Question

The biofertilizers are

• A. Anabaena and Azolla
• B. cow dung, manure and faryard waste
• C. quick growing crop ploughed under soil
• D. none of these.

Answer 1

The Correct Option is A

Biofertilizers are organisms which bring about nutrient enrichment of the soil. Azotobacter is a free living, aerobic, nitrogen fixing bacteria. Anabena is a nitrogen fixing cyanobacteria that occurs in both free living and symbiote associations with Azolla, Cycas roots etc. Rhizobium lives symbiotically in root nodules of legumes and non-legumes. Vesicular-arbuscular mycorrhiza (VAM) is an example of endomycorrhiza in which fungal hyphae penetrate the cortical cells of grasses to form vesicles.

Answer 2

Fertilizers are substances that are used to enhance the fertility of cultivated land, which leads to better growth and yield of crops. Generally, chemical fertilizers are used by farmers to reduce and affect soil fertility over time and also pose harm to consumers. To solve this problem, biofertilizers are used as natural fertilizers without any chemical composition. They are made of bacteria, fungal, or algal cultures that are connected with symbiotic relations to leguminous plants. These microbes are advantageous in fixing atmospheric nitrogen for plants. Also, they stop the pathogenesis of plants.

Some microbes live in symbiotic relations while others have free living. Both are important to improve soil quality, plant health, and nutrition.

To know which of the species is/are used as biofertilizers, let us understand each species one by one.

-Funaria is a moss species. They form mat-like structures as they grow in abundant clusters. These are autotrophic plant-like organisms that naturally grow in moist shady locations. These are not used as biofertilizers because their growth can lead to stagnant water conditions which can harm crops due to nutrient exhaustion.

-A Fern is a vascular plant that is reproduced by spores. Not being a microbe, It's not used as a biofertilizer. Also, it has no significance in fertility enhancement, nitrogen fixation, etc.

-Anabaena is a Cyanobacteria species. It has nitrogen-fixing properties. It lives with other plants like mosquito ferns. It also releases some neurotoxins that help to protect the crops from grazing pressure by animals.

-The fungus is a spore-producing organism that usually grows over dead and decaying matter. Many fungal species are used as biofertilizers but not all fungus is biofertilizers.

Therefore, the right answer is option A( Anabaena and Azolla).