Which one of the following organisms can serve as a biofertilizer for rice crop?
- Blue-green algae
- Rhizobium sp
- Mycorrhizal fungi
- Azotobacter sp
Explanation
Option (a) is correct
- Blue-green algae (cyanobacteria such as Anabaena and Nostoc) fix atmospheric nitrogen in flooded paddy fields. They are particularly suitable for rice cultivation.
- Rhizobium – Works with legumes.
- Azotobacter – Used for non-leguminous upland crops.
- Mycorrhiza – Helps in phosphorus absorption but not primary nitrogen fixation for rice
