[Science] Bio Fertilizers & Green Manure: Meaning, use, advantages, disadvantages
For GS (Mains) Paper II.
- Examples of BioFertilizers:
- Pros and Cons
- Green Manure
- Examples of Green Manure
- Pros and Cons of Green Manure?
- a substance which contains living microorganisms
- 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.
Examples of BioFertilizers:
- blue green algae (BGA)
Pros and Cons
- It increases crop yield by 20-30%,
- replaces chemical nitrogen and phosphorus by 25%, and stimulates plant growth.
- It can also provide protection against drought and some soil-borne diseases.
- Bio-fertilizers are cost-effective relative to chemical fertilizers. They have lower manufacturing costs, especially regarding nitrogen and phosphorus use.
- environmentally friendly also helps to some extent cleanse the plant from precipitated chemical fertilizers.
- Their effects are is slower compared to chemical fertilizer.
- Difficulty to store: they’re sensitive to temperature and humidity changes.
- much lower nutrient density — requires large amounts to get enough for most crops
- requires a different type of machine to apply than chemical fertilizers
- sometimes hard to locate/purchase in faraway rural areas
- green manure is a type of cover crop grown primarily to add nutrients and organic matter to the soil.
- Typically, a green manure crop is grown for a specific period of time, and then ploughed under and incorporated into the soil while it is green or shortly after flowering.
- Government of India provides subsidy Subsidy on the purchased of seeds & cost on production of seeds for green manure plants.
Examples of Green Manure plants
||sudangrass, millet, sorghum, and buckwheat.
|Why are they used?
||for their nitrogen fixing abilities
||for weed suppression and addition of biomass to the soil.
Pros and Cons of Green Manure?
- soil improvement and soil protection.
- provides forage for pollinating insects.
- Root systems of many green manure crops to efficiently penetrate compact soils thus increasing the aeration of the soil.
- The deep rooting properties of many green manure crops make them efficient at suppressing weeds
- They fix nitrogen in soil, thus Less chemical fertilizers are required.
- provide habitat for predatory beneficial insects, they kill and eat the pests / harmful insects thus less pesticides are required.
- Leguminous plants require good amount of irrigation.
- The “time” factor: you cannot plant the primary marketable crop during green manuring phase.