🌿 Green Manures and Oil Cakes

Green manures and oilcakes are key organic nutrient sources that improve soil fertility, biological activity, and nutrient availability in sustainable crop production.

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Green manures-Oilcakes-Sewage sludge-Biogas plant slurry-Plant and animal

refuges

G REEN MANURES

Green manure:

Growing the plants in-situ and incorporation in the field.

Green leaf manure

Addition of green or plant tissues obtained from elsewhere viz., trees, herbs, shrubs

pruning andunwanted weeds.

Benefit of Green manure or Green leaf manures

a. Addition of organic matter.

b. Adds Nutrient – Macro, Secondary and micro nutrients.

c. It improves physical condition of soil.

d. Act as a soil amendment to reclamation of problem soils.

e. It act as a cover or catch crop to prevent soil erosion, conserve moisture, prevent

nutrient leaching.

f. Leguminous crops fix the atmospheric – N by the roots and improves N status of the

soil.

Characteristics of Green manure

1. It should have rapid growth and shorter duration so that can be fitted in a crop rotation

2. It should yield abundant biomass and should be succulent to have rapid

decomposition

3. It should have the ability to grow on poor soils.

Nutrient content of agricultural wastes

Agricultural wastes	N	P2O5	K2O
Sugarcane Begasse	0.25	0.12	0.20
Sugarcane Begasse compost	1.40	0.45	0.60
Sugarcane Begasse Press mud	1 – 1.5	2.0	-

Press mud – compost	1.5	1.5	-
Saw dust	Traces	0.2 - 0.25
Tobacco waste	0.5 – 1.0	0.8	1.0
Tobacco seed cake	4 – 4.5	7 – 15	5 – 5.5
Tea waste	2.8 – 3.6	03. – 0.4	1 – 2
Cotton dust	1 – 1.5	-	-
Textile waste	1 – 1.5	-	-

Nutrient content of Commonly used Concentrated manures

Oil cake	N	P2O5	K2O
Groundnut cake (Decordicated)	7.8	1.5 – 1.9	1.4
Lin seed cake	5.5	1.4	1.2
Mustard cake	4.5	1.5	1.0
Neem cake	5.2	1.0	1.4
Niger cake	4.8	1.8	1.0
Pungam cake	2.5	1.0	1.0
Safflower (decordicated)	7.8	2.2	2.0
Sesamum	6.2	2.0	1.2
Castor	5.8	1.8	1.0
Coconut	3.2	1.8	1.7

Slaughter House wastes

Wastes	N	P2O5	K2O
Blood meal	10 – 12	1.2	1.0
Meat meal	10.5	2.5	0.5
Fish meal	4 -10	3 – 9	0.3 – 1.5
Horn – Hoff meal	13	-	-

Leather - waste	7	0.1	0.2
Hair and wool waste	12.3	0.1	0.3
Sewage water	25ppm	5 ppm	15 ppm
Sludge	1.5 – 3.5	0.75 – 4	0.3 – 0.6

Nutrients content of Commonly used Green manures

Green manure	N %	P2O5%	K2O %
Sunhemp	0.5	0.1	0.4
Danicha	1.1	0.2	0.4
Sesbania	0.7	0.1	0.6
Pelli pesera	0.7	0.2	0.4
Cluster bean	0.3	0.1	0.3
Cow pea	0.7	0.2	0.6
Green leaf manure	Green leaf manure	Green leaf manure	Green leaf manure
Kolungi	0.7	0.1	0.4
Calotropis	0.3	0.1	0.6
Pungam	1.2	0.2	0.8
Glyricidia	0.8	0.1	0.7
Puvarasu	0.8	0.2	0.9

Guano - Birds Excreta or bat Dung

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Summary Cheat Sheet

Topic	Key exam point
Green manure meaning	Crop grown and incorporated in situ to improve soil fertility and organic matter
Common green manure crops	Dhaincha and sunhemp are standard examples
Green leaf manure	Leaves and twigs from external sources added to fields instead of growing the crop in place
Main benefit	Adds organic matter and biologically fixed nitrogen, especially from leguminous crops
Oilcake meaning	Residue left after oil extraction from seeds
Oilcake examples	Neem, castor, groundnut and similar cakes
Oilcake use	Concentrated organic manure and sometimes pesticidal/soil-health input
Other organic sources	Sewage sludge, biogas slurry, slaughterhouse waste, guano
Exam contrast	Green manure is fresh biomass incorporation; oilcakes are processed concentrated manures
Trap	Do not mix up green manure crops with green leaf manure materials

References

3 sources • [1] [2] [3]

[1]

Indian Council of Agricultural Research (ICAR)

Official

[2]

Principles of Soil Science and Agricultural Chemistry — Standard BSc Agriculture Textbook

Book

[3]

Department of Agriculture & Farmers Welfare

Website