they do nitrogen, potas-sium and even sometimes magnesium and calcium and yet it is considered to be a major plant nutrient. If you look at plant analysis figures, the phosphorus content is usually between 0.2 and 0.4% so 100kg of plant material will only contain 200 to 400 grams of phosphorus.

Phosphorous can move within the plant and is ‘cycled’ via the energy system of ADP and ATP. It is beyond the scope of this Resource Guide to get into the details about this energy system but basically there are molecules that have the ability to gather and release phosphate ions and energy. Adenosine mono-phosphate can hold another phosphate and become adenosine di-phosphate ADP (this requires an energy input) and ADP can

become ATP or adenosine tri-phosphate (this requires an energy input as well) if it collects another phosphate ion. If ATP is converted to ADP then energy is released and a phosphate ion is available. Without this energy cycle of phosphate every-thing in a plant would come to a grinding halt. This energy system also functions in soil microorganisms, plants, animals and humans. It is a vital enzyme system so it is needed for the lifetime of the plant, microbe or animal.

Phosphate does not move in the soil. Where you put it is where it will stay unless wind erosion removes it, or water erodes the soil as in a flood, or soil microbes shift it. If you put phosphate on the surface of a soil and the soil dries out, the root hairs will not be able to utilise it nor the microbes as they will die or move if water disappears. Phosphorous availability is depen-dent upon moisture, aeration, the lack of compaction, microbe activity and the pH of the soil. When you have soil compaction the root hairs cannot grow and will not come into contact with phosphorous. If there is no air the microorganisms will not be able to function so there be limited conversion of phosphate into a plant available form. At a pH of around 6.5 you are going to have good availability of phosphate.

There is ongoing debate about the relative performance of rock phosphate versus acid phosphate with longer term research indicating that rock phosphate outperformed acid phosphate (superphosphate) in studies lasting more than three years. (Sinclair et al, 1990.) However, rather than getting involved in an argument over the relative merits of the two types of phos-phate let’s keep in mind that the key to phosphate availability is through a suitable pH and soil microorganism activity. For those that use the rock phosphate it is even more important that you have microorganism activity in your soil as you do not have the benefit of soluble phosphate like that available from superphosphate. If there is a choice between rock phosphate and soft rock phosphate get the soft rock phosphate.

Phosphorus is thought to be adsorbed into a plant as ortho-phosphate ions H2PO4

-, which has a single negative charge or HPO4

2- which has a double negative charge. The point here is that you will see that hydrogen is required if you are to get phosphorus into a plant so this means that there must be enough hydrogen present on hand for these compounds to be made, i.e. an acidic testing soil – under a pH of 7.

Laboratory reporting of phosphorus

A lot of soil test reports from overseas will report the phos-phorus (the element P) as phosphate just to confuse us all. If you need to convert phosphate, which is written as P2O5 to P then divide by 2.29. P = P2O5 / 2.29.

There are several tests for phosphorus depending upon whether the soil is analysed in New Zealand or offshore. In New Zealand it is common to see an Olsen P test or a Resin P test.

The Olsen P The guidelines for the Olsen P have been set at a range between

• 20 and 30 ug/ml for pasture/crop soils

• 35 for pumice and peat soils

• 12 for sedimentary soils.

The Resin P test is an alternative test and is one that is particularly recommended for soils where RPR (reactive phos-phate rock) or other slow release P fertilisers have been used. This test gives an idea of the reserves of phosphorous in the soil. Get into the habit of asking for the Resin P test.

The guidelines for the Resin P test is for a figure in the range:

• 50 - 100 ug/g for dairy soil and

• 40 to 75 ug/g for dry stock soil.

Phosphate does not move in the soil. If you need it down near the roots then you must work the phosphate down into the soil to get it there or rely on the soil microorganisms to get it there. If you have surface roots and the soil stays damp then phosphate on the surface will work.

Phosphate retention or ASC (Anion storage capacity)Phosphate retention refers to the phosphorous immobilisation property of the soil. This value is an inherent property of the soil and does not change (unless the soil is a peat soil that is mineralising). Although high phosphate retention soils may require 2 to 3 times the amount of phosphorus as capital or maintenance fertiliser than low phosphate retention soils, a retention of 80% does not mean that 80% of the applied P is rendered unavailable to plants.

Guidelines

Level Phosphate retention %Very low < 10Low 10 – 30Medium 30 – 60High 60 – 80Very high > 80

Source: Hill, Roger & Kay, Tony 1998. Field consultants guide to soil and plant analysis

Another two phosphorus tests are commonly done at labora-tories overseas:

P1 (weak bray extraction) – This indicates the phosphorous, which is readily available to the plant now. Guideline for P1, is a minimum of 25 ppm for soils with 3% organic matter, and 50 ppm is ideal.

P2 (strong Bray extraction) – This gives the amount of phos-phorous available now plus that, which should become available later in the season (active reserve phosphorous). Guideline for P2 is a minimum of 50 ppm while 100 ppm adds more crop/pasture quality and health. The ratio of P1:P2 should be 1:2.

Sources of phosphate

RPR – reactive phosphate rock - 13% P (33%Ca). (See types of RPR below.)

Bio-phos/ ComPhos – 13% P (36% Ca and 1% S – composted RPR

Chicken manure – 1.5% P

Liquid fish – 2% P2O5

Mycorrhizae fungi – varies with bio-activity (not available in NZ).

Oats cover crop – varies with nutrition of the oat crop.

Which RPR should I use?

Ideally you would want an RPR that tests high in phosphorus, has low levels of toxic elements (e.g. fluoride, and has a citric solubility of 30% or greater).

Gafsa RPR (Tunisia)

Gafsa is the worlds most recognised and widely used RPR.

Kosseir RPR (Egypt).

Sechura RPR (Peru)

Agent importing this is Asura Ltd.

Rates

For 40 kg of phosphorus per hectare you will need around 300kg/ha of the RPR.

How much phosphate is enough?

Maintenance recommendations: As a rough guide it takes 5 to 5.5 kg of P/ha per 100 kg/ha milksolids to maintain produc-tion on ash and 4.5 to 5 kg/ha per 100 kg/ha milksolids on sedimentary soils.

Why isn’t triple superphosphate allowed in organic systems?

An experiment was done where triple superphosphate was treated with a radioactive substance so that when the plant tissue was analysed it could be determined from where the phosphate came from – the fertiliser or from the soil. In the year tested it was a good growing season and it was found that the radioactive phosphate was taken up for only 8 weeks and that only 20% of the phosphate came from the fertiliser – the rest came from the soil! In poor growing seasons the phosphate was taken up for only 4 weeks and only 10% came from the fertiliser and 90% came from the soil. Triple superphosphate is therefore not a suitable fertiliser for organic systems – it has useful soluble phosphorous for only up to 8 weeks maximum under ideal growing conditions and then after this the phosphorous is bound up in the soil.

There is also potential for the soluble phosphorous and sulphur portion to be leached by rain and lost from the system if it is not utilised immediately. It has been proven beyond doubt by Massey University that the sulphate-S from superphosphate increases the losses of the critical nutrients calcium, magnesium, sodium, potassium and even nitrogen. This was published in the NZ Journal of Agricultural Research 1991, vol. 34.

The leaching of phosphate into waterway is a significant concern, as it only requires 0.1kg P/ha to cause eutrophication problems such as excessive weed growth and algal blooms. Typically from 1 to 3kg P/ha annually is lost to waterways.

Research by NIWA scientists have revealed that most P run-off from agricultural land occurs in run-off events (usually as a result of rain) in the first few days after application of the fertiliser. Where RPR was used instead of superphosphate, there was virtually no P run-off due to two main reasons: RPR is not water soluble as it relies on microbe activity in the soil and the acidity of the soil to release the phosphate slowly over time,

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and secondly that RPR is heavier compared to superphosphate so particles are less inclined to move unlike the light granules of super that can be floated off the surface in run-off.

What happens with superphosphate?

Superphosphate granules have an extremely low pH, as low as 1.5, which means that when you put it in a soil with a high pH like 5.8 or 6 it actually dissolves iron and aluminium which are present in the soil, which then re-precipitate with some of the phosphate from the granules and form relatively insoluble iron and aluminium phosphate compounds. This can in fact happen in any soils but is more significant in soils with high iron and aluminium such as ash soils. This part of ‘fixation’ cannot happen with RPR as these products are alkaline so the dissolu-tion of soil iron and aluminium does not occur.

Hence there are many reasons why certifying agencies allow the use of RPR products and bar the use of soluble type fertilisers.

Sulphur – S• Sulphur is vital for an enzyme to metabolise nitrates so

a deficiency can lead to nitrate toxicity in plants and the potential for animal health problems

• Even though sulphur is a secondary element like phos-phate it is needed by crops in often the same amount as phosphate

• Sulphate ions readily leach from the soil (unlike phosphate ions which don’t move).

More sulphur than phosphorous is needed to grow some crops and sulphur is essential for complete formation of proteins. Amino acids are assembled together to build a protein (a fundamental part of the muscles, enzyme systems and immune system immunoglobulins of plants, animals and humans) and there are 28 different amino acids. Three of these amino acids contain sulphur so if sulphur is insufficient or unavailable in your soil you will not have the manufacture of complete proteins in crops and pasture nor will they be available for animals and people.

Some other interesting aspects of sulphur• Sulphur is slow to be used in the soil as it has to be used by the microorganisms in the soil before becoming plant available. The finer sulphur is ground the better and ideally for crops it should be worked into the upper soil.

• Sulphur is insoluble in water

• Sulphur is acidic and will acidify the soil

• Sulphur is needed for the amino acids cysteine, cystine and methionine so is vital if complete proteins or enzymes or immu-noglobulins are to be made

• Sulphur is part of the B vitamins thiamine and biotin and coenzyme A (calves with thiamine deficiency will go suddenly blind, and if not treated progress to a staggering gait and then have fits and die)

• In high magnesium BS% soils sulphate ions can take excess magnesium with it

• In waterlogged soils sulphate and organic sulphur can be converted to toxic sulphides by bacteria and escape into the air so there is an important lesson here about avoiding waterlogged soils.

In New Zealand you might see sulphate sulphur (sulphate -S) or Extractable Organic Sulphur (Org-Sulphur) on a soil test report.

Sulphate sulphur

This test measures the readily available sulphur in the form of dissolved plus absorbed sulphate. Sulphate is an anion like the phosphate anion and retention of sulphate sulphur by the soil is related to the phosphate retention, with high leaching losses of sulphate being associated with low phosphate retention soils. This should be taken into account when considering sulphur fertiliser options.

Sulphate sulphur can be 2 to 3 times higher in soil in autumn due to moisture and temperature effects. This should be taken into account along with how the pasture or crop looks when using these guidelines.

Guidelines

Level Sulphate sulphur ug/g (ppm)

Very low < 4Low 4 – 10Medium 10 – 20High 20 – 50Very high > 50

Source: Hill, Roger & Kay, Tony 1998. Field consultants guide to soil and plant analysis

Extractable organic sulphur

Most of the sulphur in the soil is in organic forms (95%). This test is a measure of the readily soluble fraction of the organic S pool. The pool of sulphur is in a slow equilibrium with the plant available, inorganic form of sulphur. Being a natural source of S it is useful to have a way of assessing this compo-nent, especially if the sulphate sulphur test indicates low levels of the readily plant available form.

Guidelines

Level Extractable Organic Sulphur ug/g (PPM)

Very low < 5Low 5 – 11Medium 12 – 20High > 20

Source: Hill, Roger & Kay, Tony 1998. Field consultants guide to soil and plant analysis

Rates

Up to 30 to 40 kg/ha may be required depending upon the soil test report.

Sources of sulphur

Elemental sulphur – Under the organic system you are not permitted to use soluble sulphur so there is only the choice of elemental sulphur which is 99–100% S.

Gypsum – If there is a requirement for calcium and sulphur for the soil then application may be made to your certifying

agency as gypsum ,(Calcium sulphate) is restricted.

Animal manures – Animal manures contain sulphur but at low levels (0.1 to 0.2%). This would also add organic matter plus many other elements.

Carbon – C• Carbon is the element that conveys life to the biological

system

• Carbon controls the water content of soils

• Carbon buffers the soil, improves the tilth, and improves nutrient holding capacity.

Carbon is the element that conveys life to the biological system. It is the energy storehouse for the living system – all living systems must have carbon.

Carbon controls the water content of soils. Each kilogram of biologically active carbon can hold 4 parts of water. Every effort must go into retaining carbon in the soil system.

Biologically active carbon or the humus content of the soil ultimately determines that sustainability, efficiency and the productivity of the soil system. Carbon buffers the soil, improves the tilth, and improves nutrient holding capacity.

The greater the amount of carbon, the greater the energy reserve in that system.

Sources

Compost

Is perhaps the best source of carbon but not all compost is

equal (see later section).

Carbohydrates

Sugar, molasses, starch

Check with your certifying agency before use.

Crop residue

This must be incorporated in the first few inches of the soil and be broken down by microorganisms and with oxygen – must be aerobic.

Manures

Can be green manures – as above for crop residue

Can be animal manures – as above for crop residues.

Humates and humic acids

Must use judiciously – a little is great – a lot can be disaster

A very finite resource – best to build the soils own humates

Useful for chelating elements

Have a high CEC.

Hard coals

Not a humate – has been formed under huge pressure

Check with your certifying agency first.

Cannot be invaded by microorganisms.

A paradox with carbon

It is possible when developing an organic or biologically active

system to reduce the fertility of that system! If the carbon content of the soil is increased and humus levels increases too there will be an increase in the cation exchange capacity for that soil so there will be more binding sites on the soil to hold cations. With the increased carbon there will be a four-fold increase in the water holding capacity of the soil, which will dilute the minerals in the soil so it is possible to have reduced yields unless this is compensated for!

Carbon : Nitrogen Ratio

This ratio of organic carbon and total nitrogen gives important information as to the nature of the organic matter present in the soil.

organic carbon (%) = Organic matter (%) 1.72So now the C:N ratio can be calculated

Carbon : Nitrogen ratio = Organic carbon (%) Total Nitrogen (%)

Nitrogen - N• A major element

• Vital for the production of proteins (body tissue etc.)

• A versatile element in nature that can exist in many forms

• Some nitrogen forms can be lost by leaching

• Nitrogen has crucial significance in the nitrogen cycle in the soil.

Nitrogen gas is a colourless, odourless and tasteless gas. This element makes up 78% of the atmosphere, which would make one wonder how it could ever be in short supply for farming systems anywhere in the world. This element is vital for the nitrogen cycle by which nitrogen passes through successive stations in air, soil and organisms to achieve fixation. Nitrogen is a governing factor in the decay of woody materials.

This element is vital for the production of proteins, the main constituent of animals other than the skeleton. The percentage of protein is often calculated (rightly or wrongly) by multiplying the nitrogen content in an analysis by 6.25 or 6.4. However, nitrogen presence does not guarantee protein presence or protein manufacture, as protein formation requires both nitrogen and carbohydrate added to it.

There are many forms of nitrogen in a biological system. There are:

nitrogen gas in the air . . . . N2

ammonia . . . . . . . . . . . . NH3

ammonium . . . . . . . . . . . . NH4+

nitrite . . . . . . . . . . . . . . . . NO2-

nitrate . . . . . . . . . . . . . . . . NO3-

amino acids . . . . . . . . . . . . NH2 ( this group is attached to all amino acids)

proteins . . . . . . . . . . . . made up from many individual

amino acids.

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This versatile element is able to alternate between the nitrate form and the ammonium form via various processes in the soil and even the air. The nitrate nitrogen primarily promotes growth responses in the plant whereas the ammoniacal form promotes fruiting or a seeding response. Nitrate nitrogen must be altered before it can become a part of true functional proteins so consequently it is not the most efficient means of transporting nitrogen into the plant.

The plant, on the other hand, takes up ammoniacal nitrogen, in direct proportion to the density of the desirable rhizosphere microorganisms.

Nitrate is also a negatively charged anion so it will not bind to the soil colloid and can be lost with leaching. The ammonium cation, which is positively charged, is able to be held on the soil colloid.

What is the nitrogen cycle?

It is a cycle where nitrogen is constantly changing from one form to another and moving from the air to the soil, plants and animals.

There is the fixation of nitrogen by lightning in the atmosphere and also by the microorganisms in the soil with the formation of nitrate and ammonia.

N2 (gas) LIGHTNING NO3- (nitrate)N2 (gas) BACTERIA IN LEGUMES NH4

+ (ammonium)

There is then temporary immobilisation of nitrogen in proteins and other organic molecules

Mineralisation of organic matter releases nitrogen back into ammonia and nitrate.

There are also soil bacteria that can change ammonia into ammonium which is called ammonification, ammonium into nitrite and then nitrite into nitrate which is called nitrification.

Finally, yet other bacteria can convert nitrate into gaseous nitrogen or nitrous oxide called denitrification, which results in the loss of nitrogen into the air. These processes occur in anaerobic conditions. Other losses of nitrogen can come from leaching, soil erosion, escape of ammonia gas and the removal of nitrogen by harvesting crops or by the grazing by animals.

The nitrogen cycle on biological farms

This is the cheapest and most efficient way of harnessing nitrogen on your farm.

Do you remember what one teaspoon of healthy soil had in it?

• 100-800 million bacteria!

• several yards of fungi threads

• several thousand protozoa

• 10 to 20 nematodes.

How does the nitrogen cycle work when we consider the system happening within the soil?

If we analyse the Carbon: Nitrogen ratio from bacteria we find it is 5 C: 1 N

If we analyse the C: N ratio from protozoa we find it is 30 C: 1 NFor a protozoa to obtain its 30 parts of C how many bacteria must it eat? 6

How many units of N has it eaten? 6

How many units of N did it need? 1

What happens to the five in surplus? These get vomited back into the soil! A nitrogen source!

Now lets take a look at a nematode.When you break this down it has a C: N ratio of 200: 1How many bacteria must he eat to get enough C? 40

How many units of N have been taken in? 40

How many units of N did it need? 139 units of N get excreted back into the soil.

So in summary, many microorganisms work together to break down organic matter into a form that plants can use. The above mathematics example has probably over-simplified the complex nitrogen cycle, however, maintaining soil conditions that satisfy the microorganisms’ requirements should be the aim of all farmers – not just the organic ones. Don’t forget that the soil bugs need the same things as humans need to survive: warmth, oxygen, moisture, a source of food and a healthy environment.

It is imperative that this natural nitrogen cycle be nurtured by your farming methods so that nitrogen efficiency is enhanced.

Soil test reporting of nitrogen

The following may be seen on reports: available nitrogen and total nitrogen. They tend to be used in cropping situations.

Available nitrogen

This test gives and indication of the quantities of nitrogen that could be readily mineralised from the soil organic matter under ideal soil conditions.

Total Nitrogen

This test estimates the total nitrogen content of the soil and excludes nitrate-nitrogen. It does include nitrogen that is not available to the plant. The major use of this test is to provide nitrogen levels for the carbon/nitrogen ratio.

Guidelines

Level Total Nitrogen (%)

Very low < 0.1Low 0.1 – 0.2Medium 0.2 – 0.5High 0.5 – 1.0Very high > 1.0

Source: Hill, Roger & Kay, Tony 1998. Field consultants guide to soil and plant analysis

Sources of nitrogen

Under a certified system there is no ability to use synthetic nitrogen. The goal is to get the soil food web working efficiently so that the natural nitrogen cycle supplies the nitrogen. There will be times of the year where nitrogen

will be lacking and this is most likely when certain microbes are absent (even critical elements may be not be available) or when temperature and moisture availability are limiting the system (e.g. when the soil is either very dry as in a drought or the soil is very cold and the bacteria have become dormant).

Nitrogen can come from animal manure, compost and fish. Animal manure should ideally be composted before application. Compost must be of excellent quality and be suitable for the crop or pasture you are trying to grow (see section on Compost). Fish is a good source but is best if it is digested to some degree or composted. Please check that the fish product is certified for use if you are certified organic.

Blood is no longer an option due to the BSE outbreak in cattle in the Northern Hemisphere. Ruminant products like blood and bone must not be applied to agricultural land.

Green manures provide anywhere from 0.5 to 5% nitrogen. What are ‘green manures’? These are ‘crops’ that are grown up to the stage of going to seed and then mulched/roto-tilled or mixed into the soil aerobic zone – the first 50 to 70mm or so. These plants then feed the soil food web so that the next crop that is planted has access to these minerals etc. Legumes such as lucerne, sweet clover, red clover, beans etc. provide the most nitrogen. Grasses such as rye are also good in the growing phase and should be ploughed in before

seeding. Green manures are also good for factors other than the provision of nitrogen: they also build soil structure, hold moisture and feed the soil microorganisms. Biological farmers always strive to keep the soil growing some-thing so that the soil microbes always have a food source – the land is not left bare.

Trees can supply nitrogen. Nitrogen fixers like Tagasaste (tree lucerne) are another option.

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Trace elements or micronutrientsTrace element absence can mean plant health problems and animal health problems due to eating pasture/crops which themselves have deficiencies. Trace elements can be bulk spread but it is vital to balance the major cations first – calcium, magnesium, potassium and sodium. As the major elements (especially calcium) adjust towards the ideal ‘balance’ the whole soil will change and then the microorganisms will be more active and with more organic matter more nutrients will be released.

Trace elements commonly looked at by consultants in New Zealand are selenium, copper, cobalt, boron, molybdenum and zinc. Manganese, silicon and iron are also another three trace elements which need to be occasionally looked at but in the case of iron it can be in an excess state rather than a deficiency and can cause animal health problems.

Boron• Boron is commonly found to be deficient in clover in New

Zealand

• This element is involved with a huge number of processes in a plant

• Boron leaches easily from the soil

• Boron is toxic to grazing animals and to plants when given in excess

• Pastures deficient in calcium are generally low in boron too.

Boron is another very important trace element which is often overlooked. This element is involved with regulating flowering, fruiting, pollen production, seed production, cell division, salt absorption, carbohydrate metabolism, cell wall produc-tion, water use and nitrogen assimilation in plants. Boron is important for the filling of hollow stems of plants. Boron is also important for increased calcium uptake. It also functions in the synthesis of glycogen and the maintenance of body fat in animal life. Boron deficiency has also been linked with vitamin B1 (thiamine) deficiency in animals (blindness). It is also needed for bone construction in animals. In clover plants a red discolouration of the leaf is considered to be an indicator for boron deficiency.

Boron leaches very easily from the soil so should be checked for in soils or pasture analysis.

Boron is toxic to grazing animals. With solid application ensure rain washes the fertiliser off the pasture before grazing. Too much boron is also toxic to plants (especially maize), more so when temperatures are cool and the soil is damp.

Confusion often arises over boron rates. Borate and boron are often used interchangeably. Borate is oxygenated. Boron

is the element with no oxygen attached. Fifteen kg of 44% Borate 44G means about 2kg of boron. Borax is a naturally mined product and is the product allowed for use on organic farms.

Guideline

Boron – B – 2 ppm

(Called the Extractable Boron test by some laboratories in New

Zealand)

Rate

2kg /ha on an elemental basis (see above).

Chelates at a rate of 1 to 3 litres per ha.

Source

Borax (11% B)

Boron chelates

Moana Boron (4.5%) from Sieber

Chicken manure or compost – preferred

Check with your certifying agency first before use.

Cobalt• Cobalt is an element crucial for nitrogen fixation, especially

in legumes’ root nodules

• It is also important for the formation of bark, cellulose and seed-coat formation

• Cobalt levels in pasture are commonly found to be too low

• Deficiencies in farm animals expressed as ‘bush sickness’ or in mild cases as a lack of appetite.

Cobalt is the element in vitamin B12, which is produced by actinobacteria in the soil and gives the soil an earthy smell. Cobalt levels in pasture are commonly found to be too low. New Zealand’s native bush has many species, which have very high concentration of cobalt and other trace elements. Soils in New Zealand are generally not tested for cobalt. Herbage is more regularly tested. One of New Zealand’s native bushes called Rangiora (which is a large leaf bush – also called bush man’s friend) has a very high content of cobalt, as do gorse seedlings!

Source and rate

Cobalt sulphate (21% Co)

Rate: 350 g per hectare annually for 5–10 years then up to 100g/ha per annum.

Cobalt chelate (3.75%)

Sieber has Moana cobalt chelate which can be applied at 150 to 500mls/ha.

Copper• Often deficient in soils, plants and animals

• Animal deficiencies are expressed as ill-thrift

• Copper is the key to elasticity in the plant

• Copper is involved with many enzyme systems and root metabolism.

It is involved with many enzyme systems in helping to form amino acids and proteins and is a vital element for many microbes in the soil. Copper is vitally important to root metabo-lism. Copper helps produce dry matter via growth stimulation, prevents the development of chlorosis, rosetting and die-back, and in animals is essential for catalytic conversion of iron into red blood cells and it assists in tissue respiration. Copper deficiencies are becoming more of a problem in many types of farmed animals in New Zealand. There are several reasons for this but one of the major causes is the use of high doses of zinc used to protect stock against facial eczema damage.

One of the other reasons for low copper levels in animals is that the pasture often has very low levels of copper in it especially if it is predominantly rye or fescue. A sward with a greater variety of plant and herb species present will test higher for copper content then a rye/clover or fescue/clover pasture. High levels of iron in pasture test results are often due to soil contamina-tion, and cows at certain times of the year eat a lot of soil when grazing sodden pastures so this iron source can tie up copper. Sulphur and molybdenum levels, if high in pasture, also impact negatively on copper levels in pasture. So, in summary there are a lot of reasons for lack of copper stores in our grazing cows.

Guideline for copper

Copper levels in overseas soil tests are wanted to be at the 2 ppm level.

Source and rate

Copper sulphate (25% Cu) - for soil applications.

The use of copper sulphate should not preferably

exceed 4kg/ha as a single application (it is fungicidal).

Copper chelate – chelate foliar sprays are available in New Zealand.

Sieber has Moana Copper 6% which can be used at a rate of

500mls to 1.5 litres per ha.

Check with your certifying agency first before use.

Iron (Fe)• Is needed for chlorophyll production, energy release in

cells and in conjunction with cobalt is needed by nitrogen-fixing bacteria.

• Iron draws energy to the leaf by absorbing heat from

the sun; it makes the leaf darker, thus absorbing more energy.

• Often seen in excess in soils and even in bore water levels can be very high.

Iron will increase the waxy sheen on a crop.

Iron will increase the thickness of a leaf, which will geometri-cally increase the nutrient flow resulting in a greater production increase.

Generally not tested in soils by laboratories in New Zealand as this element is not deficient.

Guideline

Iron (Fe) - 20 ppm.

Source

Iron sulphate

Iron chelate – Sieber’s Moana iron (6.4%).

Black strap Molasses – a very good source where accept-able. Ensure it does not contain preservatives.

There are three major types of molasses:

1. Unsulphured molasses is the finest quality grade because only a small amount of sugar has been removed. It is made from the juice of sun-ripened cane and the juice is clarified and concentrated.

2. Sulphured molasses are made from green sugar cane that has not matured long enough and treated with sulphur fumes during the sugar extracting process. The second boil molasses takes on a darker colour, is less sweet and has a more pronounced flavour.

3. Blackstrap molasses are from the third boil. Blackstrap molasses have the lowest sugar content and the highest mineral content of all commercially available molasses.

Check with your certifying agency first before use.

Manganese (Mn) Not to be confused with magnesium (Mg)

• This trace element is required for normal growth and photosynthesis, oil production, energy release in cells and enzyme functions

• A seed not containing manganese is unable to germinate.

It is generally considered that New Zealand soils have sufficient manganese. Low pH soils could have manganese available at undesirable levels.

Guideline

Manganese – Mn – 20 PPM

Source

Manganese sulphate (28% Mn)

Manganese chelate (7.5% Mn)

Sieber has Moana manganese

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Royal jelly – expensive

Check with your certifying agency first before use.

Molybdenum - Mo• An important element in nitrogen enzyme systems

• Often present in excess in plant tissue causing copper defi-ciency indirectly

• Is not tested in the soil by laboratories in New Zealand.

Another important element for several enzyme systems, particularly nitrogenase and nitrate reductase, i.e. the enzymes to break down or build nitrogenous compounds. Plants grown on nitrate nitrogen have an increased need for molybdenum because of the increased need for the enzyme nitrate reductase. Molybdenum is a catalyst for iron in the bark or plant skin and is important in the integrity of the bark or plant skin. It gives the transparent look to the sheen on bark. It is most commonly used in legumes.

A deficiency of molybdenum can cause nitrogen deficiency in legumes. As soil pH increases, Mo availability increases.

Source

Molybdenum glucoheptonate

Molybdenum chelate – Sieber has Moana molybdbenum (6%).

Selenium• Commonly deficient in plants, animals and humans

throughout New Zealand

• No soil laboratory routinely tests for selenium in soils

• Selenium may be deficient in the soil or it could be that our pastures are not successfully harvesting it

• Monitor selenium levels annually in your livestock

• Selenium supplementation is usually in the form of foliar sprays to pasture or prills (solid fertiliser) to the soil (check with your certifying agency)

• Selenium is vital to the immune system

• Deficiencies can be recognised by white muscle disease in lambs (lame) and infertility problems in cattle (retained membranes).

Selenium is deficient in a lot of pasture and forage crops grown in New Zealand. There is some debate as to whether this trace element is actually deficient in the soil or whether it is a case of the required biology in the soil being absent or functioning at a reduced level so that the end result is a deficiency in the plant which transfers to animal and human deficiency.

The rushes that grow in wet areas on the farms accumulate selenium, which would tend to suggest that the element is in fact present in the soil or at least has been washed there. The Mahoe tree (Whitey wood) is one devoured by goats, sheep deer and cattle alike and is also high in selenium. The farming industry generally is aware of selenium deficiency and animals are boosted by a variety of ways but best option is to get it into the soil so that plants get it too.

Selenium is vital for enzyme systems and with Vitamin E is an anti-oxidant. It is important for the immune system too (see the Mastitis section).

Currently in New Zealand no laboratories test for the selenium content of the soil. A deficiency is usually detected on blood or liver testing from animals and then amendments are made to the soil.

Monitor selenium levels in animals regularly after application of selenium fertiliser to the soil (and keep your vet informed as well) before adding more to the soil.

Source and rate

Ag Sel prills 1% Se 1kg/ha per annum

Selcote Ultra prills 1% Se 0.5kg/ha per annum

These are restricted under a certified organic system so get appli-cation to use them.

Foliar sprays can be used.

Sieber (092390210) has Moana selenium 5% which can be used at a rate of 50 to 150mls/ha.

Silicon • Not tested for in New Zealand

• A minor element needed by some special types of crops

Silicon is not generally recognised as a plant nutrient but it is vital to some plants such as watermelons. The soil has quite large quantities of silicon. It is difficult to find a laboratory that can do an analysis for silicon. Silicon often turns up as a missing link in certain finely tuned fertiliser programmemes and seems to have some correlation to the carbon – calcium interac-tion in the plant and is generally used as a foliar additive. Silica is involved with protecting plants against mould penetration. The herb horsetail is also known as spring horsetail or scouring rush. It is a perennial and grows in all temperate zones of the world. This non-flowering, non-seeding plant thrives on clay-like sandy soils and likes marshlands and streams; some plants have adapted to growing along roadsides and on stony ground. Refined foods don’t have silicon so you will find abundant silicon in the shell of brown rice, bell peppers and leafy greens.

Source

The best source is the herbal extract of the horsetail plant (Equisetum arvense) at a rate of 5 grams per hectare.

Zinc• Zinc is an essential component of many enzyme systems.

It is also involved in making acetic acid in the root to prevent rotting.

• It allows dead twigs on trees to shed off.

• Excessively high phosphorous levels can depress zinc levels.

• Zinc is a trace element that is needed by animals for skin and hoof integrity.

• Excessive zinc in soil promotes weed growth!

Guideline for the soil

Zinc (Zn) – 5 ppm.

Source

Zinc sulphate (36% Zn).

Zinc chelate (7 to 10 % Zn) used as a foliar spray.

Sieber has Moana zinc.

Check with your certifying agency first before use.

Putting the theory into practiceThis is the part you’ve been waiting for – how to actually use all of the informa-tion we’ve given you so far and put it into practice on your farm. Before the advent of certifying agencies like Bio-Gro, Demeter and AgriQuality, farmers started to farm a little differently, picking up ideas and trying them on a small scale, even just on part of the farm, and when results were seen then there was courage to do more changes. If we look at the process these people took we find a common pattern.

These farmers were not happy with some aspect of their farming ways. Perhaps they were doing a process every year and not seeing the desired response. Most had identified animal health problems that were becoming more prevalent and seemingly more difficult to cure or eliminate. What is more interesting to note is that all these indi-viduals had decided in their own way that it was the way the soil was being treated that held the key to removing or reducing these problems and so what followed was a

change in the way that these farmers farmed ‘their soil’. Their next step was to remove some of these practices they perceived as being ‘damaging to the soil’.

We will list them down as ‘steps’ but they are really just the sequence of events in common with all these farmers who have changed away from current farming practices. The seven steps that have been identified from these experienced organic farmers are:

Step 1: Test and balance the key elements of your soil

Step 2: Choose fertilisers that are ‘soil friendly’

Step 3: Eliminate pesticide and herbicide use

Step 4: Increase the variety of plant species in the pasture

and planting trees on the farm

Step 5: Nourish the soil microorganisms.

If cropping then:

Step 6: Change from continuous cropping to a short

rotation of crop

Step 7: Control of the decay of organic matter by the

use of tillage to influence the soil to air to water

ratio in the soil.

Step 1: Test and balance the key elements of your soil

In the early stages there is often an appreciation by the farmer that the current nitrogen, potassium and phosphate fertilisa-

tion practices are not resulting in better animal health, plant health or a stronger bottom line in the accounts. The starting point, therefore, is a soil test, which often involves a different type of consultant – often one not tied to a particular fertiliser company. The soil test may be conducted in NZ or may be sent overseas.

Up to 10 to 16 elements are tested for and a programme to ‘balance’ these elements is embarked on. Excesses of elements are looked at as well as deficiencies. This is one of the most important steps to take if you are going to change to organic farming. It is possible with ‘balancing’ to set the soil up with the correct foundations (like the piles for a house) so that when you intro-duce the plants to the soil (put

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the house on the piles) you can get the whole biological system to function better with microorganisms (no good putting the wiring or plumbing in the house if you haven’t got the house built on sturdy foundations). This ‘balancing’ will be discussed in some detail at the end of this section.

• How do you test the soil?Get a soil kit and follow the directions in the kit. For example, Hill Laboratories, 1 Clyde Street, Private Bag 3205, Hamilton, has a very good descriptive pamphlet. A better way is to employ a consultant and get them to take the soil sample as there are a few traps for those that are new to the game. The consultant will want to look at the soil profile, the smell of it, the type and health of the pasture and will also want to look at your animals. A pasture or crop sample taken at the same time is also a very valuable exercise.

• When do you test the soil?As soon as you decide that a more sustainable farming system is the path you want to take. Preferably done in spring or can be done in autumn.

• How often do you test?Initially, it would be wise to do this annually. Some types of natural fertiliser are slow to show up in a soil test so it is good to have a trend and by doing an annual test you will tend to get more information which can help your consultant fine tune your system.

• Where do you send the soil to? There are laboratories in New Zealand and offshore. Some examples are:

Hill Laboratories 1 Clyde Street, Private Bag 3205, Hamilton. Ph: 07 858 2000 Fax: 07 858 2001

Email: [email protected] Web: www.hills-labs.co.nz Brookside Laboratories Inc. New Knoxville, OH 45871, USA Ph: 00 1 419 753 2448 Fax: 00 1 419 753 2949Soil Foodweb Australia 1 Crawford Rd., East Lismore, NSW, Australia 2480. Ph: 00 61 2 66225150 Fax: 00 61 2 66 225 170Soil Foodweb NZ testing contact: Richard and Cherryle Prew 982 Kaipaki Rd, R D 3 Cambridge Ph: 07 827 6682 Fax: 07 827 3787 Email [email protected] Web www.compost-tea.co.nzQuantum Laboratories Ltd 24 Shanley St, Waipawa Ph: 06 857 7333 Fax: 06 857 7999 Email: [email protected] Systems Laboratories P.O.Box 563, Te Puke Ph: 07 573 5998Agri Energy Resources L.L.C. 21417 1950E St, Route 2, Box 113, Princeton, IL 61356 Ph: 00 1 815 872 1190 Fax: 00 1 815 872 1928 Email: [email protected]

If you do not feel comfortable determining your own mineral requirements then find a consultant who can help you do this. That person will have a laboratory they send soil to and whose results they will be familiar interpreting.

• What do I do next?A fertiliser strategy will be set up for you to follow if you do not feel confident in setting one up yourself. You will have to provide a fertiliser budget for your consultant so that a plan of action can be set up (the balancing mineral part of the programmeme may only take a year to do but on some farms it might be as long as 10 years) and each farm will be different. If possible do as much as possible in the first year of conversion.

Step 2: Choose fertilisers which are ‘soil friendly’

There is a change in the type of fertiliser applied when a short-fall is found in a particular element. Sometimes the cheapest source of an element is not actually the best for the soil micro-organisms.

There is a move away from soluble phosphate to a phosphate rock. Farmers overseas have even higher quality products for the soil like Idaho phosphate or North Carolina reactive rock phosphate.

Higher quality lime products are selected. Dolomite is used only if magnesium levels dictate that it is necessary.

Potassium sulphate is used instead of potassium chloride (potash).

Of course if you are converting to organic farming and are going to be certified you will have to consult with your certifying agency and ensure that you use only those products allowable or get permission before you use any restricted fertiliser.

Step 3: Eliminate pesticide and herbicide use

You are not allowed to use any of these products on a certi-fied organic farm but what transitional farmers do is to move from blanket spraying to band spraying and then to spot spraying and at all times trying to reduce the amount of active ingredient going on to the farm by adding products to the spray (e.g. seaweed, molasses, sugars or humic acid solutions).

Farmers notice that the need for pesticides and herbicides decreases as the soil comes into better balance and becomes more biologically active.

Crop rotation and mechanical control are other options for weeds. Timely cultivation can control weeds. Not letting the weed go to seed would be a good goal! There are various machines used for cultivation (e.g. roto-till). Ideally the best one is one that disrupts the weed root and does not beat the soil to death in the meantime. Weed seeds like the stimulation from a dose of sunlight so nocturnal cultivation may be another method.

Some pests or weeds can be controlled by ‘biological control’ like the releasing of natural enemies such as predators, para-sites or pathogens. For example, ragwort beetle for the ragwort weed, a parasitic wasp for a maize-eating caterpillar.

Step 4: Increase the variety of plant species in the pasture and plant trees on the farm

There generally has to be a change in the type of pasture grown, not only for the grazing livestock but to assist with soil develop-ment. (This will usually happen soon after herbicide spraying is stopped!) A pasture that contains only rye or fescue plus a little clover (when it is not eaten by the clover flea and weevil or shaded out by nitrogen boosted rye or fescue) offers little variety to the grazing animal. Each pasture species or herb has a different mineral and trace element profile, different root depth, different growth rates and no doubt an individual taste, not to mention its own variety of microorganisms associated with it! Pastures are often over-sown with a variety of herb species (see Plant section). Many of these have tap roots which enable the plant to source minerals at a depth that the rye and clover roots

cannot get too. These roots also help to break the soil up. An excellent book to read on this aspect for dairy farmers is Newman Turner’s book called Fertility pastures and cover crops (ISBN 0-9600698-6-0).

On those farms where there is no natural shelter nor trees many organic farmers have experimented with non-poisonous tree species for food snacks for stock, a way to stabilise erosion prone soil, to harvest minerals from deeper layers in the soil, to attract bees and birds and to provide another source of organic matter (litter diversity) or leaves to the soil section. (Please see the section on Trees).

Step 5: Nourish the soil microorganismsThis is one of the most important steps and most often underrated or unrealised. There is potentially a huge untapped army of ready and willing workers in every teaspoon of soil if only all farmers could appreciate this and

look after them! These microorganisms need the identical living conditions (to the farmer) to work. They need a comfortable home (soil with the correct minerals, the correct ratio of water and oxygen), they need food (in the form of organic matter), warmth (biologically active soils maintain soil temperature within a narrow range compared to conventionally farmed soils) and freedom from poisons or chemicals. Once the micro-organisms are fed then the crop or pasture will be fed – the microorganisms eat at the table first! This point is important. If you put a lot of organic matter into the top layer of the soil and then plant a crop, the crop will suffer deficiencies, as some nutrients (like nitrogen) will be used by the microorganisms first denying the plant its requirement. You must allow enough time for the organic matter to break down.

Other nutrients or biological stimulants that can be used to feed or enhance the soil life include seaweed (kelp), fish, molasses, sugar, vitamins, humic and fulvic acids, hormones from kelp, paramagnetic materials and biodynamic prepara-tions. It is interesting to observe that a number of farmers who decided to change their fertiliser programmeme often started with seaweed sprays first, noticed benefits from using this and then went on to experiment with the other stimulants. Other options include the use of compost teas, bacterial, fungal or algae, nematode, worm inoculants. It is still important to get the major elements ‘balanced’ first as a lot of these products are used to fine tune the biological system.

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For those farmers who are cropping as well:

Step 6: Change from continuous cropping to a short rotation of crop

Cropping farmers find that if they rotate their crops every year or two there are fewer weed, disease and pest problems. Using a continuous maize crop without a grass or legume green manure crop (one that is grown up to the seed stage and then turned into the top part of the soil) will prevent you from receiving so many of the benefits the microorgan-isms give to the soil.

This is not however a

hard and fast rule as it is possible to grow healthy crops (climax crop) continuously on the same patch of dirt but there can be pitfalls in doing this.

Step 7: The control of the decay of organic matter by the use of tillage to influence the soil to air to water ratio in the soil

Raw organic matter, whether crop stalks or manure, should be tilled into the upper layers of the soil for optimum decay into humus. To leave it on the surface is to lose a lot of the crop residue to the air in the form of water and carbon dioxide

instead of feeding the microorganisms in the soil which can then feed the plants. Any humus that is produced will help improve soil structure making for better aeration and water holding capacity of the soil.

The other alternative is to make compost and apply this to the soil. This is a whole science in itself as no two compost piles will be the same (see later section on Composting).

Some notes on soil balance shared by experienced organic farmers:

• We need a soil system that has the required nutrient elements present in the appropriate amounts and to be available to the plant; we need the physical structure of the soil correct so that our soil food web can function with the lot without hindrance. That isn’t much is it?

• Soil that is left alone goes downhill, even organic land still needs to be fertilised.

• Do not aim to feed the plant. Feed the soil and let the soil feed the plant.

• If the soil is unbalanced, the cow’s dung will be unbalanced.

• Excesses are just as restrictive as deficiencies. You cannot have a deficiency of one element without having an excess of another.

• In terms of nutrient balances, the same principles apply whether it is dairy farming, crop farming, vegetable gardening, vineyards, horticulture or whatever. And the ratios apply whether you are farming in NZ, USA, Ecuador or Timbuktu.

• If the soil minerals are not in balance work on rectifying it.

• Apply calcium (through lime, RPR, dolomite) before you start using liquid fertiliser.

• It is like tuning a violin – get the first four strings right first, by using solid fertiliser, and the fifth string for fine-tuning is the liquid fertiliser.

Biodynamics There are a number of approaches to organic farming. They range from one well-established approach, which are biodynamic methods, through to other broader approaches, where the farmer can choose from a range of possible inputs suited to the individual farmer. The following is a summary of the methods used in Biodynamic Farming.

A help to the farmer and the soil

Biodynamics is a well-tested approach to organic agriculture. In 1993 a major study by Massey University researchers found not only that the financial performance of biody-namic farms was similar to conventional farms, but also that the soil properties were much better. The grower needs organic methods that work, and to know that changing to organics is practi-cally and financially sustainable. Biodynamic methods as an approach to organics, give advantages to the grower. Firstly, they are practical tools for soil management, utilising resources and helping the farmer to practise organics more efficiently. Secondly they give some guidelines to help growers with their decision on changing to organics. It enables them to observe effective changes in soil properties, plant growth and animal health.

Biodynamic farmers and growers have several methods avail-able to them but the most familiar and important are the use of biodynamic preparations. These are small quantities of specially prepared or composted plant and animal parts that have a stimulating effect on the soil and plant. They help to change the soil over time resulting in deeper roots and stronger plants, disappearance of turf mats, better crumb structure with better water transmission and retention (meaning better performance in both wet weather and droughts), more earthworms working deeper, and larger clover nodulation. Overseas research reports of soils managed with biodynamic preparations show great jumps in the levels of soil enzymes. All of this can be summarised in better use of soil resources.

Other tools biodynamic farmers use are the planting calendar, which is based on the planets in relation to the zodiac and our earth (similar to the Maori fishing and planting calendar). They use this to plant, harvest, transplant, spray and do most activities at the optimum time for the benefit of their crop. The calendar is available through the Bio Dynamic Farming and

Gardening Association and is fully explained. Growers can also use RPR, elemental sulphur, lime and other natural minerals if their land shows a need for them. Liquid manures, and composts are also used. Herbs and homoeopathy complement the holistic approach.

Organic growers often say that they need to change the way they think, and that’s the challenge. They have to develop new ways of thinking about their enterprise and this is where the biodynamic approach is a great help. In organic farming the

holistic approach means that the grower needs to take a broad and often a long- term

view – for example anticipating soil fertility issues well ahead,

and managing them before they become problems.

Biodynamics gives guidelines to work with and enhances the soil fertility from the start.

Something important to always keep in

mind;it is optimal to use all the biodynamic practices

and integrate them as they work in together; however, you do not

have to be a biodynamic or Demeter farmer to use these methods. Each one is a tool in its own

right to be used to enhance all forms of organic farming. There are many Bio-Gro certified farmers using biodynamics as well.

The following is a description of the key methods of biodynamic agriculture. Of course the key to successful biodynamics is to put it into practice.

Preparation 500:The most important aspect of Biodynamic agriculture.

• Enhances healthy bacterial activity of the soil.

• Strengthens calcium activity (see Grasp the Nettle, by Peter Proctor, p. 126)

• Encourages strong clover growth.

• Made from cow manure stuffed in a cow horn, buried in the soil over the winter and lifted in the spring. Changes into a sweet smelling rich humus soil-like material.

• Stirred in water for an hour, and sprayed onto the pasture. Only mix the amount that you can apply within an hour.

• Spraying rates are 61.75g, in 30 litres of water per ha, and is commonly reduced for larger areas to half that rate.

• Usually applied during spring and autumn when the ground is warm and moist.

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• Sprayed during a descending period of the moon (marked on the Biodynamic calendar), in the afternoon, so as to improve penetration into the soil.

• Available from the Bio Dynamic Farming and Gardening Association in NZ.

Preparation 501• Preparation 501 works on strengthening the plant and

activity above the soil.

• Helps with photosynthesis.

• Strengthens the plant structure and cellular walls to resist infection.

• Strengthens silica activity.

• Helps plants to resist fungal attack.

• Made from treated silica quartz that is finely ground.

• Stirred in water for an hour, at a rate of 2.5gm in 30litres water per hectare and is commonly reduced for larger areas to half that rate. It is then sprayed onto pasture.

• Applied first thing in the morning in the winter before the sun generates too much heat in it. Usually used in spring and autumn when the grass has grown through a moist period.

• Beware, applying in the heat of the sun, or using excess rates can damage or even destroy your crop.

• Only apply during an ascending period and possibly on or near the moon opposition Saturn (also marked in the Biodynamic calendar)

• Do not apply unless you have applied at least two treat-ments of 500 and the compost preparations previously.

• Available from the Bio Dynamic Farming and Gardening Association in NZ.

Compost preparationsThese are a combination of preparations to enhance usage of the minerals within the soil. They are made cheaply and simply, if you have some experience, or they can be bought from the Bio Dynamic Farming and Gardening Association in NZ for a minimal price.

They are combined to create a balance of activities and can be added to compost heaps, cow manure composts (also known as cow pat pits), liquid fertilisers, liquid teas, liquid seaweed, effluent ponds. They have an amazing ability to convert a mass from anaerobic into being aerobic. It will boil and bubble away, removing any foul smells.

• Preparation 502:

Prepared using yarrow flowers and a stag’s bladder

Enhances the activities of sulphur, nitrogen, potassium and trace elements.

• Preparation 503:Prepared using chamomile plant and a cow’s intestines

Enhances the activities of calcium, sulphur, potash, nitrogen, and oxygen.

• Preparation 504:Prepared using stinging nettle

Enhances the activities of iron, sulphur, potassium, calcium, nitrogen, and magnesium.

Enhances the plants’ ability to take up light.

• Preparation 505:Prepared using oak bark and an animal skull.

Enhances calcium fixing

• Preparation 506:Prepared using dandelion and a mesentery

Enhances the activities of silicic acid and potassium

• Preparation 507:Prepared with the juice of valerian flowers

Enhances the activity of phosphorous, thus helping in the utilisation of RPR

Raises temperatures when sprayed on its own, e.g. in a frost.

The biodynamic calendarThe Biodynamic Farming and Planting Calendar is produced by the NZ Bio Dynamic Farming and Gardening Association in NZ every year and runs from June to May.

It is based on modern research that is still continuing. This research is based on suggestions made mainly by Rudolf Steiner. It looks at the cycles of the moon, the sun, and the appearances through the constellations of the zodiac in our sky and the different influences they have on our planet, the plants and the soil.

The calendar has full explanations on the opposite page about use and symbols that are used on the calendar page.

The main starting points are:

• Descending period (for the moon) for influences

below the ground level.

• Ascending period (for the moon) for things influ-

encing above the ground level.

• Full moon for sowing and drenching.

• There are other times that show the best times to

cultivate to minimise weeds, prune trees, cut hay etc.

The calendar is available to anyone through the Bio Dynamic Farming and Gardening Association.

Cow Manure Composts (Cow Pat Pits)

This is a good way to get full benefit from your compost preparations.

Method:1. Choose a site that is free draining, (e.g. in your vegetable

garden).

2. Dig a hole 600mm x 1000 mm x 150mm deep.

3. Line the sides with untreated timber 300mm in width. Leave bottom uncovered.

4. Backfill.

5. Fill up to 250mm with cow manure, preferably from lactating cows.

6. Add crushed, baked eggshells, and basalt or cut up stinging nettle. Mix well.

7. Insert three sets of compost preparations 502-506 by pressing them into the manure in their own space. Place each one in its own space near the corners and one in the middle.

8. Put preparation 507 in a bucket with a small amount of water and stir for 5 minutes. Sprinkle over and around the edges of the cow pat pit.

9. Cover with hessian sacks to keep it moist and cover with a waterproof lid, allowing water to run off and away from the Cow Pat Pit and air to circulate.

10. Stir around after one month.

11. Should be ready in approximately 3 months.

12. Use the same way as the compost preparations in liquid fertilisers, spraying onto the farm, into effluent ponds etc.

Preparations are also available homoeopathically, but are not approved for Demeter Certification.

Methods of stirring preparations 500 and 501

• The purpose of stirring machines is to create a vortex, similar to that seen in mountain streams, and to interrupt the vortex periodically allowing a few moments of chaos. Therefore a machine must go one way, then change direc-tion to create a new vortex

• There are many different, home built machines made using

paddles and motors with gears. Peter Proctor makes lots of possible suggestions in his book Grasp the Nettle

• Flow forms are available and seem to be the favoured by people with larger farms. Further information is available from: Flowforms Pacific, 83 Endsleigh Rd, R D 2, Hastings, Hawke’s Bay., Phone (06) 877 6914, Fax (06) 877 3943, Email: [email protected], Web: www.FlowformsPacific.com

• For smaller areas use a 200l drum and a 40mm rod or an oar suspended from the rafters, stirring by hand

• Some farmers are using the preparations via decimal homoeopathy. The correct potencies must be chosen. The Bio Dynamic Association does not currently endorse this method.

Tips for spraying • Use a spray tank that has not had chemical sprays in it.

A tank that has previously been used for chemical sprays should be washed according to the directions in the Bio-Gro standards.

• Use a smaller nozzle for preparation 501 than for prepara-tion 500.

• There are good sections on spraying and stirring equipment and methods in Peter Proctor’s book Grasp the Nettle.

There is a booklet being produced and will be available through the Bio Dynamic Association (March 2003)

Contact for preparations and calendars

Bio Dynamic Farming and Gardening Association in NZ P O Box 39-045 Wellington Mail Centre Ph: 04 5895366 Fax: 04 589 5367

Email: [email protected]

Web: www.biodynamic.org.nz

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Composting• Composting is a way of utilising organic matter in a cyclic

method (no waste)

• Can inoculate soil with desirable microorganisms by using compost

• Compost must be good quality to be beneficial for soils and must be made aerobically – in the presence of oxygen at all times

• Compost can be used to make compost tea – a solution that can be sprayed on pasture, crops and trees

There are many text books written on the subject of making compost and research continues to identify ways to improve the final compost product. The reader is encouraged to research the ‘compost topic’ on the internet and read books and journals that have been printed in the last few years. This section is adapted from notes taken by David Larsen on the controlled microbial composting by Siegfried and Uta Lubke in Austria and the soil and foliar foodwebs by Elaine Ingham (See References).

Composting is a useful way of returning organic material back to the soil with a complete array of microorganisms and plant nutrients in an available form (for microbe or plant).

This reminds me of a farmer who brought a farm that had been in continuous maize cropping for more than a decade. He had decided to milk cows on this large block so fenced, raced and built a milking parlour, planted grass and stocked it with bovines only to find that firstly it didn’t grow grass very well and secondly that stock health was appalling. Numerous soil, herbage and blood samples were taken over a couple of years and nobody could put the finger on the problem. All the

soil tests had shown that the required elements were there but still the pasture did not grow even though the farms alongside this farm were growing successfully. A load of chicken manure was ordered and spread over the farm. Within six weeks the neighbours were ringing up to ask what had been done to the farm!

This farm had been sprayed with various products over many years whilst in maize cropping. The microorganism diversity would have been extremely narrow and perhaps even non-existent. What had arrived with the chicken manure were a

set of microorganisms which finally seeded the ground and started the soil food web off again. It didn’t work straight away, it took weeks, but when you think a bacteria can replicate itself into two after 20 minutes and into 4 by 40 minutes, by the end of the day you have a lot present and of course these are moved around by taxi-cabs (insects, hooves of stock, people, vehicles etc.). It would probably not have been the exact or best set of microbes for a pastoral system, but obviously in this case something present is better than nothing and it certainly turned this farm around from being a problem farm to one being profitable again.

The point here is that we can think we have the chemical

balance in the soil correct and the physical structure correct but it is the power of the microorganisms that have the final say. The power of the microorganisms is very easy to overlook - probably because it is not able to be seen by the naked eye nor measured easily to detect whether this living fraction is present or not and whether it is healthy or not. If all else is failing to correct a problem consider the use of a compost tea (see refer-ence section for an excellent manual on compost tea).

Compost can be beneficial for a farming system or it can be neutral or even detrimental. There are quite a few factors which influence the quality of the compost made and whether the final product is suitable for your production system –growing grass or other crops.

It is not sufficient to put a pile of organic matter in a heap and at a later date when it appears to have changed visually, then set about spreading it on your farm. There are numerous cases of this happening and one common report coming back from farmers in New Zealand is that they are noticing earthworm counts are decreasing when they dig up a spade full of soil and do a worm count! This is certainly not a desirable situation.

Compost must be made under an aerobic system - that means in the presence of oxygen! Oxygen from the air is fixed organically. Now the catch here is to ensure that the pile of organic matter is breaking down in the presence of oxygen for the full 6 to 8 weeks or whatever time it takes to get to convert the organic matter to compost. If during the composting process the material becomes deficient in oxygen you will have a putrefaction process occurring – one that draws oxygen from the organic matter instead. You will then have alcohol and formaldehyde type products formed (preservation products or phyto-toxins) and you will lose nutrients from your composting system. None of these events are desirable and every effort must be made to avoid this from happening. In commercial operations oxygen levels are monitored so that this event does not occur.

Compost must reach a temperature that exceeds 57oC for at least 3 days. (Ingham, 2001.) High temperatures are necessary to kill weed seeds and pathogens. This means that the pile will have to be maintained above this for 1 to 2 weeks as the outer sides of the pile will not be at this temperature so will have to be turned in to heat up. This method ensures that all parts of the compost eventually reach that minimum temperature for a minimum of 3 days. The temperature must not exceed 70oC(2).

A temperature probe is often used to monitor the tempera-ture. If you are making compost on your own farm this is one instrument that you must obtain, and use daily to monitor the temperature of your compost pile. If you over cook your compost there is no point putting it out on your soil as it will have detrimental effects on your soil food web.

Making compost requires certain moisture content. Too wet or too dry conditions create improper temperatures. To cool a pile you can turn it slowly, add water or add soil to it. The temperature of a pile will drop 7oC when it is turned.

If a pile is too wet, move it to a new dry mat.

If a pile is too dry, add water or very wet manure.

Did you notice that the requirements for the compost process are the same ingredients humans need for life High tempera-tures are necessary to kill weed seeds and pathogens.- oxygen foremost, water, food and warmth! Although we cannot see these little microorganisms they still have the same requirements as we do and this is no different for those micro-organisms in the soil.

Biodynamic Compost preparations 502–507 inserted into your compost heap will hasten the process and help the anaerobic actions. See the article on Biodynamics.

Parameters measured during compost making

Carbon dioxide

As carbon dioxide is heavier than air it goes to the bottom of the pile. It is a clear odourless gas so the only way to determine if it is present is to measure for it. CO2 is checked at the bottom of the centre of the pile at 6 to 12 inches from

the ground. Aerobic composting uses oxygen and produces carbon dioxide. If the CO2 concentration goes over 20% most microorganisms will be killed off. A build up of CO2 is a sign of a good aerobic process.

If you have low CO2 the compost is

• Finished

• Aerobic

• Dried out too much.

Turning of the compost is required when

• The oxygen is less than 8% or

• Carbon dioxide is greater than 8%.

pH

The pH of a compost pile will rise above 7 or 8 on the second or third day. It will stay above 8 or 9 throughout most of the composting process. pH will drop under 8 when the composting process is finished. If it drops below 6 then lime or soft phosphate rock could be added. (Larsen, 1992.) pH can be used as an indication of the presence of biological life.

Nitrogen in compost

Good finished compost will have 0.8 to 2% total nitrogen content. Microbes use up nitrogen as they multiply. In an ideal pile the nitrate (NO3

- ) drops to near 0, then builds very rapidly in the pile during week two. If the carbon to nitrogen ratio (C:N) is very wide 100-150:1, you will not find NO3

- for a very long time. Nitrogen is fixed by good compost and becomes a part of the amino acid complex of microbe bodies. Nitrogen that is fixed is only released when the plant calls for it. This makes for a very healthy plant. Plants actually secrete an acid to signal microbes to make nitrate available to the plant. When plants stop growing they do not signal the need for nitrate nitrogen. Nitrate levels should drop very rapidly in the plant root rhizosphere.

Ammonia (NH3) is produced when the temperature gets too high in a compost pile. Ammonium (NH4+) may be found in compost early in the process. Aerate the pile if this happens. We want less than 2 mg/kg of NH4+ in finished compost. NH4+ should be converted very rapidly to NO3- if a compost pile is working properly.

Snails and slugs are considered to be an indication of the presence of excess NH4

+.

Nitrogen cycle in compost

NH4+ goes to ---> NO2- which is converted to ---> NO3-

Ammonium ion Nitrite ion Nitrate ion

If NO3- gets too high in a compost pile, add water and turn it. This activates microbial life. We do not want more than 30 mg/kg NO3- in summer. It will be less in winter. You should find very little NO2- in a compost pile that is working properly and none in finished compost.

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Sulphide in a compost pile

You should not find sulphides (rotten egg odour) in a compost pile at any time during the composting process. If sulphides are present, other toxins that are more difficult to test for will also be present.

Ways to get rid of sulphide.

• Aerate the pile several times.

• Piles that are too wet or one that was started with a large portion of woody material is often the culprit.

• If you add nitrogen to a woody pile the sulphide will disappear.

Compost pile site• It should be close to the source of the materials to be used

• If large tonnage’s are to be made then leave room for tractors/compost turners etc.

• Slope in one direction only – no side slope. The piles need to run the same direction as the slope so water does not run under the pile.

• Consider a humus sink with plants to catch run-off at the bottom of the site

• Must have access to a good water supply

• Needs a good base that allows turning the pile in all sorts of weather and protects against seepage into the ground.

• Should not be in a hollow where water can collect and turn the lower part of a compost stack anaerobic.

Compost covers

These must be permeable to allow oxygen to enter and carbon dioxide to leave.

They should also prevent water from getting through (excess from rain) and should keep heat in.

Compost pile size

This does seem to be important. 1m high and 3m wide. If you build higher and wider piles you will have to turn it 4 to 5 times a day to keep the CO2 (carbon dioxide) from building up too high.

Compost turning

There are implements that can be driven off a PTO on a tractor – otherwise use a front end loader or by hand. The top of the pile should go to the bottom and the sides worked into the middle.

There are compost turners - the heart of which is a drum. The size of the drum and the tine angle and length are critical since drum design gives the pile its shape. The RPM of the drum must be kept low – excess speed destroys the crumb structure of the compost. Too much shielding of the drum will not allow CO2 to escape from the pile as it is being turned.

The composting sequence

The composting process has a breakdown phase and a build-up phase. The breakdown phase lasts two weeks and is done by thermophile bacteria (ones that like warmth). At day six the temperature should be 65oC. The thermophile bacteria

break down the organic matter and in doing so release heat. These bacteria are multiplying and dividing so need oxygen and water.

The next phase is the build-up phase and this is where there is a bacterial change and mesophile bacteria consume the ther-mophile bacteria. All the nitrogen and carbon that has been broken down is in the thermophiles and when the mesophiles consume the thermophiles the nitrogen and carbon is still retained but there is no release of heat.

After 6 weeks the compost should be 20oC in temperature. If you purchase compost and it is steaming, the temperature is likely to be well above 20oC so that product is still likely to be in the breakdown phase. You should not purchase this product.

Humus

We want a product from compost that makes humus and the humus test is used to determine if a good job was done in the composting process. It is a relative number and it is never given as a percentage as is organic matter (OM). Laboratories reports on compost often quote a figure as OM (e.g.7%OM). This is a reading of the organic matter and is in fact the percentage of food the microorganisms can feed on. Humus is what results at the end of the digestion process of organic matter. These two parameters are two very different things.

If the humus figure is above 90 it is a sure thing the compost is in the breakdown phase. Compost with a humus number above 90 should not be applied to the soil. A humus range of 70 to 90 is a good range for finished product.

A low humus number may mean that it is just getting started, or you have poor quality materials or a poor job has been done on composting.

If the compost process goes too dry even for a period of 1–2 weeks, you will drop the humus number to 20 to 30.

Humus cannot be made unless some clay is added to the compost. This is usually added on the third day. 10 to 20% clay is required.

What does good compost look like?Compost should not be black (burnt).

There should not be compost ulcers – black fluid oozing out of the compost stack.

The temperature should be around 20oC.

The compost should have a crumb structure.

It should smell sweet, like soil in your vegetable garden.

Do not use any compost that smells

Sour Like vinegar Like vomit Like rotten eggs Like urine Like sour milk

The reason for this is that these types of compost will contain phyto-toxic substances that will kill your plant if they encounter any plant surface. This type of compost will have lost nitrogen and sulphur and therefore be of less value to you anyway.

Using compost to make compost tea (see section on Compost Tea)

If you are making compost tea use freshly made compost. In this case, the compost for compost tea should be slightly immature – that means the temperature should be 5 to 10 degrees above ambient tempera-ture. The longer a compost pile sits the microorganisms become dormant and these extract from the compost.

Remember you need fungal domi-nated compost for the compost tea brewer if you are dealing with trees and a bacterial dominated one if you are trying to grow grass.

To make a bacterial dominated compost it is necessary to start with the right proportion of raw ingredients – nitrogen containing organic matter (manure), green and woody. (Ingham, 2001 b.) It would also be prudent to know where the raw ingredients originated from. Collecting and using raw organic matter like cow manure when the cows have had anthelmintics or antibiotic treatments or grass clippings that have had broad leaf herbicide sprays applied are not suitable as some of the chemicals used in animals and on plants remain active and continue their action during composting. Any raw organic product that contains a preservative is not suitable for composting (Ingham, 2001b). So, this means any product that is used to kill microorganisms. Hence the reason for organic certifying agencies being so strict on the inputs of organic matter on to organic farms. The best source of raw ingredients would be from your own organic farm!

Compost recipe for farmers – bacterial dominated

All the following percentages are % by volume.

25% high N products (see list) – these are needed to make heat in the compost pile.

Have to be careful with the products content of salt, antibiotics and heavy metals.

Legumes – make sure that nodules are present otherwise these products will not be high nitrogen.

Animal manuresFresh ruminant (cow, sheep, goat)

– 25% of the pile by volume

Old ruminant – will have to have a higher percentage of the manure for the pile

Fresh poultry – make this only 15% of the pile as it has higher N

Pig manure – only make this 5% of the pile as it is very high in N

Cow < poultry < pig = human

45% green – examplesGrass clippings, lettuce leaves, fish

Coffee grounds

Sugar beet

Potatoes

Pulp from fruit

Cabbage leaves

30% woody – examplesPaper

Cardboard

Soft coal

Old stumps

Old wood

Sawdust (untreated)

Dry straw

Bark

Sourced from notes given at the biological farming workshop in

2001.(Ingham, 2001a, b.)

Summary of testing parameters for a compost file(Larsen, 1992.)

pH 6.5–7.5 (if higher don’t buy the compost)oxygen not under 8% carbon dioxide not over 8%ammonium NH4+ not above 2mg/kgnitrate NO3- not more than 300mg/kg in summer, 50- 100mg/kg in winternitrite NO2- zero in finished compostsulphide H2S zero at any time during compost processrH (redox potential) 25–28 on finished produchumus value 60-80

Carbon to nitrogen ratio of various compost materials(Larsen, 1992.)

High nitrogen materials C: Nactivated sludge . . . . . . . . . . . . 6 : 1alfalfa . . . . . . . . . . . . . . . . . . . . 16–20 : 1legumes . . . . . . . . . . . . . . . . 10 : 1animal tankage . . . . . . . . . . . . 4 : 1blood or bone meal . . . . . . . . 3 : 1box stall manure . . . . . . . . . . . . 30 : 1coffee grounds . . . . . . . . . . . . 20 : 1cow manure . . . . . . . . . . . . . . . . 18 : 1fruit wastes . . . . . . . . . . . . . . . . 35 : 1garden weeds . . . . . . . . . . . . 19 : 1grass clippings . . . . . . . . . . . . 12–25 : 1horse manure (fresh) . . . . . . . . 25 : 1horse manure with bedding . . . . 30–60 : 1kitchen garbage . . . . . . . . . . . . 23 : 1liquid manure . . . . . . . . . . . . 11–14 : 1liquid sludge. . . . . . . . . . . . . . . . 10 : 1municipal garbage . . . . . . . . 15 : 1paunch manure . . . . . . . . . . . . 10 : 1pig manure . . . . . . . . . . . . . . . . 5–7 : 1poultry manure(fresh) . . . . . . . . 10 : 1poultry manure(with litter) . . . . 13–18 : 1seaweed . . . . . . . . . . . . . . . . 19 : 1slaughterhouse wastes . . . . . . . . 2 : 1urine . . . . . . . . . . . . . . . . . . . . 0.8 : 1vegetable wastes . . . . . . . . . . . . 12–20 : 1

(note: under an organic certified farm a lot of these materials would not be able to be used)

High carbon materials (Larsen, 1992.)

corn stalks . . . . . . . . . . . . . . . . 60:1bark . . . . . . . . . . . . . . . . . . . . 100–130 : 1fresh sawdust . . . . . . . . . . . . 500 : 1leaves . . . . . . . . . . . . . . . . . . . . 30–80 : 1lumber mill wastes . . . . . . . . 170 : 1oat straw . . . . . . . . . . . . . . . . 50 : 1paper . . . . . . . . . . . . . . . . . . . . 150–200 : 1pine needles. . . . . . . . . . . . . . . . 30 : 1rotted sawdust . . . . . . . . . . . . 208 : 1rye straw . . . . . . . . . . . . . . . . 65 : 1wheat straw . . . . . . . . . . . . 125 : 1

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Compost tea• Compost tea is an extract of a sample of compost that has

come from a ‘brewer’

• Compost tea is a method of re-introducing soil biology back into the soil or on plants

• Has to be made specifically for the crop or pasture needed to be grown

• Can be used instead of making huge quantities of compost in the case of large farming operations

• Has the ability to use nature’s own ‘biological warfare’ to control diseases in crops and pasture

• Is another way of providing nutrients to plants using ‘nature’s way’ rather than force feeding via the conven-tional way.

What is compost tea? It is a water extract of a sample of compost that has come from a ‘brewer’. This water extract ends up containing a huge array of organisms from the compost, which range from bacteria and fungi to protozoa and nematodes.

The process starts by first making a compost (see Compost section) and then a sample of this is taken and added to a brewer along with an uncontaminated water source, oxygen (bubbled in) and soluble food (sugar, kelp, humates etc.) to feed all these little critters. So what happens then is that these microorganisms multiply, grow and even die to feed the next group and this is done for a set time until this solution is diluted with fresh water and then immediately sprayed on the pasture, fruit tree, vine-yard or vegetable crop or whatever it is you want to treat.

This method then supplies a huge diversity of the various bacteria, fungi, protozoa and nematodes to your crop, tree, pasture etc. This is a method of returning diversity back to the environment after toxic insults – like chemical sprays, adverse fertilisers, herbicides etc.

The reason behind using a compost tea is to negate or actually remove some of the problem diseases or ailments in a crop by putting a set of diverse microorganisms back into the environ-ment so that a ‘ bug balance’ is attained again.

When and why to use compost tea?It is now thought that every chemical-based pesticide, herbicide, fumigant and fertiliser tested harms or outright kills some part of the beneficial life that exists in soil.

If this is in fact true then there could well be benefits for all farmers to use compost tea on their farms.

When do we use compost tea?If we have had chemicals applied to a crop or farm then there will be benefit from using a compost tea after these chemicals.

If we have a disease in a crop then the use of a compost tea might be indicated.

A compost tea may be applied to prevent a disease in a crop from occurring.

If you are downwind of a neighbour spraying herbicide/pesticide etc. then you can immediately replace the microbes that have been removed by the spray drift by applying a compost tea.

A compost tea applied to all the foliage (and soil on a farm), made from the correct compost for your farming operation, will accelerate the conversion from conventional farming to organic farming.

Why do we use compost tea?We use compost tea to add a huge diversity of microorgan-isms back on to the soil and plant or place the compost tea is applied. We want 70% of the leaf area covered with beneficial microorganisms. (Ingham, 2001a). It is critical that the compost used to make the compost tea is well made and matched to the product you are growing. For instance, if you want to grow grass the compost must be a bacterial dominated type whereas if you are growing grapes or tree crops then a fungal dominated compost type is required. The starting ratios or ingredients for these two types of compost are quite different.

The benefits of using a compost tea can include the following:

Some of the benefits recognised include an ability to spread a small amount of compost over a large area, plant disease suppression, providing plant nutrients, increased nutrient cycling due to the presence of more microorganisms, reduced need for fertilisers and of course a reduction in the need to apply chemicals.

It is not within the scope of this Guide to detail how to make compost tea but this is an area that can be looked at if there is a problem with a crop, whether it be pasture, fruit, vegetable or nut that all other attempts to rectify have failed. This is just another tool that can be used if it fits in with your farming ‘system’.

If you would like to make compost tea then the detailed information about the techniques can be found in Elaine Ingham’s publication The Compost Tea Brewing Manual. See reference section.

Are there places to test the quality of compost tea before application?

Yes!

Soil Foodweb Institute Pty. Ltd, in Lismore, Australia. Samples must arrive within 3 days of sampling otherwise the results will not be representative of the compost tea.

Soil Foodweb Institute Pty. Ltd. 1 Crawford Road. East Lismore, NSW Australia 2480 Ph: 02 6622 5150 Fax: 02 6622 5170 Email: [email protected] Web: www.soilfoodweb.com

They have a laboratory in New Zealand also:

Soil Foodweb contact:Richard and Cherryle Prew 982 Kaipaki Road R D 3 Cambridge Ph: 07 827 6682 Fax: 07 827 3787

Email: [email protected]

Web: www.compost-tea.co.nz

Information: [email protected]

Brix %• Farmers can monitor improvement in pasture and crops

by taking a Brix reading from the sap squeezed from the plant put on a refractometer

• Higher Brix readings in plants mean higher quality produce and more efficient use of this food by animals

• High Brix testing crops will resist insect damage and frost damage and will store longer than low testing plants or crops

• Brix readings are quick to do and the cost is in ‘time’ once the instrument is purchased.

Brix is measured with a refractometer. Dr Carey Reams devised

a chart that shows how fruits, vegetables and grasses can be ranked as either poor, average, good, or excellent based on their Brix measure. Brix % is a measure of the dissolved sugar content of the sap of the plant being tested.

The refractometer reading is only an indirect measure of the soil’s fertility and condition. This instrument can be used to measure the dissolved sugars (technically, the soluble solids which will include minerals, vitamins, sugars and amino acids) of the juice or sap of plants.

How to test for Brix?The plant is squeezed in a tiny press, garlic squeezer or other device, and the drop or two of sap is put onto the surface of the refractometer, the lid closed and this instrument is turned towards a light source and by looking through the eye-piece the reading can be taken. The upper region will be blue in colour and the lower area is white and where the intersection cuts the scale is the value of the Brix % for that sample.

What do the Brix readings mean?Generally, the higher Brix reading indicates a healthier plant growing on good, fertile soil. However, there does need to be some consideration given to the situations prevalent at the time of testing. A low sugar reading may indicate cool temperatures; cloudy weather and young plants can test low. It is important to test the same part of the plant at a similar time of the day in the same weather if you want to make daily comparisons – since all of the above affect photosynthesis or sugar content.

Normally the readings will be highest at midday. They will be lowest in the morning. A high reading in the morning may indicate a sick plant, as there may be a problem translocation sugar from the leaves to the root the way it should.

As a general rule, a Brix reading below 6 is considered poor for most crops and above 12 is considered excellent. Brix for pastures should be 12 or above if possible.

There are some who believe that when the sugar readings are above 12 Brix, the crop will not be bothered by insect pests and in many cases this does seem to hold true, but if a plant is dehydrated the Brix reading will be elevated and hence will not be a true reading.

Why consider using a Brix measure?

Sending plants off to a laboratory for analysis does give excel-lent information but if you want to regularly test a crop or

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pasture then monitoring Brix readings might be considered. A refractometer reading only takes a couple of minutes to do, and a sample of a crop or fruit can be measured each day to observe trends if you are dealing with a valuable crop or you want to determine whether inputs you are using are working. This method costs nothing after the initial outlay for the purchase of a refractometer which costs around $300 + GST in New Zealand.

The testing of crops, pasture, fruit etc. is just another way of monitoring changes happening on a farm. It is just another tool that can be used.

Is it worth Brix testing weeds?Any plant can be tested and you might be surprised to find that so called ‘weed’ species have higher Brix readings than the so called good plants in a field. Generally, as a farmer turns his or her soil over towards better ‘balance’ and looks after the soil food web by not applying herbicides or soluble fertilisers, there will be a trend for the weed species to be not so prolific and the Brix readings will drop in these plants and the pasture species Brix readings will tend to increase.

Additional notes on Brix readings The darker the demarcation between the upper blue and the lower white area, the lower the calcium levels. Thus, samples with same Brix may have different taste due to acidity.

The fainter the line between the upper blue and the lower white area, the sweeter it will be at that Brix.

Plants with the same Brix, but with higher pH will have a higher yield and be sweeter.

Brix testing of silageYes, even silage can be tested. This is a cheap easy quick way to see what potential you have in a silage crop.

Brix % Result4 no fermentation4–8 poor fermentation 8–10 good fermentation10 increased feed value with inoculant

20 optimum feed.

Refractive index of crop juices (Brix %)

Grasses Poor Average Good Excellent

alfalfa 4 8 16 22grains 6 10 14 18sorghum 6 10 22 30ryegrass 6 8 10 12

Source of refractometersBell Technology – John Butler Range from 0–32% Brix model RES Series Ph: 09 5251875 or Fax: 09 525 1874

Effluent as a fertiliserAll certifying agencies encourage the return of effluent to the land. There will be some exceptions to the rule, depending on where your farm is in relation to sensitive areas, but the majority of farms should be able to meet this requirement.

The rule of thumb is ‘… with the intention of spreading surplus manure from organics production. The maximum limit of 170 kg of nitrogen from manure per year per hectare of agricultural area…’. (AgriQuality, 2003.) This is also a reflection of the rules from Bio-Gro and Demeter. Regional Councils have permitted levels that range from 150–200kg nitrogen per hectare per year, depending on the climate and sensitivity of the region.

150kg nitrogen (N)/Ha/Year equates to 37,000 litres/Ha, or 2 milking cows per Ha, or 33mm of effluent.

Benefits as a fertiliser:• Effluent is a valuable resource that completes the nutrient

cycle.

• Effluent returns valuable fertility and organic matter to the soil.

• Effluent improves water retention ability, aeration, draining and friability of the soil.

• It helps create darker humus soils, which warm up faster.

• Effluent has available N P K S and trace elements.

• The organic matter in effluent encourages microbial and earthworm activity.

• Nitrogen is applied in two forms: 50% ammonia, which is available immediately, and reacts similar to urea; and 50% undigested proteins and molecules and is in slow release form.

Nutrient from effluent (kg/year) from herd of 100 cows

Kg/Ha: 590**(N) 70 (P) 540 (K) 50 (S)

** applying this amount over an area of 4 Ha is = to applying

150 kg N/Ha

Sourced from Dexcel, 2003

Percentage of nutrients available in the first year N P K

50% 50% 90%

Other Factors:• Nutrient value varies at the time of the year, and the area

you are in. It is related to the type of feed and soil proper-ties.

• At 37,000 litres/Ha/year, based on average Waikato dairy data, this would deliver 150kg nitrogen, 25kg Phosphate (P) , and 105 kg Potassium (K)

• Effluent should remain in ponds 60–90 days minimum.

• There are nutrient losses during storage and spreading through leaching and evaporation.

• The type of soil will depend on penetration.

• Poorly treated pond and incorrect application can lead to bad bugs on pasture, such as e coli and faecal coliforms.

• Over time land application of effluent increases potassium (K) levels in pasture and soil in the spring and can cause related metabolic problems. To avoid, monitor your potas-sium levels.

• The pH needs to be monitored and it must remain above 6.5. Add lime to correct it.

• Soil test the area after application to ensure a balance is being achieved.

• Spread at a time of year when rainfall does not exceed evaporation to avoid run off and leaching.

Other information in this Guide:Utilising Dairy Effluent in The Environment Chapter.

Planting around Ponds/Dams and Effluent Ponds in the Environment Chapter.

Wetlands Plantings in the Environment Chapter.

All regional councils in NZ are helpful – contact your local one.

Seaweed and fish fertilisersWith traditional fertilisers there are only a handful of elements that are being applied to the soil. Apart from carbon, hydrogen and oxygen, only 14 elements are addressed in agriculture by consultants, namely N, Fe, Mn, Zn, Cl, Ca, Mg, S, Mo, Cu, B, P, Co & Si. It has been reported that the very first cell that sprang from the Precambrian Ocean contained 77 minerals. When one considers that nothing in nature is an accident it is a safe bet to assume that the other 60 minerals play some as yet unidentified role in cell nutrition – whether is is a plant, animal or human cell. No doubt in the future these roles will be revealed by scientists but why wait for science to catch up?

We could try and grow the roots of our plants to bedrock or parent material so that some of these elements can be acquired, but unfortunately there are few pastures that have roots below half a metre let alone many metres to get to the parent material.

If these elements are not present in the bedrock, nor applied to the soil or pasture how do plants or animals get access to them?

Any product derived from the ocean contains the full spectrum of elements, as these elements are all present in seawater. There are, therefore, many benefits to be had by giving a farm an application of a liquid seaweed or fish solution. Not only are you applying a balanced solution with the elements already in an organic form, which are more plant available, but you are supplying some of the trace elements and a food source as well. These products supply complex carbohydrates and proteins and amino acids.

Seaweed products have other benefits. Along with up to 50 elements concentrated from seawater there are other plant stimulants. Cytokinins, gibberellins and auxins are plant stimu-lants, which particularly encourage root development, fungal resistance and rapid cell division during the formation of fruit, root crops, flowers etc. Phenolic compounds add to the effect of cytokinins encouraging cell division but particularly add to resistance to fungal attack. These products are food for the microorganisms in the soil as well as a mineral supply for the plant and microorganism alike.

Those farmers who have used these products have noticed significant improvements in many aspects of their farming enterprise. Veterinarians often note that health problems on farms where a seaweed or fish application programme is being run tend to reduce as well.

In the transition period to organics many farmers have reported using a number of fish and seaweed applications during the year and are reporting good results.

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SourcesThere are many sources of products – a few suppliers are listed below. You will have to confirm whether the products you wish to use are certified by your certifying agency.

Ocean Organics –

www.oceanorganics.co.nz Ocean Organics Ltd 4 Fraser Street, Paeroa, New Zealand Ph: 07 862 8424 Fax:07 862 8404

Garuda P.O.Box 385, Te Puke, Bay of Plenty Phone: 07 573-5859 Fax: 07 573-5839

Email: [email protected]

Web: get.to/garuda

Agrissentials Ltd 122 Lochhead Rd., R.D.6, Tauranga Free Phone: 0800 843 539

Email: [email protected]

Sealord – Nelson for fish Free Phone: 0800 10 60 90

Betta Crop Organics P.O.Box 9024, Hamilton

Tel: 07 824 4881

Rates:Follow the application rates listed for each product.

Making Liquid FertilisersLiquid fertilisers can be a combination of or quite specific:

Seaweed

Fish

Liquid Compost

• Fish is full of trace elements and stimulates nitrogen.

• Seaweed contains trace elements and stimulates potash.

• Compost provides potassium and other minerals, depending on your plants.

These fertilisers are a very important part of organic farming to condition your plants and soil. They encourage the plants to grow and the soil to build up humus. Regular applications are recommended.

There are several products on the market.• Please ensure what you use is certified organic before using.

• Get a letter of confirmation from the manufacturer.

* Biodynamic (Demeter) farmers must put the compost prepa-

rations in the drums six weeks prior to applying to the land

(2 sets per 200litre drums). A further biological reaction

will take place during this time and you will see a lot of

bubbles produced.

Alternatively, you can make your own.• Use a clean holding vessel – drums, vat, tank.

• For fish fertiliser, put a tap or hose at the base, or use a sieve

to filter the liquid out when ready to use, as all the solids

float.

• Gather materials – seaweed, fish, or herbs and weeds and

put into the container.

• You may wish to have one container for each or put it all

together.

• Top up with water and allow to steep for up to six months.

(fish – 6 months, seaweed – 2 months) Stir occasionally.

• You can add the biodynamic compost preparations to help

the biological processes and also to remove the smells.

Available from the Biodynamic Farming and Gardening

Assn at www.biodynamic.org.nz

• Dried seaweed is available commercially and can be used.

• If collecting materials, ensure there is no contamination

(pollution from run off etc). Record and describe where you

collected it and possible pollutants.

• If buying-in materials, (e.g. fish from a fisherman), get a

certificate from the person, describing the product and

guaranteeing there are no contaminants.

• Apply fish at 1–3 litres per HA with water; seaweed at 6–10

litres per HA with water. Ideally you would apply at least

three times a year when the grass is having growth spurts.

• The seaweed could also be used as a drench or in troughs

for animals if it is good quality.

• Liquid composts can be made from any plant (that means

you are returning the mineral they contain back to the

land), (e.g. thistles, ragwort, nettle, blackberry). Others are

herbs you have growing (e.g. comfrey, tansy, fennel etc).

Once again, all plants have high potassium levels and a

balance of other minerals that you farm will benefit from.

VermicastContributed by: Perry Environmental

Vermicast is quite simply worm farming. This means compost worms are turning organic waste, like cow manure, green waste into ‘vermicast’ within a farming situation.

The importance of earthworms to a healthy and productive soil ecosystem has been known since the times of the ancient Greeks. Darwin recognized their importance and commented on them in The Origin. Earthworms improve soil structure, aeration, and drainage by their burrowing. However the degree of importance of earthworms, their activities and in particular their by-products (vermicast) to the soil is only now

been understood fully. The cast they produce is of significant importance to the soil. The digestion of organic matter and minerals produces vermicast by earthworms. It is now known that vermicast is responsible for

§ Improved plant nutrition

§ Improved microbial life

§ Improved soil structure and pH

§ Increased humic acid levels within the soil.

Vermicast is a high-grade organic fertiliser, which offers much more to soil health, plant and animal productivity than tradi-tional inorganic fertilisers.

What is vermicast?Vermicast is produced by the feeding action of earthworms. During normal burrowing and feeding, earthworms ingest organic and mineral matter, fragmenting and grinding it into a finely divided peat like material with high porosity, aeration, drainage and water holding capacity. (Subler et.al, 1998.) This process enhances microbial activity, and accelerates the rate of decomposition of the organic material leading to a humifica-tion effect where unstable organic matter or decomposing plant and animal matter is oxidized and stabilized. Humus forms the dark brown or black mass of the upper soil and is important for storing and releasing plant nutrients. The process is similar to composting except it is non thermophilic or a cold process. Vermicast has a large surface area and a high cation exchange capacity providing strong absorbability and retention of nutri-ents. (Subler et.al, 1998.) As a fertiliser, vermicast contains nutrients in a form that are readily taken up by plants, such as nitrates, exchangeable phosphorous, soluble potassium, calcium and magnesium. (Orozco et al, 1996.)

Table 1 Chemical make up of a sample of vermicast (this will vary)

pH N P K S Mg CaCEC(ME/100g)

Organic Matter (humus)

6.6 2.3 3.0 0.6 0.1 0.65 8.6 52.75 20%

Trace elements Amount ppmZinc 132 Copper 50Manganese 120Sodium 250Boron 110Iron <20

Microbially, vermicast contains a far more diverse microbial population than other composts. Microorganisms play an important part in soil fertility; they not only mineralise complex substances into plant available nutrients but can also synthesize a whole series of biologically active substances including plant

growth regulators such as auxins, giberellins and cytokinins. Auxins are responsible for cell elongation, cytoknins for promoting cell division, and giberellins for stem elongation. These hormones are dose significant and play a fundamental role in plant metabolism. They can influence plant growth and development as well as crop quality significantly when present at very low concentrations. (Atiyeh, 200a.)

Table 2 Biological make up of a sample of vermicast (this will vary)

Biological make up of Vermicast (typical sample of Perry Vermicast)

Total Bacterial Mass μg/g 249Total Fungi Mass μg/g 238Flagellates(#/g) 11772Amoeba(#/g) 94235Ciliates(#/g) 2836Total no Nematodes (#/g) 185

The ability of vermicast to influence plant growth is a reflection of the parent material the earthworms are composting.

How does it work?Until recently scientific documentation of the growth responses of plants to which vermicast has been applied has been minimal, even though anecdotally positive evidence has been abundant. Over the past five years the soil ecology laboratory at the Ohio State University has developed a comprehensive research programme in vermicomposting. Key findings from their research have found that:

§ The addition of vermicast as a fertiliser or as a compo-

nent of horticultural bedding mixes has resulted in dramatic

improvements to plant growth.

§ Vermicast improves the aeration and water holding

capacity of soils.

§ Vermicast has been proven to have natural antibiotic

properties and suppress certain plant diseases and plant-

parasitic nematodes.

§ The addition of vermicast will increase the diversity and

number of soil arthropods in the soil improving nutrient

cycling.

§ Vermicast improves Brix readings (sugar levels) in the

pastures and crops it has been applied to.

§ The growth benefits of vermicast can be gained from

using relatively small percentages of vermicast 30–50%.

When blended with other fertilisers, i.e. RPR, Lime, chicken

manure or composts, vermicast enhanced the performance

of these products significantly.

§ The addition of vermicast greatly promotes root growth

and the ability of plants to uptake nutrients.

§ Vermicast promotes mycorrhizal fungi growth.

§ Improves the availability of nutrients to plants.

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The low % of castings required to produce a dramatic plant growth response indicates that the growth responses are more than simply a function of supplying plant nutrients and that other related growth stimulants are involved. (Subler et.al, 1998.)

Scientific testing has now proven that the addition of vermicast consistently improves seed germination, enhances seedling growth and development and increases plant productivity much more than would be possible from the mere addition of plant nutrients (NPK). (Tugel et al, 2000.) Research has identified two important attributes of vermicast; humic acids and microbial populations.

Humic AcidsEarthworm derived humic acids are produced by the breakdown of organic matter by the micro-organisims found naturally occurring within their digestive system. This breakdown by earthworms accelerates the humification of organic matter. The humic acids produced in this process are large complex molecules. Partial oxidation of humic acids allows bonding sites for plant nutrients including calcium and magnesium, and other humic–like materials produced in the faeces of earthworms which exhibit auxin, gibberellin and cytokinin like activities. (Nardi et al, 1988.) Studies of the positive effects of these humic substances on plant growth when full requirements for mineral nutrition are met resulted consistently in positive effects on growth independent of nutrition. (Atiyeh et al, 2000b,c.)

Humic acids have been reported to enhance mineral uptake by plants by increasing the permeability of membranes of the root cells. (Atiyeh et al, 2000b,c.) Vermicast humic acids appear to have greater effects upon the root growth of the plants than on the above ground parts of the plant. Stimulation of root growth, increased proliferation of root hairs, and enhancement of root initiation by humic acids have been reported commonly by several other researchers. (Atiyeh et al, 2000b,c.) Humic acids are also important in de-compacting soils, and their complex molecular shape replaces sodium and Aluminium ions, which become trapped in between clay platelets compacting the soil. (Bio Ag Technologies International, 1999.) This action also helps liberate trapped phosphate, which is insoluble when associated with sodium and Aluminium.

Improved plant nutritionVermicast improves nutrient availability for plants in a number of ways. Vermicast is nutrient rich itself containing many macro and micro plant essential nutrients. Vermicast also improves soil conditions by improving the pH of soils it is added to and by adding essential soil microorganisms. The microbial populations living within them control nutrient cycling within the soil. (Edwards, 2003.) The diverse make up of the microbial communities existing in vermicast play an important role in soil fertility, breaking down organic matter, and the different substances found within the soil from simple sugars to complex substances and inorganic nutrients, into plant available forms. (Tugel et al, 2000.) If any are missing plant growth and health will be inhibited. Vermicast is rich in mycorrhizal fungi spores, which form the network between roots and nutrients within

the soil. Mycorrhizal fungi have been identified as important for mobilising locked phosphate within the soil and transporting it to plant roots. (Edwards, 2003.). The addition of vermicast also encourages the colonization of nitrifying bacteria within the soil. Many nitrifying bacteria are found in close association with plant roots, particularly legumes like clover. (Edwards, 2003.)

Vermicast encourages root growth and colonisation. These bacteria are very important, converting ammonium ions within the soil to nitrate which is plant available. Vermicast also improves the diversity of soil arthropods. These organisms are essential in the nitrogen cycle as they release excess nitrogen in plant available form. In fact the nitrate nitrogens (plant avail-able) in cow manure can increase from 8.8ppm to 259.4ppm when passed through worms.

Application of vermicast to organic dairyingContributed by Perry Environmental and Andy Moser

The use of vermicast as a fertiliser provides farmers converting to organics and existing organic dairy farmers a proven path to follow which not only maintains excellent production but improves soil health, soil structure and natural nutrient cycling. Vermicast enhances the performance of other organic fertilisers when blended with them. Reactive rock phosphate, lime, compost effectiveness are all improved when blended with vermicast to a degree that exceeds that which would be expected by the combined nutrient levels of the two products combined.

Popular blends with vermicast provide the following nutrient breakdowns:

• Combined with RPR, vermicast enhances the citric solu-

bility of RPR by an additional 57% through the microbial

activity provided by vermicast.

• Combined with lime, vermicast helps to liberate calcium

and make it available in your system. Some regard it as

the ultimate soil conditioner and fertiliser. The calcium

combined with the humic acids in vermicast help liberate

locked phosphate and improve soil structure.

• Vermicast can also be combined with compost.

• Vermicast can be applied as liquid manure. Trace

elements can be added to the liquid as chelates.

(Permission must be sought first)

Application:• Keep out of direct sunlight and ideally in moist condi-

tions.

• Extreme heat or cold, slaty, powdery fertiliser can harm

certain organisms e.g. the calcium storing and trans-

porting surface fungi.

• Spray pressure should not exceed 40psi/275kpa

• Human, stock and other crops do not need protection

from spray drift.

• Don’t forget to treat it as a living organism.

• You can target either the leaf or the soil.

• Follow the recommended rates and the handling advice

of individual products, but also trust your own judgment

to make decisions on the day.

Suppliers:Revital Fertilisers (Perry Environmental) Freeph: 0800 367-967

Web: www.revitalfertiliser.co.nz

Bio Liquid Technology 1128 Pyes Pa Rd, Tauranga Ph: 09 578 0707 Fax: 07 543 3305

Email: [email protected]

Web: www.bioliquidtech.co.nz

Worm Tech NZ, Liquid CastingsKevin Massey Freeph: 0800 00 3000

Rock dust• Certain types of rock finely ground can improve fertility

of soils

• Not all types of rock confer fertility.

For those farmers who have access to rock dust this may be another way of improving crop or pasture quality, and for those who have crops sensitive to frost damage then the applica-tion of ground rock in the fertiliser programmeme should be considered. It does pay to be aware of the constituents of the rock dust as most rock types can be crushed, but you need to be wary of unwanted heavy metal content.

Available oresReactive phosphate rock (imported – Sechura): calcium and phosphate

Limestone: Calcium

Gypsum: Calcium and sulphur

Dolomite: Calcium and magnesium

Dunite: Magnesium, silica

Talc magnesite: Magnesium

Bentonite: Silica, potassium (as oxide), sodium (as oxide)

Basalt: Silica, trace elements

Granite: Silica, trace elements

‘ROK Solid’ is a product available from Tauranga.

This product is made from volcanic rock which is ground to fine dust. This rock contains over 60 minerals.

Rate: 250kg/ha

SourceLocal quarries with crushers are a good source of material, the fine particles accumulating under the crusher being regarded as a nuisance.

Agrissentials Ltd. for ROK Solid. 122 Lochhead Road. RD6. Tauranga. Telephone: 07 552 4343 Free phone: 0800 843 539

Ask at your local quarry and see if there is fine ground rock available.

Paramagnetic materialThere may be a way of improving the fertility of a soil by adding paramagnetic material. What do we mean by paramagnetic material?

DefinitionsWe will define three types of magnetism so you can appreciate the differences.

diamagnetic – diamagnetic materials are weakly

repelled by magnetic fields.

ferromagnetic – ferromagnetic materials are strongly

attracted by an external magnetic field.

paramagnetic materials are affected by an external

magnetic field because their atoms or molecules line

up with (rotate into a new position) the external lines

of force coming from the magnet. In paramagnetic

materials this phenomenon is weaker compared to

ferromagnetic materials. Paramagnetic materials

are attracted toward magnets, but do not become

permanently magnetised. These materials have

unpaired electrons in the atomic make up which can

be affected by an external magnetic field.

If you have movement in magnetic fields, then by definition and the laws of physics you will have a current induced in any nearby conductor. This opens the door to influence of biological process that depends on ionization (electrically charged parti-cles). This influence sets the stage for paramagnetism of soils to have an influence on microorganism and plant growth. Plants are diamagnetic-repelled by a magnet.

It is the materials that fall into this latter group which we are interested in. Soils that are high in paramagnetic susceptibility tend to be extremely fertile. All volcanic soils and rock are highly paramagnetic (from 200 to 2000 uCGS).

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Paramagnetic force can be added to the soil by spreading ground up granite or basalt.

Mineralisation of the soil by adding separate minerals does not mean paramagnetic force has been applied. The more the mineral diversity and the greater the paramagnetic susceptibility, the greater the absorption of energy by the soil. Compounds of chromium, cobalt, copper, iron, manganese, molybdenum, and nickel all test high for paramagnetism if you consider these as common compounds. What is very notice-able in listings of all the paramagnetic compounds is that the high susceptibilities (strong paramagnetism) are strongly asso-ciated with rare earth and other exotic trace elements. Some of the less pure calcium carbonate lime products available in New Zealand contain minute amounts of these rare earth and exotic trace elements, which may also account for some of the apparent plant growth responses which appeared to be greater than otherwise expected.

Paramagnetism is a geological occurrence in certain mineral complexes that is quite rare and geologically and geographi-cally site specific. It is usually associated with mineral elements that have an odd number of electrons in their outer shell that may also exhibit high density (heavy), variable valence (+2, +3, etc.) and high melting points. Some of these highly magnetic deposits have been mined, screened and sold for application on agricultural soils.

Dr Philip Callahan’s book on paramagnetism is an excellent source of information on this topic. The study of what effects this application has had, as well as study of soils with relatively high natural paramagnetic properties is still in its infancy, but a lot of interest is being shown by growers concerned about sustainable, biological or organic farming.

Paramagnetic susceptibility is measured by a PCSM (or para-magnetic soil meter) and is measured in CGS or centimetre, gram, seconds. Any soil or rock that when suspended moves towards a magnet, is paramagnetic. As a general rule most organic matter and all plants are diamagnetic. Water is diamagnetic. The atmosphere is paramagnetic due to the oxygen content. Oxygen is the most paramagnetic out of all the gases. Nitrogen gas is diamagnetic. The moon is highly paramagnetic and has a strong effect on the tides, which are diamagnetic water.

It is a sad fact that a lot of the paramagnetic material that was present in soil has been eroded away worldwide and

is sitting in the ocean around the landmasses. If you have a situa-tion where crops are failing to grow, insects and disease are devouring what is growing and the soil is well aerated, compost or compost tea has been used and no known herbicides have been used, then have the soil checked for its paramagnetic value. This may be the missing link.

What are the paramagnetic values of rock components?

Some samples of materials from the CRC Handbook of Chemistry and Physics concentrating on the highest paramag-netic values have been listed in the Appendix 8. (This is not a complete list of paramagnetic materials.)

The composition of igneous rock (that which comes from larva or magna – volcanic rock) is listed in the appendix hence the reason for adding volcanic rock to soils in a finely ground form!

What paramagnetic value should my soil have?

According to Dr Philip Callahan’s research, a soil magnetic susceptibility reading of:

0–100 uCGS would be poor;

100–300 uCGS good;

300–800 uCGS very good;

800–1200 uCGS above excellent.

Results seen with adding paramagnetic material to soils

In Australian research on paramagnetism there was a decrease in the amount of irrigation water required to grow crops, there was greater drought and frost flexibility, invigorated chlorophyll production and insect resistance. Water respiration, disper-sion and absorption are greatly enhanced when the soil is aggregated by the magnetic inductance. In forest research, generous applications of paramagnetic minerals produced a heavy mycelium (fungal) carpet that produced nitrogen, poly-saccharides and increased biomass.

Research over the last 10 years in Canada with re-mineralisa-tion of soils with paramagnetic deposits has greatly improved

the nutritive value of crops. In alfalfa there were solid stems, higher protein and digestible fibre, more energy (a higher Brix reading), more diversity of proteins with good enzyme and amino acid profiles all of being observed.

Orchards have responded with a greater diversity of fauna, increased dew points, and improvement in tilth, new root growth, soil aggregation and great tasting fruit.

Direct application and inclusion in the composting process or manure handling pits can all lead to great benefits when highly paramagnetic deposits are used to increase the paramagnetic susceptibility (ability to absorb and use free energy) of our soils. It should be noted that paramagnetic susceptibility can also be increased by soil aeration (oxygen is highly paramagnetic) and by growing a variety of green manure crops like mustard, ryegrass/clover, lupins and tilling them into the aerobic zone of the soil. Each cover crop will attract different minerals into its structure from the air and increase the soil mineral content and diversity when it is incorporated.

A lot more research should be conducted in this area. It would be beneficial to have your soil tested for paramagnetic suscep-tibility first before applying paramagnetic rock. There would be little point in applying paramagnetic material if you already have a high paramagnetic reading from your soil.

SourceYou would have to find a quarry, which deals with basalt or granite. A proprietary product called ROK SOLID is available from Agrissentials and this is a basalt rock that has been finely ground.

Rate: 250 kg/ha

Freeph: 0800 843 539Email: [email protected]: www.agrissentials.com

Other website: www.nutri-tech.com.au/articles/Paramagnetism.htm

Pesticides, herbicides and fertilisers, and the effects on soilAll pesticides, herbicides and fertilisers affect soil micro-organisms to some degree, with some being far worse than others.

Although methyl bromide is commonly used to sterilise soil overseas it kills everything and when most pesticides are compared to this they are not nearly as harmful, but when pesticides are used repeatedly, even though only a few species are impacted upon, the cumulative effect of multiple and repeated pesticide applications has been a loss of the soil’s ability to maintain life.

Fertilisers kill microorganisms typically as a result of osmotic shock (salt effect – see later section). To reduce the effects of salt fertilisers it is best to use small amounts more often rather than one large application and have a healthy food web in the soil to help move those nutrients to the plant.

For more information on the effect of pesticides and herbicides see:

The Bulletin of Environmental ToxicitySoil Biology and BiochemistryApplied soil ecologyBiology and Fertility of the soilSFI web site – www.soilfoodweb.com - E. Ingham

Salt based fertilisers• A large number of fertilisers are salts

• Salts are harmful to soil structure and soil micro-biology

• Salts are not permitted to be applied to the soil on organic farms.

When we think of the word ‘salt’ we typically think of table salt (sodium chloride). When we look at the chemical bonding of this product we find that the sodium is a positively charged ion (cation) and it has a negatively charged ion of chloride. Technically, if you go back to the science books the definition of a salt is one that is formed when you react an acid with a base. There are therefore a lot of different types of salts that can be formed when you consider all the different acids and bases that could be mixed together.

When we look at types of fertilisers (compounds) applied to soil they have a similar chemical structure like table salt and can be referred to as salt based fertilisers. When you look at potash or potassium chloride, the potassium has a positive charge and the chloride a negative charge. When salts dissolve in water the two ions separate. These can then become available for the plant but if the root doesn’t need the positive ions they can be bound to the soil if there is some exchangeable hydrogen ion present that can be dislodged. If there are no roots, no microbes and no holding sites, these ions can be leached out of the soil along with the negative ions – nitrate and sulphate if they are free.

Salt fertilisers give a quick release of soluble, readily available ions - like giving an steroid boost to the plant.

Too much salt causes an imbalance as we have discussed else-where and is very detrimental to the soil microorganisms.

Phosphate ions can also be tied up very quickly in the soil and become insoluble or unavailable to the plant roots unless made available by the soil microorganisms.

Some salt fertilisers cause a greater drying out effect to roots and microorganisms than others and this is measured by a salt index. A higher salt index indicates greater damage.

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Let’s look at the salt index for some of the common fertilisers that are put on soil:

Fertiliser Salt IndexPotassium chloride (potash) 116.3Ammonium nitrate 104.7Urea 75.4Potassium nitrate 73.6Ammonium sulphate 69.0Calcium nitrate 52.5Potassium sulphate 46.1

Sulphate of potash–magnesia 43.2Diammonium phosphate DAP 34.2Monoammonium phosphate MAP 29.9Triple superphosphate 10.1Calcium sulphate 8.1Superphosphate 7.8Sodium chloride (Salt) 1.0

Source - Zimmer Gary F. 2000. The biological farmer. ISBN 0-911311-62-9

For those farmers who want to gradually wean their farms off the less desirable fertilisers like potassium chloride and urea (both high salt index fertilisers), you can select other types of fertilisers to supply your potassium and nitrogen (for example so as to limit or reduce damage done to soil microbes or plant roots). However, certifying agencies change their policies so you may find that some of these salt-based fertilisers may be permitted so please check with your certifying agency. Biodynamic registered farmers are generally not permitted to use salt-based fertilisers.

Tools of the tradeA refractometer is one of the most useful tools a farmer may use to monitor crops. A good keen nose and a shovel are the most useful. Those other farmers who really want to monitor what is happening with their soil and pasture/crops may consider experimenting with these other instruments.

Believe it or not, four good cheap to run tools to monitor

progress on our farms sit above our necks!

A brain that is thinking, making notes.

Sight – see what it is that you are looking at. Note

changes. It may be the change in structure of the plant, the

disappearance of weeds over time from a paddock that you

are changing the inputs too. Observing more birds, bees

other insects. A change in the behaviour of your animals

etc.

Ears – sound. Yes, you may notice as some biological

farmers have noted, that their cows make a lot more noise

when they are eating pasture as it has changed its compo-

sition.

• Nose - use it and note what the soil smells like

when you pull a plug for the soil test bag or dig a hole or

what the compost smells like when you start to spread it

out.

• Taste may be used but do so with caution. Taste

may be used to monitor food crops but pastoral land can

be contaminated with faeces which could contain patho-

gens (leptospirosis, salmonella etc.)

• Shovel

• Soil probe 0 to 30 inch depth

• Thermometer

• Magnifying glass

• Refractometer - see the section on Brix.

Specialist tools that may be used • Infrared stress meter: for plant stress

• ORP meter: oxidation-reduction potential.

• Penetrometer: soil compaction tool -psi greater than 300 no root penetration

• Nutrient field meters

• PCMS Phil Callahan Soil Meter: measures paramagnetic soil

• Chlorophyll meter: photosynthesis, nitrogen availability

• pH meter: used on sap of plant and soil

• Conductivity meter ERGS: energy released per gram of soil

ReferencesBiodynamics

Bio Dynamic Farming and Gardening Association in NZ P O Box 39-045, Wellington Mail Centre Ph: 04 589 5366 Fax: 04 589 5367 Email: [email protected] Web: www.biodynamic.org.nz

Henderson, G. (editor) Biodynamic Perspectives - Farming and Gardening. Available through Bio Dynamic Farming and Gardening Assn

P O Box 39 045 Wellington MC. Ph: 04 589 5366

Pearce, N. 1993, A Biodynamic Farmer’s Handbook. Available through Biodynamic Farming and Gardening Assn and Touchwood Books. www.touchwoodbooks.co.nz

Proctor, P. and Cole, G. Grasp the Nettle Available through Bio Dynamic Farming and Gardening Assn ISBN 1-86941-318-0

Reganold, J.P, Palmer, A.S., Macgregor, A.N., 1993. Soil Quality and Financial Performance of Biodynamic and Conventional Farms in NZ. Science. 260: 344-349

Steiner R Agriculture. ISBN 0-938-250-35-3 (hardback); ISBN 0-938-250-37-1 (soft bound)

BrixAndersen, A.B, 2001, The management of

Biological Farming (workshop)

Source of refractometersBell Technology - John Butler: 0–32% Brix model

RES Series

Ph: 09 525 1875 or Fax: 09 525 1874.

CompostingAndersen, A.B. & Ingham, E.R. 2001. The

Management of Biological Farming Workshop Manual.

Ingham, E. R. 2001a.The compost tea brewing manual. Second edition.

Ingham, E. R. 2001b. The soil and foliar foodwebs (The management of biological farming workshop).

Larsen, D. A. 1992. Composting. Notes from a study trip to Austria. Siegfried and Uta Lubke.

Compost TeasIngham, E.R. 2001a The Compost Tea Brewing

Manual. Latest recipes, methods and research. 2nd Edition.

Ingham, Dr. E.R. 2001b The Soil and Foliar Foodwebs. (The management of biological farming workshop.)

Larsen, D. A. 1992. Composting. Notes from a study trip to Austria. Siegfried and Uta Lubke.

www.soilfoodweb.com Email: [email protected]

www.sustainablestudies.org

EffluentAgriQuality, 2003. AgriQuality Organic

Standard.

Dexcel, 2003, A Guide to managing Farm Dairy

Effluent by – Farm 4 Tomorrow – environment and animal welfare. Constantly being updated. Version 1.

Lampkin N, 1990 Organic Farming, pub Organic Farming Press, Ipswich UK.

Northland Regional Council – all regional councils in NZ are helpful – contact your local one.

Ravensdown Fertiliser, Aug 2002, Where there’s Muck there’s…grass, Ravensdown Fertiliser Newsletter.

Tanner, Dr C. Research done on APS and wetland systems for effluent by, NIWA. P O Box 11-115, Hamilton. Web:www.niwa.co.nz

Paramagnetic MaterialCallahan, P. S., PhD, Paramagnetism -

Rediscovering Nature’s Secret Force of Growth

www.nutri-tech.com.au/articles/Paramagnetism.htm

Pesticideswww.soilfoodweb.com

Andersen, A.B. Putting Theory into Practice. 2001. Soils and agronomy manual.

Kinsey, N. and Walters, C. 1999. Neal Kinsey’s hands on agronomy. ISBN 0-911311-59-9

Turner, N. Fertility Pastures and Cover Crops, ISBN 0-9600698-6-0

Zimmer, G. F. 2000. The biological farmer. ISBN 0-911311-62-9

Rock DustPearce, N. (1993), A Biodynamic Farmer’s

Handbook ISBN 0-473-01894

Soil and Health Assn, September 1990, Soil and Health Magazine, page 13.

Soil Test Reports and InterpretationsAlbrecht, W.A. Ph.D. (1975) The Albrecht Papers

Volume I. Foundation Concepts Edited by Charles Walters ISBN 0-911311-05-X.

Albrecht, W.A. Ph.D (1975) The Albrecht Papers Volume II. Soil fertility and Animal Health. Edited by Charles Walters ISBN 0-911311-07-6.

Albrecht, W.A. Ph.D (1989) The Albrecht Papers Volume III. Hidden lessons in unopened books. Edited by Charles Walters ISBN 0-911311-18-1.

Albrecht, W.A. Ph.D. (1992) The Albrecht Papers Volume IV. Enter without knocking. Edited by Charles Walters ISBN 0-911311-23-2.

Kay, T. and Hill, R. (1998) Field Consultants Guide to Soil and Plant Analysis.

Sinclair A G et al. (1990) Proc. NZ Grasslands Soc. Vol. 51, 101-104.

The Soil Food WebTugel, Arlene, Ann Lewandowski, Deb Happe-

vonArb, Eds. 2000. Soil Biology Primer. Rev. ed. Ankeny, Iowa: Soil and Water Conservation Society.

The Soil Biology Primer is available at soils.usda.gov/. Look to the left under Quick Access. First click ‘Soil Quality’ then click ‘Soil Biology’

VermicastAtiyeh , R. Edwards, C.Subler, S. Metzger, J.

(2000a). Earthworm- Processes Organic Wastes as Components of Horticultural Potting Media for Growing Marigold and Vegetable Seedlings. Compost Science & Utilisation, Vol8,No 3, 215–223.

Atiyeh,R. Arancon, N. Edwards, C. Metzger, J. (2000b). Influence of earthworm- processed pig manure on the growth and yield of green-house tomatoes. Bioresource Technology 75, 175–180.

Atiyeh , R. Edwards, C.Subler, S. Metzger, J. (2000c). Pig manure vermicompost as a component of a horticultural bedding plant medium: effects on physiochemical properties and plant growth. Bioresource Technology 78, 11–20.

Atiyeh,R. Arancon, N. Edwards, C. Metzger, J. Lee, S. (2002). The influence of humic acids derived from earthworm-processed organic wastes on plant growth. Bioresource Technology 84, 7–14.BioAg Technologies International (1999). Humic Acid Structure and Properties. www.phelpstek.com/graphics/humic_acid.pdf

Edwards, C. 2003. Personal communication.

Nakamura, Y., (1996). Interactions between earth-worms and microorganisims in biological control of plant root pathogens. Farming Japan 30, 37–43.

Nardi, S., Arnoldim, G., Dell’Agnola, G., (1988). Release of the hormone like activities from allolo-bophora rosea (Sav) and Allolbophora caliginosa (Sav.) feces. Canadian journal of Soil Science 68, 563–567.

Orozco, F.H., Cegarra, J., Trujillo, L.M., Roig, A., (1996). Vermicomposting of coffee pulp using the earthworm Eisenia fetida:effects on C and N contents and the availability of nutrients. Biology and Fertility of soils 22, 162–166

Soil and water conversation society, (2000). Soil Biology Primer. Soil and Water Conversation Society USA.

Subler, S., Edwards, C.A. and Metzger, J. 1998. Comparing Vermicomposts and Composts. BioCycle, July 1998. pp. 63-66.

Szczech M., Rondomanski, W., Brzeski, M.W., Smolinska, U., Kotowski, J.F., (1993). Suppressive effect of a commercial earthwormcompost on some nroot-infecting pathogens of cabbage and tomato. Biological Agriculture and Horticulture 10, 47-52.

Tugel, Arlene, Ann Lewandowski, Deb Happe-vonArb, Eds. 2000. Soil Biology Primer. Rev. ed. Ankeny, Iowa: Soil and Water Conservation Society The Soil Biology Primer is available at soils.usda.gov/. Look to the left under Quick Access. First click ‘Soil Quality’ then click ‘Soil Biology’

General ReferencesMcLaren RG and Cameron KC 2000 Soil Science Oxford UP (NZ) ISBN 0-19-558345-0.

Zimmer, G.F. 2000. The biological farmer.