Green manuring is the plowing under or soil incorporation of any green manure crops while they are green or soon after they flower. Green manures are forage or leguminous crops that are grown for their leafy materials needed for soil conservation.

Advantages of green manuring

1.     Improves the soil fertility

2.     Add nutrients and organic matters

3.     Improves the soil structure

4.     Improves soil aeration

5.     Helps control insect/mite pests, nematodes, and diseases

6.     Helps control weeds

7.     Promotes habitat for natural enemies

8.     Increases soil’s biodiversity by stimulating the growth of beneficial microbes and other soil organisms

Green manure crops

Green manure crops	Seeding rate  (kg/ha)	Green biomass (t/ha)	Dry biomass  (t/ha)	Nitrogen content  (%)	Nitrogen (kg/ha)	When to  incorporate  in the soil? (DAP)
Azolla	50-90	8-10	1.8-3		52	35
Cowpea	40	9-10	3-4	1.4-1.5	140-150	40-60
Lablab	7-18		5-7		220	45-60
Mustard	5-12			3.5		21-37
Pigeon pea	45-67	9-10	5-7			45-60
Sesbania	20-90		1.5-4	4.3	250-360	45-50
Soybean	30-56		5-7.4		310	45-60
Sun hemp	35-40	5-19	5.5-6	1.7	108	50-60
Sweet clover	30-40	12	6	2		40-50

Criteria for the selection of green manure crops

1.      Fast growing

2.      Produce abundant and succulent tops

3.      Well adapted to the local condition

4.      Can fix nitrogen in the soil

Reminders

1.     Broadcast or sow the seeds after harvest

2.     Cut the greens after flowering and plow them under

3.     Sow or transplant the next crops 1-2 weeks after the incorporation of the green manure