Green Manure

Green Manure

Green undecomposed material used as manure is called green manure. It is obtained in two ways: by growing green manure crops or by collecting green leaf (along with twigs) from plants grown in wastelands, field bunds and forest. Green manuring is growing in the field plants usually belonging to leguminous family and incorporating into the soil after sufficient growth. The plants that are grown for green manure known as green manure crops. The most important green manure crops are sunnhemp, dhaincha, pillipesara,clusterbeans and Sesbania rostrata.

Biomass production and N accumulation of green manure crops

Crop	Age (Days)	Dry matter (t/ha)	N accumulated
*Sesbania aculeata*	60	23.2	133
Sunnhemp	60	30.6	134
Cow pea	60	23.2	74
*Pillipesara*	60	25.0	102
Cluster bean	50	3.2	91
*Sesbania rostrata*	50	5.0	96

Nutrient content of green manure crops

Plant	Scientific name	Nutrient content (%) on air dry basis
Plant	Scientific name	N	P2O5	K
Sunhemp	*Crotalaria juncea*	2.30	0.50	1.80
Dhaincha	*Sesbania aculeata*	3.50	0.60	1.20
Sesbania	*Sesbania speciosa*	2.71	0.53	2.21

Sesbania rostrata is a stem nodulating green manure crop which is a native of West Africa. As it is a short-day plant and sensitive to photoperiod, the length of vegetative period is short when sown in August or September. A mutant (TSR-l) developed by Bhabha Atomic Research Centre, Bombay is insensitive to photoperiod, tolerant to salinity and waterlogged condition. Growth and nitrogen fixation is higher with TSR-l compared to the existing strains.

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