Question

What is algal biofertilizer?

Answer 1

Biofertilizers:

1. These are natural compounds that contain micro-organisms to enrich soil fertility to increase crop yield and plant growth.
2. Microbial inoculants like bacteria, algae, and fungi can be used in biofertilizers.
3. The biofertilizers having algae as an inoculant in them are known as algal biofertilizers.
4. Biofertilizers can be used to fix nitrogen in the soil or they are also used to grow soil micro-flora to enhance soil health.

Example of algal biofertilizer-

1. BGA ( blue-green algal ) biofertilizers are used in fields to fix atmospheric nitrogen into the soil in organic form.
2. BGA biofertilizers are not inhibited by the presence of any chemical fertilizers.
3. Heterocyst is used to fix nitrogen into the soil.

Advantages of algal biofertilizers:

1. The algal biofertilizers can increase crop yield by 10-14%.
2. Unlike chemical fertilizers they are eco-friendly.
3. Low-cost input is required and thus is cheaper.

Benefits of BGA as a biofertilizer:

1. BGA is a biological nitrogen fixer, which concentrates the soil with organic matter and lowers the C: N ratio.
2. Other uses of BGA are to improve the solubilization of immovable phosphates and to produce growth-promoting substances in soil.
3. They improve the physical, chemical, and biological properties of the soil and contribute to long-term soil fertility.
4. BGA has been reported to lower soil pH and help the soil retain exchangeable calcium.
5. It has been reported that Nitrogen availability, particularly in the rice fields, to plants is increased due to the application of BGA.
6. In India, BGAs such as Anabaena, Nostoc, and Carotrix are generally predominant and are widespread in rice-growing areas, with the exception of some acidic soils in Kerala, Assam, and Tamil Nadu. Other forms such as Cylindrosporum, Tolypothrix, Scytonema, and Aulosira had a local distribution.
7. The prevalence of soils containing blue-green algae in India varies from 7% to 80% depending on the state.