ANEESH, S

PRESENTATION TOPICS

• Biological nitrogen fixation and bio-fertilizers.

• Farm yard manure and other organic fertilizers.

• Mycorrhizal associations and their significance.

• Economic implications of nutrient management.

• Importance of renewable waste and their recycling.

MYCORRHIZAL ASSOCIATIONS

AND THEIR SIGNIFICANCE.

OVERVIEW

• Mycorrhiza -introduction

• Major benefits the seedlings derive from mycorrhizae

• Environmental factors and management practices that affect• Environmental factors and management practices that affect

mycorrhizal fungus populations and their subsequent

development

• Methods to foster mycorrhiza development in bareroot nurseries.

• Methods for artificially inoculating seedlings with selected,

highly beneficial mycorrhizal fungi.

MYCORRHIZA

• Term mycorrhiza was coined by Frank

• Mycorrhiza is a Greek word meaning ‘fungus-root’

• Mycorrhiza involves the intimate association of plant roots with

specialised soil fungi.

• Mutualistic symbioses

• Considered as an extension root system

• Fine network of fungus threads (hyphae) explores and extractsnutrients from a volume of soil far beyond the bounds of the roots'capabilities.

• Many of these nutrients are translocated through the hyphal

network to the mycorrhizae, where they are released to the

roots for host utilization.

• In exchange, the host serves as primary energy source for the

fungus, providing simple sugars and possibly other

compounds derived from host photosynthates

.

ECTOMYCORRHIZAE

• The fungi colonize the surfaces of the short feeder roots, often

forming a thick mantle around them.

• Ectomycorrhizae can be seen with the unaided eye or a hand lens

because many are white or brightly colored.

•A dense mold like fungal growth is visible in the soil when seedlings

are lifted if ectomycorrhizae are abundant

• Fungus enter the root, penetrating between the cortical cells to form

an interconnecting network called the Hartig net.

• It is within this extensive hypha-root cell contact zone that nutrient

exchange occurs.

• The fungi produce plant hormones that stimulate root

branching and elongation, thereby increasing the root's

absorptive surface.

• Branching patterns of ectomycorrhizae are often host

determined and are therefore characteristic of the host-determined and are therefore characteristic of the host-

seedling species.

ECTENDOMYCORRHIZAE

• A subtype of ectomycorrhizae

• Ectendomycorrhizae branch like ectomycorrhizae but lack

root hairs

• It forms Hartig net

• The fungi also penetrate scattered cortical cells

VESICULAR-ARBUSCULAR MYCORRHIZAE

• Vesicular-arbuscular mycorrhizae cannot differentiate morphologically

from nonmycorrhizal roots

• Roots must be selectively stained to highlight the fungus within and

then examined microscopically to determine its presence and structure.

• They form the characteristic vesicles and arbuscules for which the• They form the characteristic vesicles and arbuscules for which the

mycorrhiza is named.

• Vesicles are storage organs containing carbohydrates and also serve as

reproductive structures.

• Arbuscules are very finely branched, short-lived, intracellular structures

which partake in nutrient exchange.

• The main portion of the VA fungus lies outside the root,exploring the surrounding soil for nutrients and translocatingthem to the roots.

• Unlike ectomycorrhizal fungi, VA fungi do not produce largemushroom-like reproductive structures.

• Instead, they produce large, mostly soil-borne, globose spores.

• VA fungus spores cannot be dispersed for long distances by airmovement

• Spore dispersal is limited primarily to mechanical movement ofsoil.

• This has high relevance in the management of VAM fungi

BENEFITS OF MYCORRHIZAE

• Enhanced uptake of nutrients, especially Phosphorus

• They take up water and increase drought resistance of young seedlings

• Some mycorrhizal fungi can also detoxify certain soil toxins

• It enable seedlings to withstand high soil temperatures or extreme acidity

• Some mycorrhizal fungi can protect roots against certain pathogens

Eg: mycorrhizal fungus Laccaria laccata. has been shown to protect feeder

roots from Fusarium infection

FACTORS INFLUENCING MYCORRHIZA

• Mycorrhiza development in nurseries is affected by several

biologic and environmental factors

• Nurseries established in forest zones or surrounded by

ectomycorrhizal hosts usually produce seedlings with abundant

and diverse ectomycorrhizae.and diverse ectomycorrhizae.

• Nurseries developed away from native forests or on new ground

with no history of ectomycorrhizal hosts can experience

mycorrhiza deficiency, resulting in serious financial and

reforestation setbacks.

• Such seedlings are stunted, chlorotic, and severely nutrient

deficient

• Soil fumigation - fumigation with methyl bromide/chloropicrin

gases usually eliminates mycorrhizal fungus populations along

with targeted pests.

• Fumigation can cause a lengthy delay in mycorrhiza development,

resulting in substantial growth loss the first growing season.

• Soil fumigation is particularly devastating to VA mycorrhizal• Soil fumigation is particularly devastating to VA mycorrhizal

Fungi

• Because VA fungus spores are not dispersed by air, once the

population is eliminated, such spores are returned to fumigated

beds only movement of spore-containing soil by machines and on

shoes.

• Different tree species vary in susceptibility to mycorrhiza

deficiency.

• Douglas-fir and true firs appear especially mycorrhiza dependent

and show symptoms of mycorrhiza deficiency more quickly thanand show symptoms of mycorrhiza deficiency more quickly than

pines.

Nursery soil system

• Nursery soils that are good for tree seedling growth are also good

for mycorrhiza development on those seedlings.

• Good organic matter content, good tilth, good drainage, and

adequate but not excessive nutrient levels are all associated with

good mycorrhiza formation .good mycorrhiza formation .

• Effects of fertilization on mycorrhiza formation- they become

suppessed with addition of high concentrations of inorganic

fertilizer

Selective biocides can be used instead of or in conjunction with

soil fumigation.

Herbicides do not generally appear to depress mycorrhiza

formation and in some cases even seem to increase it, possibly by

increasing exudation of sugars from roots

Weed control thus seems compatible with mycorrhizaWeed control thus seems compatible with mycorrhiza

Management

Insecticides and nematicides at field-application levels generally

appear not to harm mycorrhizae or depress mycorrhiza formation.

Some fungicides, on the other hand, are inhibitory

• Crop rotation : Switching rotations from ectomycorrhizal to VA mycorrhizal

trees can produce mycorrhiza deficiency because the fungi of the two

mycorrhizal types are totally different.

• Because spores of VA mycorrhizal fungi do not disperse by air,

recolonization of beds can be slow and the tree crop accordingly poor.recolonization of beds can be slow and the tree crop accordingly poor.

Seedling manipulations

• Procedures such as wrenching, undercutting, and mowing are not

known to inhibit mycorrhiza formation, but they cost seedling energy.

• Practices such as wrenching break up much of the nutrient-absorbing

network of fragile hyphae that grow from the mycorrhizae into

surrounding soil.

• These hyphae will regrow but at the cost of seedling-produced energy• These hyphae will regrow but at the cost of seedling-produced energy

that would otherwise have been available to increase seedling size.

• Procedures such as lifting, sorting, packing, storing, and transporting

seedlings should be performed with care to minimize damage to the

fine-root system.

• Mycorrhizae destroyed by rough handling, desiccation, or heating will

have to be replaced at the planting site at a cost of seedling energy and

nutrients.

MYCORRHIZAL INOCULATIONS IN

BAREROOT NURSERIES

• To eliminate potential or current mycorrhiza deficiencies or

• To improve outplanting performance of seedlings.

• Several procedures are available for introducing mycorrhizal

fungi.

1. Ectomycorrhizal inoculation

2. VAM Inoculation

ECTOMYCORRHIZAL INOCULATION

Four primary sources of ectomycorrhizal inoculum are

available

1. Soil inoculum,

2. Use of nurse seedlings2. Use of nurse seedlings

3. Spores and sporocarps

4. Pure fungus cultures

• Each has advantages and disadvantages

• Nursery managers should carefully weigh each option before

selecting which approach best suits their needs.

SOIL INOCULUM

The most commonly used and the most reliable method of inoculation

• Forest soil taken from beneath ectomycorrhizal hosts.

• About 10% by volume of soil inoculum is incorporated into approximately

the top 10 cm of nursery-bed soil before sowing or transplanting

• Inoculation of new or fumigated beds by soil taken from established beds

is also feasible.

Drawback

• Collection and transportion the large quantities of soil needed for

inoculation

• Weed seeds, rhizomes, and potential pathogens maybe introduced along

with the beneficial fungi

"NURSE" SEEDLINGS

• Planting mycorrhizal "nurse" seedlings from which the funguscan spread and colonize new seedlings

• Chopped roots of ectomycorrhizal hosts into nursery beds canalso provide a source of ectomycorrhizal fungus inoculum.

Disadvantage

• Mycorrhizal colonization may spread slowly and unevenly

• The large "nurse" seedlings can interfere with culturalpractices

• The risk of introducing unwanted pests

SPORES AND SPOROCARPS

• Spores and chopped sporocarps (mushrooms, puffballs, and

truffles) of some ectomycorrhizal fungi provide an excellent

source of natural inoculum.

• Large quantities of spores can be easily collected• Large quantities of spores can be easily collected

• Variety of application methods are available including

dusting, spraying, coating seeds, and applying in a

hydromulch,

PURE FUNGUS CULTURES

• Pure cultures of specially selected, beneficial

ectomycorrhizal fungi

• A pure culture of a specific fungus is first isolated, usually

from a sporocarp or, occasionally, directly from itsfrom a sporocarp or, occasionally, directly from its

ectomycorrhiza

Selection criteria

• Good growth in culture: relatively fast-growing isolatesare preferred.

• Effectiveness in forming mycorrhizae

• Special ecological adaptations• Special ecological adaptations

• Competitive ability

• Host range

• Improved seedling performance in plantations

VAM INOCULATION

• VAmycorrhizal fungi have not yet been isolated and grown

in pure culture

• They must be attached symbiotically to their hosts to growand reproduce.

• This presents a major obstacle to aseptic mass production ofVAmycorrhizal fungi for large -scale nursery inoculations.

1. Soil and root inoculum

2. Pot-cultured inoculum

SOIL AND ROOT INOCULUM

• Incorporate soil (plus root fragments) taken from under VA

mycorrhizal hosts.

• VA mycorrhizal fungi show little or no host specificity - VAMassociated with grasses, legumes, and several herbs and shrubs can form

VAmycorrhizae with cedars, redwoods, sweetgums, and maples.VAmycorrhizae with cedars, redwoods, sweetgums, and maples.

• Locating soil with VAmycorrhizal fungi is relatively easy.

Drawback

• The risk of introduction of pests

• Need to move large quantities of soil can be impractical.

POT CULTURE INOCULUM

• Refined techniques to multiply and introduce selected VAM fungi

through pot culturing

• Soil-borne spores of VAM are collected

• Spores are then surface sterilized and mixed with sterilized soil

• A host plant is grown in this inoculated soil

• As host roots penetrate the inoculated substrate

• Spores germinate and colonize the roots to form mycorrhizae

• After about 4 to 6 months, the fungus will established its hyphae-soil

network and will produce more spores.

• Once such pot cultures are established, the soil containing spores,

mycelium, and colonized root fragments can be used to inoculate nursery

or field crops.

Pot culturing also affords the opportunity to select species, strains, ormixtures and thus offer the greatest benefit to the targeted host species.

Application of VA inoculum

• VA fungus inoculum can be broadcast into seedbeds

- large amounts of inoculum are needed to obtain rapid root colonization.

• Inoculum can be banded or side dressed next to seeds or seedlings

- Effective when inoculum quantities are limited

- For best results, bands should be placed in an area of root proliferation,- For best results, bands should be placed in an area of root proliferation,usually about 5 to 15 cm from seedlings or seeds.

- Placing inoculum in layers or pads directly beneath seeds wheredeveloping roots will penetrate the inoculum is the most effective.

• Layering of inoculum has been successful for peach and citrus .

• Inoculum can be applied with commercial tractor-drawn seeders orfertilizer banders

• Seed has been pelleted with VA fungus inoculum

FERTILIZATION IN FOREST NURSERY

• Fertilization of nursery soils is necessary to replacelost nutrients

• Fertilizers can be organic (such as compost ormanure) or inorganicmanure) or inorganic

• The concentrations of nutrient elements in organicfertilizers are usually low

• Inorganic fertilizers, contain high nutrientconcentrations.

ORGANIC FERTILISERS

• Compared to agricultural crops, organic matter (OM) is depletedmuch more rapidly in forest seedling nurseries as the entire plantis removed at the end of the growing cycle.

• OM have favorable influences on soil chemical and physicalproperties.properties.

• Incorporation of OM, can increase pore space and counteract thenegative impacts of compaction.

• Organic fertilizers act as a slow-release fertilizer

• Provide plants with essential macro- and micro-nutrients.

• Incorporation of slow release fertilisers into the

nursery medium significantly improve the

growth trees in the plantation.

• This will optimise nutrient placement and

minimise nutrient-loss beyond the root zone of

establishing trees.

GREEN MANURE CROPS

• Green manure crops are important in bare root nursery

• Enrich organic matter content of soils.

• Legumes - supply both OM and fix N

• Protect the soil from erosion• Protect the soil from erosion

• Green manure crop can be incorporated into the soil at

optimum C:N ratio

• Important green manure crop : Crotolaria juncea, Sesbanea

aculeata, Indigifera tinctoria

• Non legume – Cannabis sativa

COMPOST

• Compost produced from weed and coir pith used for root trainer seedling

production.

COMPOST PRODUCTION BY AEROBIC PROCESS USING WEED

• Weeds are harvested during June - September • Weeds are harvested during June - September

• Harvested weeds are chopped into 1-1.5cm pieces

• Keep it for 1 or two days to reduce MC

• Spray with water and mix thoroughly by turning over

• Chopped weeds are arranged into heaps of ( 2m width x 1.25m) height in shed

with overhead protection from sun and rain

• Urea amendment is sprinkled uniformly in between 15cm thick

layers of weed during initial heaping. (1kg Urea per Tone of fresh

weed )

• Spray optimum quantity of water in each layer

Comopst processing

• Within 2 to 3 days temperature inside the heap will rise

• When temperature exceed 60 0c the compost heap should be turned

over (once in a day or two)over (once in a day or two)

• Sprinkle the water while turning

• The number of turning required is 20 or more depending on plant sp

used and season of composting

• Curing for one month and air drying under shade for one day

• Sieving (16 -25 mesh per 2.5cm x2.5cm size )

• Store it in gunny bags

BIOFERTILISERS

• Biofertilizers are fertilizers containing living microorganisms,

which increase microbial activity in the soil.

• Biofertilizers encompass the formulation of nitrogen fixing

microorganisms, phosphate solubilizing microorganisms and

cellulolytic microorganisms.cellulolytic microorganisms.

• Enviornment friendly

• Low cost

• Non bulky

RENEWABLE WASTE AND THEIR RECYCLING

• Rapid urbanization, industrialization, and changes in the pattern of

civic life have resulted in the generation of enormous quantities of

wastes in the urban and industrial areas of the country.

• Urban population increasing between 3 – 3.5% per annum

• Per capita waste generation in India is 5 kg per day

• Yearly increase in waste generation is around 5% annually

• Each year, about 30 million tonnes of municipal solid waste

(MSW) are generated in India

CHARACTERISTICS OF MUNICIPAL SOLID WASTE

• Compostable / Bio-degradable = 30% - 55%

matter

(can be converted into manure)

• Inert material = 40% - 45%

( go to landfill )( go to landfill )

• Recyclable materials = 5% - 10% (Recycling)

• These percentages vary from city to city depending onfood habits

PRESENT STATUS OF WASTE

MANAGEMENT

• Storage of waste at source is lacking

• Domestic waste thrown on streets

• Construction debris left unattended

• Bio-medical waste disposed in municipal waste stream

• Industrial waste disposed of in open areas

• Segregation of recyclable waste at source not done

• Primary collection of waste not done at place of

generation

RECOMMENDED APPROACHES TO WASTE

PROCESSING & DISPOSAL

• WASTE TO COMPOST

(i) AEROBIC / ANAEROBIC COMPOSTING

(ii) VERMI-COMPOSTING

• Seedling could not establish when fresh garbage is used

• Favorable effect on germination and growth in Dalbergia

latifolia when 4 weeks decomposed municipal waste is used

as potting media (Sreelekha, 2004).

References• Dureya, L.M and Landis, D.T. 1984. Forest Nursery Manual. Dr. W. Junk

Publishers, Netherlands. 211- 223 pp.

• Dwivedi, A.P.2004. Text book of silviculture. International book

distributors, Dehradun . 82 -88 pp.

• Sreelekha, P.T. 2004. Effect of municipal garbage on the growth and vigour• Sreelekha, P.T. 2004. Effect of municipal garbage on the growth and vigour

of Rosewood(Dalbergia latifolia) seedling in nursery. MSc Thesis. College

of Forestry, Kerala Agricultural university.