Green Manure

Green Manure Green Leaf Manure

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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
		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.

Advantages

1. Improves soil structure
2. Increases water holding capacity and
3. Decreases soil loss by erosion

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GREEN LEAF MANURE

Application of green leaves and twigs of trees, shrubs and herbs collected from elsewhere is known as green leaf manuring. Forest tree leaves are the main sources for green leaf manure. Plants growing in wastelands, field bunds etc., are another source of green leaf manure. The important plant species useful for green leaf manure are neem, mahua, wild indigo, Glyricidia, Karanji (Pongamia glabra) calotropis, avise(Sesbania grandiflora), subabul and other shrubs.

Nutrient content of green leaf manure

Plant	Scientific name	Nutrient content (%) on air dry basis
		N	P2O5	K
Gliricidia	Gliricidia sepium	2.76	0.28	4.60
Pongania	Pongamia glabra	3.31	0.44	2.39
Neem	Azadirachta indica	2.83	0.28	0.35
Gulmohur	Delonix regia	2.76	0.46	0.50
Peltophorum	Peltophorum ferrugenum	2.63	0.37	0.50
Weeds
Parthenium	Parthenium hysterophorus	2.68	0.68	1.45
Water hyacinth	Eichhornia crassipes	3.01	0.90	0.15
Trianthema	Trianthema portulacastrum	2.64	0.43	1.30
Ipomoea	Ipomoea	2.01	0.33	0.40
Calotrophis	Calotropis gigantea	2.06	0.54	0.31
Cassia	Cassia fistula	1.60	0.24	1.20

Advantages

1. Green manuring improves soil structure, increases water holding capacity and decreases soil loss by erosion.
2. Growing of green manure crops in the off season reduces weed proliferation and weed growth.
3. Green manuring helps in reclamation of alkaline soils. Root knot nematodes can be controlled by green manuring.