Question

Which of the following are examples of biofertilizers?
A. Green manure
B. Compost manure
C. BGA and VAM
D. Green manure and chemical fertilizers

Answer 1

A biofertilizer is a substance that includes living microorganisms that colonize the rhizosphere or the interior of the plant when applied to seeds, plant surfaces, or soil and promotes growth in the primary nutrient supply or availability of the host plant.

Complete answer:
Biofertilizers are micro-containing substances that help to promote plant and tree growth by increasing the supply of essential nutrients to plants. It includes live organisms, including mycorrhizal fungi, blue-green algae, and bacteria. Mycorrhizal fungi preferably extract minerals from the organic matter of the plant, while cyanobacteria are characterized by nitrogen fixation properties.
It protects the roots from soil pathogens and plays a key role in atmospheric nitrogen fixation. Nitrogen is a nutrient that is very important to the plant, and about 78% of the total atmosphere is nitrogen.
Rhizobium, Azotobacter, Azospirillum , and blue-green algae (BGA) are biofertilizers.
Blue-green algae is a bacterium that fixes free-living nitrogen. BGA has been proposed as a biofertilizer. VAM plays a major role in inducing plant growth. VAMs are symbiotic endophytic soil fungi that colonize about 80 percent of the roots of the plant. VAM is also used as a biofertilizer.
So, choice C- BGA and VAM is the correct answer.

Note: Inoculant Rhizobium is used for leguminous crops. Azotobacter may be used for crops such as wheat, maize, mustard, cotton, potatoes, and other vegetable crops. The symbiotic nitrogen fixation of Rhizobium with legumes contributes significantly to the total nitrogen fixation. Rhizobium inoculation is a well-known agricultural method to ensure adequate nitrogen. Anabaena contributes up to 60 kg of nitrogen season in conjunction with Azolla water fern and also enriches soils with organic matter.