Dr. P. K. ManiBidhan Chandra Krishi Viswavidyalaya

E-mail: pabitramani@gmail.com Website: www.bckv.edu.in

Green manuresGreen manures

Green manure refers to “a plant material Green manure refers to “a plant material incorporated with the soil while incorporated with the soil while greengreen or or soon after maturitysoon after maturity for improving the soil for improving the soil to supply nutrients, particularly N, to a to supply nutrients, particularly N, to a standing crop”standing crop”

(Soil Science Society of America, 1978)

Green manuresGreen manures

Green manuring is a practice of ploughing or burying the undecomposed green plant tissues into the soil for improving structure and fertility of the soil.

Green-manuring can be done in 2 ways depending on the situation. (i) Green-manuring in situ: this is the growing and burying of a green manure crop in the same field as the one to be manured.

(2) Green-leaf manuring: GLM refers to turning into the soil green leaves and twigs collected from shrubs and trees grown on bundhs, wastelands or nearby forest areas

Sesbania rostrata

Crops suitable for green leaf manuring

Legumes: Glyricida ( Glyricidia maculata),

Wild dhaincha (Sesbania speciosa),

Karanja (Pongamia pinnata),

Wild indigo (Tephrosia purpurea,

Glyricidia Pongamia Leucaena leucenalis

Characteristics of green manure crops

Profuse leaves and rapid growth in early life

Abundance and succulent tops

Capable of making good stand on poor and exhausted soils

Preferable legume with good nodular growth habit

Advantages of Green ManuringAdvantages of Green Manuring

It add organic matter to the soil and stimulates microbial activity

Improves soil structure

Acts as a cover crop ,facilitates penetration of rain water, decreasing erosion and run off

Nutrient taken up from the deeper layers by green manure crops and return the nutrient to the

top soil

Legume crop also add nitrogen

Rainfed condition : Green manure crops will not decompose readily due to lack of water

GM is feasible for assured irrigation facility

Cost of growing GM crop is more than cost of Fertilizer

For higher Cropping intensity land is unavailable for GM cultivation

Disease, insects and nematodes may come up due to improper decomposition

LimitationsLimitations

Methods of Green Manuring in situSummer sown catch crop

Land Preparation: 3-4 ploughings followed by 1 laddering

Sowing : May-June , immediately after 1st monsoon rains. Dhaincha and Sunhemp are generally sown in Aman Paddy field for green manuring.

Method of sowing: broadcasting

Seed Rate: Dhaincha : 40-45 kg/ha Sunhemp : 40-50 kg/ha Moong : 25-30 kg/ha

Manuring: Superphosphate@150 kg/ha applied at last ploughing(increases the P availability for succeeding Aman rice

Burial of GM crops: at the flowering stage; (Dhaincha 6-8 wks old, Sunhemp: 4-5 wks old). During decomposition there must be adequate moisture in the field and allowed to decompose for 3-4 weeks

DHAINCHA (Sesbania aculeata)

Sesbania Seed

Cultivation of Chaiti Moong at AB Farm, BCKV

green manure -cum-fibre crop SUNNHEMP (Crotalaria juncea)

Sunhemp SeedSunn Hemp provides as much as 20 tons per acre of green tonnage with a maximum of 150 units of Nitrogen fixation per acre in as little as 90 days.

Inter row sown crop:

The seed sown between two rows; Dhaincha (paddy)

Sunhemp, cowpea (Cotton , Maize)

Green Leaf Manuring: The suitable perennial shrubs and trees are grown on border of paddy fields or bounds or on vacant spaces for the purpose of utilizing their leaves and twigs as green manure. These are incorporated in the soil at the time of puddling of paddy field

Brown Manuring

Brown manuring is a technique to grow Sesbania in standing rice crop and kill them with the help of herbicide for manuring. After killing the color of the sesbania  residue become brown so it called brown manuring.

Brown manuring practice introduced where Sesbania crop @ 20 kg/ha is broadcasted three days after rice sowing and allowed to grow for 30 days and was dried by spraying 2,4-D ethyle easter which supplied upto 35 kg/ha N, dry matter, control of broad leaf weeds, higher yield by 4-5 q/ha due to addition of organic matter in low fertile soils

Crops suitable for green leaf manuring

Glyricida ( Glyricidia maculata),

Neem (Azadiracta indica)

Karanja (Pongamia glabra)

Wild indigo (Tephrosia purpurea)

Subabool Leucaena leucenalis2424

GlyricidiaKaranja (Pongamia glabra)

Glyricidia maculata

Root knot nematode Rhizobium nodule

High C:N ratio material added to soil

Available soil N is immobilized

C02 evolution increases

Available N increases

through N mineralization

Time

Nitrogen availability

Nitrogen immobilization and mineralization after material with a high C:N ratio is added to soil.

Mineralization, immobilization, and C:N ratio

Nitrate depression period

Residues with low C/N ratio remain

General purpose decay organisms vs. nitrifiers

Residues with high C/N ratio added

The C/N ratio of organic residues added to soil will depend upon the maturity of the plants turned under. The older the plants, the wider will be the C/N ratio and the longer will be period of nitrate suppression. Obviously, leguminous tissue will have a distinct advantage over nonlegumes since the former will promote a more rapid organic turnover in soils

Sesbania rostrata - a stem nodulating green manure

Azorhizobium caulinodans

Sesbania

on

Phosphocompost

Principles of phospho-composting

Phospho-composting is based on sound scientific principles. During the decomposition of organic materials, intense microbial activity occurs. As a result a large number of organic acids and humic substances are produced.

Some of the most commonly produced organic acids are: citric, malic, fumaric, succinic, pyruvic, tartaric, oxaloacetic, 2-ketogluconic, lacticoxalic, propionic and butyric (Stevenson, 1967).

Phospho-compost is a compost prepared by addition of low grade rock phosphate and phosphate

solubilizing micro-organisms with organic wastes.

Rock phosphate, as a cheaper source of P

In the process of decomposition many organic acids are liberated.

Due to this acidic condition, P from rock phosphate gets solubilized and compost becomes enriched.

PHOSPHOCOMPOSTIngredients:

Oragnic wastes : 80 kg (60 kg dry+20 kg green)

Raw Cow dung : 10 kg

Compost : 5 kg

Soil : 5 kg

Total : 100 kg

Rockphosphate : 20 kg

Pyrite : 10 kg

Urea : 2.2 kg

Cultures : 0.05 kgDry organic wastes: Straw, husk, waste from cattle shed, stems of mustard , sesame, etc.Green : Waterhyacinth, legumes, weeds, vegetable clippngs, leaves, grasses

Nitrogen Nitrogen required for Stimulating the microbial activity required for Stimulating the microbial activity

Pyrites are added due to acidification of the mixture during composting to prevent volatilization loss of N and also to increase P solubilization

Cellulose decomposer: Aspergillus awamori (fungi) (500g mycelial mat / ton of materials)

P-solubilizers: Bacillus megatherium.

Bacillus polymyxa,

Pseudomonas striata

(50 ml/kg of materials having 108 viable cell)

Phosphate Rocks

Divide entire Organic and inorganic component in 10 equal parts

9-12//

I part cowdung (1 kg) + compost (0.5 kg) + Soil (0.5kg) make slurry in water

Dry organic wastes

Urea (200g) + microbial Cultures(5g) make it a slurry

I part Phosphate Rock(2kg) and I part Pyrite(1kg)

Preparation of 1st Layer

1st Layer

2nd Layer 3rd Layer

4th Layer

Layer of mud with soil + cowdungCovered with Polythene sheet

Keep it for 3 months , yielding 65-70 kg PhosphoCompost

Method of Phosphocompost Making•Select a suitable upland place, sufficient sunlight, free from water stagnation•Prepare a base with either brick floor or spread the polythene sheet on the floor•Collect all the ingredients (organic and inorganic) as per proper ratio for the

desired pdn level.•Divide the entire ingredients into 10 parts•Step-1:Take one bucket and add Raw Cow dung- 1kg, Compost- 0.5 kg, Soil -0. 5 kg and small water, stir the material and make a slurry.

•Step-2: Take 2nd bucket and add urea-200g, cultures-5g and add water small, make another slurry

•Step-3:Spread dry wastes followed by green wastes and make it 12″ height•Step-4:Now add slurry from 1st bucket (cow dung etc slurry), next add slurry

from 2nd bucket and spread evenly.•Step-5: Now spread 2 kg Rock phosphate and1 kg Pyrite•Repeat the process Step-1 to step 5 and repeat until 10 layers is formed.• covered the top and side portion of the heap with Layer of mud (soil+ cowdung) and subsequently cover with poly thene sheet to prevent water

•1st turnings after 4 weeks and 2nd turnings after 8 weeks• Water is added to the heap so that moisture remains between 60 to 70%.•Add water at each turning to maintain the moisture content between 60 and 70%.•The compost becomes ready for field application within 90-100 days period.

Nutrient composition of phosphocompost

ManureTotal N

(%)Total P

(%)S C: N

ratio

Phosphocompost 1.2-1.4 2.00-3.50 1.5-2.0 17.0-18.0

Phospho-compost application increased the PUE of greengram (12.90%) and wheat (20.48%) over SSP

(Mishra et al. 1982).

WILD INDIGO (Tephrosia purpurea)

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