Biofertilizers and Green Manure

Biofertilizers (a type of organic fertilizers)

Substance which contains living microorganisms ex. Azobacter, Rhizobium, Bacillus, Nostac, Anabaena. When applied to seed, plant surfaces, or soil, it promotes growth by increasing the supply or availability of primary nutrients (nitrogen, Phosphorous etc.) to the host plant

Pros

Increases crop yield by 20-30% & also provide protection against drought and some soil-borne diseases
Replaces chemical nitrogen & phosphorus by 25%, and stimulates plant growth
Cost-effective, Environment friendly & also helps to some extent, to cleanse the plant from precipitated chemical fertilizers

Cons

Effects are slower compared to chemical fertilizer
Difficulty to store as sensitive to temp. and humidity changes
Much lower nutrient density — requires large amounts to get enough for most crops
Sometimes, are hard to locate/purchase in faraway rural areas

Green Manure

a type of cover crop grown primarily to add nutrients and organic matter to the soil.
a green manure crop is grown for a specific period of time, and then ploughed under and incorporated into the soil while it is still green or shortly after flowering
provides subsidy on purchase of seeds & on cost for production of seeds for green manure plants

Types

Leguminous plants

Nitrogen fixing ability
Ex. Cowpeas, Soyabeans

Non-leguminous plants

for weed suppression & addition of biomass to the soil
Ex. Sudan grass, Millets, Sorghum and Buckwheat

Advantages

Helps in soil improvement and soil protection
Provides forage for pollinating insects
Deep rooting properties → Increase aeration of soil+ Efficient at suppressing weeds
Fix nitrogen in soil, thus Less chemical fertilizers are required
Provides habitat for predatory beneficial insects which kill and eat harmful insects thus less pesticides are required