Correct Answer - Option 4 : All 1, 2 and 3
The correct answer is All 1, 2, and 3.
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Based on the type of microorganism, the bio-fertilizer can also be classified as follows:
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Bacterial Biofertilizers: e.g. Rhizobium, Azospirilium, Azotobacter, Phosphobacteria.
- Fungal Biofertilizers: e.g. Mycorrhiza
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Algal Biofertilizers: e.g. Blue-Green Algae (BGA) and Azolla.
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Actinomycetes Biofertilizer: e.g. Frankia.
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Arbuscular Mycorrhizal Fungi (AMF) constitute a group of root obligate biotrophs that exchange mutual benefits with about 80% of plants.
- They are considered natural biofertilizers, since they provide the host with water, nutrients, and pathogen protection, in exchange for photosynthetic products.
- Azotobacter:
- Azotobacter is a free-living nitrogen-fixing bacterium, which is used as a biofertilizer in the cultivation of most crops.
- The shelf life of the biofertilizer is six months from the date of manufacture.
- The Process requires a locally available plant, machinery and raw materials for manufacture.
- Azospirillum:
- It is considered as safest bacteria that can be used as a biofertilizer at the commercial level for several crops, especially cereals or grasses including wheat and rice which are of economic importance for the whole world.
- Some of its species are reported for phosphate-solubilizing ability and high salt tolerance.
- Azospirillum bacteria can promote plant growth.