Stephen Briggs

Managing soil biology

Stephen Briggs MSc, BSc, IOTA, Nuffield Scholar

[email protected]

mailto:[email protected]

• Dirt or Soil – What's the difference ?

• Soil life / soil biology

• Feeding soil biology

• Soil analysis

• Practical steps for good soil biological management


What is soil?

Natural SuccessionNatural Succession

“It takes more than 500 years to form an inch of topsoil.” “It takes more than 500 years to form an inch of topsoil.”

No Soil Life

Max Soil Life

Structure and ‘Structure and ‘habitathabitat’ for soil life is important ’ for soil life is important


• Soil life / soil biology – What is it – Different types – The soil food web and how it works – The benefits of the soil food web – What is needed for good soil biological life


• Soil analysis



Plant roots move to nutrientsPlant roots move to nutrients Nutrients have to be ‘Nutrients have to be ‘processedprocessed’ to be ’ to be made plant available (by soil microbes)made plant available (by soil microbes)

Nutrients need processing Nutrients need processing into available forms into available forms

for plant uptake for plant uptake

(by soil microbes)(by soil microbes)

FertilisersFertilisers

Soil life Easily seen

Soil life hidden

Soil Soil Food Food WebWeb

But what about the impact of pesticides and But what about the impact of pesticides and fertilisers on the soil microbial food chain ?fertilisers on the soil microbial food chain ?

Above ground

Plants more tolerant of salts Soil animals and microbes damaged / killed by salts

All have salts

Mycorhizae

• Myco = fungus rhiaze = root

• More than 90% of plants have a mycorrizal symbiont

• Ectomycorrhizae (external)

• Endomycorrhizae (internal)

mycorrhizae

Mycorrizal Fungi hair like filaments (hyphae) bind soil particles together, helping create friable structure soil

Do Fungicides effect Mycohorizae ?

•Foliar applications of non systemic fungicides have less effect even though some reach the soil •Soil applied non systemic fungicides can inhibit VAM – esp when roots small at low colonization rates •Greater impact on ‘ecto’ (outside) VAM than ‘endo’ (internal) VAM •Systemic fungicides generally inhibit VAM •Fungicidal seed treatments = varied impacts •Choose Fungicide carefully !



• Feeding soil biology – What kind of feed – When – how

• Soil analysis



Crop needs

Soil ‘livestock’ needs ?

Material C: N ratio

Soil microorganisms 7

Soil organic matter (SOM) 10 – 12

Clover 13

Compost 15

Grazing Rye 36

Maize stems 60

Wheat straw 80

Fresh sawdust 400

Soil Organic Matter

Decline in mean soil organic carbon concentration (% g Decline in mean soil organic carbon concentration (% g gg--11) for UK loam soils (1.3 ) for UK loam soils (1.3 MhaMha). ).

2.18

2.2

2.22

2.24

2.26

1930 1940 1950 1960 1970 1980 1990 2000 2010 2020

Year

SO

C (

% g

g-1

)

MC1

MC7

MC1 = from permanent grassland MC7 = cultivation Dotted lines beyond 2000 represent projections assuming no further management changes (Source : Canfield University Defra Project SP0553 2003)

2.24 2.24 –– 2.00%2.00%

= 11% loss= 11% loss

English soil SOC concentrations

= 1.3% (g g-1) Red pixels = 2.3% (g g-1) Green pixels = permanent grassland & native vegetation

Arable sites tending to 1.3% Carbon

Arable sites tending to 2.3% Carbon

Pemanent grassland

Other landuses (not arable or permanent grass)

Arable sites unable to classify

(Source : Canfield University 2013)

In natures termsIn natures terms

“Cultivation is a catastrophic event !”“Cultivation is a catastrophic event !”

Soil Organic Matter

Feed soil life




• Soil analysis – What standard analysis is tells you (and not) & what its for – Other information – Approaches for soil biological management



Standard Index

Soil Analysis

Standard, Macro, Trace & Base Saturation

Soil Analysis

Soil biology Analysis




• Soil analysis



Suppression of plant pathogens

Improved soil structure and water retention

Greater diversity of soil organisms

Supply of plant nutrients

Some benefits of compost

Typical nutrient content Green waste compost

Material DM

(%)

Total

(kg/t fresh wt)

Readily available

(% of total)

N P2O5 K2O N P K

FYM

25 6.0 3.5 8.0 25 60 60

Cattle slurry 6 3.0 1.2 3.5 30-50 50 90

Sewage

sludge

25 7.5 8.7 0.8 15 50 100

Green waste

compost

66 7.3 3.0 5.5 <10 15 50

Compost use

• 1997 – 2000 study

• Green waste compost

• Animal manures (FYM, cattle slurry, poultry bedding)

• Spread at various rates, both annually and as a one off application

Effects on yields

Linseed

Wheat

Barley

OSR

Wheat

0

2

4

6

8

10

12

1996 1997 1998 1999 2000

Yie

ld

(t/

ha)

Standard fertiliser applications

Slightly reduced fertiliser applications + low rate compost

No fertiliser application + high rate compost

Much reduced fertiliser application + high rate compost

• Green waste compost used on its own or in combination with artificial fertilisers

• A series of combinable crops were grown

Green waste compost: • Is a good source of P and K

• Contains nitrogen in a very unavailable form

which is unlikely to lead to nitrate leaching

• May improve soil structural and soil biological life

• Is particularly appropriate for use in farming systems where the crops are of high value

Shredding

Turning windrow

Screening Spreading

Consider Above & Below Ground

Root Spread and depth ?

Winter wheat Spring Wheat Peas Sugar Beet Pots W clover Lucerne

Winter wheat Spring Wheat Peas Sugar Beet Pots W clover Lucerne

Consider Above & Below Ground

Green manure & cover crops

Mustard Green Manure

– ‘Nurse Crop’ Vetch

Use Green Manures & Cover crops

Establish as an undersow in previous crop?

Forage Legumes

White clover Trifolium repens

Red clover Trifolium pratense

Crimson clover Trifolium incarnatum

Subterranean clover Trifolium subteranneum

Alsike clover Trifolium hybridum

Persian clover Trifolium resupinatum

Egyptian clover Trifolium alexandrinum

Lucerne/alfalfa Medicago sativa

Winter/common vetch Vicia sativa

Summer/goar vetch Vicia lathyroides

Hairy vetch Vicia hirsuta/villosa

Kidney vetch Anthyllis spp

Sanfoin Onobrychis viciifolia

Large birdsfoot trefoil Lotus pedunculatus

Birdsfoot trefoil Lotus corniculatus

Trefoil/black medick Medicago lupulina

White lupin Lupinus alba

Yellow lupin Lupinus luteus

Blue lupin Lupinus angustifolius

Grain legumes

Field peas Pisum sativum

Fodder (grey) pea Pisum arvense

Field bean Vicia Fabia

French /pinto bean Phaseolus vulgaris

Soya bean Glycine max

Lentil Lens culinaris

Other legumes

Galega, Goats rue Galega orientalis

Chickling vetch, sweet pea Lathyrus spp.

White Sweet clover Melilotus alba

Chickpea Cicer arietinum

Black bean Castanospernum australe

0 100 200 300 400 500 600

kg N/ha/year

Red clover (silage)

Lucerne (silage)

Field bean (grain crop)

Forage peas

White clover/grass (grazed)

Lupin (grain crop)

Vetch (cut & mulched)

Soya (grain crop)

White clover/grass (silage)

Provisional ranges for quantities of N fixed and remaining after harvest

N fixed

N after harvest

(including roots)

Source : OF0316 – Adas, Abacus Organic, Duchy College, IGER

Conclusions • Soil biology is key to soil health

• Nutrients require microbial processing

• Soil microbes need good stable habitat

• Feed soil microbial populations

• Green manures, catch crops, cover crops

• Consider quick growing spp. - between

harvest and planting next crop

• Under-sow in previous cash crop

• Environmental management / X compliance

• Cultivations – catastrophic for soil biology

• Cultivations - Inversion > non-inversion

• Reduce biological disruption = reduce nutrient loss

• Use all fertilisers carefully – salts damage soil life

• Fungicides & insecticides damage soil life

• Index soil analysis – replacement of ferts only

• Consider soil biological monitoring

If you value your soil read these

“A GOOD FARMER IS“A GOOD FARMER IS NOTHING MORE NOTHING MORE NOR LESS THAN A NOR LESS THAN A

HANDYMAN WITH A HANDYMAN WITH A SENCE OF HUMUS”SENCE OF HUMUS”

(E.B WHITE)

Become subterranean livestock farmersBecome subterranean livestock farmers

Stephen Briggs MSc, BSc, IOTA, Nuffield Scholar

[email protected]

mailto:[email protected]

A practical look at soil organisms

Matthew Shepherd – Senior Specialist, Soil Biodiversity

Objectives:

• You’ll appreciate the work that soil life does, and what it needs to function

• You’ll meet some soil organisms up close and think about how they live

• You’ll explore how land management affects soil life and soil function

Policy Background – Ecosystem Services

Soil’s work for Farmers

Photo: waterboards.ca.gov

Photo: Tom Powers, University of Nebraska Lincoln

Soil’s Work

• “the biological engine of the earth”

• Engines need fuel…

Illustrations: Matthew Shepherd

What does the soil do?

• Carbon in plant organic matter is the carbon source…


Plants

• Litter

• Roots

• Root exudates

Photo: Matthew Shepherd

What does the soil do?

• So what’s the engine…

• Soil life!


Bacteria

Bacteria

Myxobacteria photo: Michiel Vos doi:10.1371/journal.pbio.0030398

Photo: Julia Plotnikov

Firmicutes Photo: Wikimedia commons

Photo: GrahamColm at en.wikipedia

Photo: http://genomics.energy.gov

http://dx.doi.org/10.1371/journal.pbio.0030398

//en.wikipedia.org/wiki/User:GrahamColm

//en.wikipedia.org/wiki/User:GrahamColm

http://en.wikipedia.org/

http://genomics.energy.gov/

http://genomics.energy.gov/

Photo: Matthew Shepherd Photo: Matthew Shepherd

Photo: MS Turmel, University of Manitoba,

Plant Science Department

Fungi (incl.

mycorrhiza)

Decomposers Photo: Kirsten Harvey

Photo: Michel Vuijlsteke Photo: Sonia Martinez

Photo: Andy Murray




Photo: B Kimmel at nl.wikipedia

Predators


Photo: Matthew Shepherd Photo: Palica, Wikipedia


Photo: James K. Lindsey

Earthworms and

Potworms

Photo: Michael Linnenbach

Photo: Natural History Museum, London

Photo: Mihai Duguleana

What does soil life need to work?

• Energy source – plant roots, litter, exudates and partnerships

• Space to live – soil pores and litter

• Moisture

• Lack of disturbance (at their level and timescale)

• Chemical stability – pH, solutes etc.

• No dangerous toxins

• Comfortable temperatures

Activity Sessions – 12 mins each

• Session 1: Assessing soil biological health – looking at soil blocks – what they can and can’t tell us.

• Session 2: Meet the soil Beasties – quick whiz around the microscopes – factsheets.

• Session 3: Problems, solutions and impacts – card game

• PLEASE LEAVE EACH ACTIVITY AS YOU FIND IT!

Thank you!

Photo: Stuart Norris

Soil structure and Field Traffic Management

Tim Chamen

CTF Europe

What is “good” soil structure?

• A soil that sustains healthy and high yielding crops as well as fulfilling its role of buffering chemicals, water and air to maintain a healthy environment

– the economics of creating and maintaining this have to work as well!

What are the physics of a “good soil structure”?

• A heterogeneus (diverse) mix of solids, air and water with a continuous network of pores that allow free movement of air, water and roots

Recognising good and bad soil structure

Good Bad

Examples of good & poor soil structure

Good

Poor in parts


Reasonably good

Very poor


Good

Poor

Examples of good & poor structure

Good

Poor

What can we influence or manage?

With acknowledgement to R.C. Palmer, Independent Soil Assessment Specialist [email protected]

The volume of soil that we can influence

How do we improve soil structure?

• Increase organic matter levels

– Maximise level and duration of green or other cover

– Avoid stresses on the soil:

• compaction

• tillage

• starving wildlife

• bare fallows – at any time

• raindrop impact

The importance of SOM!

• Without soil organic matter (SOM), soils have no structure or life

– SOM is the primary food source for all soil living animals and micro-organisms

– SOM initiates aggregation of soil particles and thus porosity

– Animals and roots create further porosity

The dynamics of SOM

• Plants add SOM

• Soil micro-organisms break it down – Addition or loss of SOM is the balance of these

two processes

• “Inappropriate” tillage increases loss by exposing more of the soil to microbes

+ -

+ -

Increasing SOM

• There is no controversy about increasing SOM

– it is beneficial on practically all levels

Addition of SOM

• High yielding crops

• Manures

• Composts

Addition of SOM

• Cover crops

–with large vigorous roots

– as much growth and over as long a time period as possible

–must be compatible with cash crops

Loss of SOM

• Vigorous tillage in poor soil conditions

Loss of SOM

• Whole crop removal

• only cover cropping has any chance of maintaining status quo

Water dynamics

Compaction stops water getting into and draining out of soils

After: Chyba, 2012

The effect of pore size on drainage

Effect of pore size on drainage

Hinge – narrow end

Water drainage

Effect of impervious layers on soil water content

• A practical demonstration of drainage constraints

Effect of poor water dynamics!

Compaction makes soils stronger

First video, random traffic no-till for 3 years

Second video, zero traffic no-till for 3 years

Compaction makes soil management more difficult and costly

• Energy to loosen. Energy to re-compact

• Loss of moisture

• Uneven germination and growth

– Timeliness effects on subsequent chemical applications

FIELD TRAFFIC MANAGEMENT

Addressing the principles Choosing and using tyres correctly

• Learn the principles

– manufacturer’s literature and training workshops

• tyre data book or pdf

– lowest inflation pressure for load and speed

Tyres – what’s the correct inflation pressure?

• Example from tyre data book

– 18.4R34 tyre

Tyre rolling radius, mm

Max speed, km/h

Load, kg at:

Pressure 0.8 bar 1.0 bar 1.2 bar

744 10 2745 3010 3275

744 30 2160 2370 2580

744 40 2015 2210 2410

Choosing the right tyres

Axiobib - 20% more load at same pressureAxiobib - 20% more load at same pressure

Xeobib – 40% more load at same pressureXeobib – 40% more load at same pressure

Tyres have very different characteristics

What can be achieved

Combine on standard tyres

What can be achieved

Same day, same combine but on low pressure tyres

Differently priced options!

Tracks

• Lay down area in length rather than width

– but pressure not even under this length

Ground pressure time history

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 1 2 3 4 5 6 7 8 9 10

Time, secs

Record

ed p

ressure

, bar

128

107

177

271

421

Run No. 4\3\1\009

combine rear wheels

combine track

Accepted thinking: most stress under tracks is

dissipated in the topsoil

Tracks

• Advantages

– Less area tracked on each pass

– More efficient pulling power

• 4% compared with 10% slip

– Less rutting

• Disadvantages

– Heavier than wheels

– More expensive than wheels

– Can do more damage to crops on turning

Good

Not so good

265 kW tracked tractor – 25% premium compared with equivalent wheeled tractor of 425 kW

Setting up machinery combinations properly

• Mounted cultivators

– correct ballasting

– 3-point hitch geometry

• top link position should ensure weight transfer onto rear wheels

• Trailed cultivators

– correct ballasting

– particularly important with single tracks

Fuel savings

• Adaptive driving 10-20%

• Appropriate settings 5-10%

• Engine maintenance 5-10%

• Diesel quality 3-5%

• Appropriate ballast 5-8%

• Correct tyre pressures 5%

Keep an eye on weight

• Take time to remove excess weight

Not always easy or appropriate

and can remove too much!

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.00

Timeline from the 1930s to the present day

Pre

dic

ted

pre

ssu

re a

t 0

.5 m

de

pth

, bar

850 kg Horse

11.2-28

12.4-36

16.9-34

18.4-38

16.9 R 34

710/70 R 38

800/65R32

1050/50R32

The effects of increasing weight

2.5 t vehicle

21 t vehicle It’s load that does damage at depth

And we apply weight to a big area

Traditional: Average: 85% tracked

Kroulik et al,

2011

grain carting

straw carting

straw baling

Wheat Czech Republic

• any system that confines all tracks to least possible area of permanent traffic lanes

– CT is NOT prescriptive about tillage

– CT is NOT just about keeping tramlines in the same place

– Commitment to continual improvement

Another approach

Controlled Traffic Farming - CTF

CTF can turn tracking on its head!

CTF: 85% not tracked

CTF has a lot of benefits

• Yield improvements

• Improved fertilizer use efficiency

• Lower and less intensive tillage

• Large fuel savings

• Lower operating and capital costs

• Improved soil health

– 4 x better water infiltration & conductivity

– lower greenhouse gas emissions

– more soil-living animals

but equally CTF has some drawbacks

• It needs careful planning and attention to detail

– matching track gauges

– matching implement widths

• It requires investment in auto-steer

• It introduces an element of inflexibility

• Probably needs a change in agronomy

– less and shallower tillage

– different soil structure

Trailer

Grain auger

Cereal harvesting

Cultivator/drill

Chemical application

Take home messages

• Improving soil structure is a long-term commitment involving

– lowering soil stresses

• tillage and traffic

• choosing and using tyres correctly

– increasing organic matter levels

• less tillage

• cover cropping

• retaining residues

• adding composts and manures

Take home messages

• Improving soil structure

– Controlling traffic can be part of the solution

– It can also:

• make farming simpler

• lower inputs

• raise yields

• reduce negative environmental impacts

Join the Smart Agri-Systems Platform for information on soils and precision farming

Stephen Briggs

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