Biofertilisers are the organisms that enrich the nutrient quality of the soil. Which of the following is not a source of biofertiliser ?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Baculoviruses
Option (1) Bacteria — A source of biofertiliser. Rhizobium in root nodules, and free-living Azospirillum and Azotobacter, fix nitrogen.
Option (2) Fungi — A source of biofertiliser. Mycorrhizal fungi such as Glomus help plants absorb phosphorus.
Option (3) Baculoviruses — Not a source of biofertiliser. Baculoviruses attack insects; they are biocontrol agents, used against pests.
Option (4) Cyanobacteria — A source of biofertiliser. Anabaena and Nostoc fix nitrogen, especially in paddy fields.
NCERT Extract:
Microbes as Biofertilisers – “… With our present day life styles environmental pollution is a major cause of concern. The use of the chemical fertilisers to meet the ever-increasing demand of agricultural produce has contributed significantly to this pollution. Of course, we have now realised that there are problems associated with the overuse of chemical fertilisers and there is a large pressure to switch to organic farming – the use of biofertilisers. Biofertilisers are organisms that enrich the nutrient quality of the soil. The main sources of biofertilisers are bacteria, fungi and cyanobacteria.”
Microbes as Biocontrol Agents – “… Baculoviruses are pathogens that attack insects and other arthropods.”