Microbes As Biofertilizers

Organic farming is increasing the production of pollutant-free crops. It involves the use of biofertilizers and biopesticides which increases the nutrient quality of the crop and controls any kind of pest and pathogen.

Biofertilizers are microorganisms that add to the nutrient quality of the soil. Bacteria, fungi, and algae are some of the beneficial microorganisms that help in improving the fertility of the soil.

There are various types of biofertilizers.

  • Free-living nitrogen-fixing bacteria like Azotobacter, and Rhodospirillum.
  • Free-living nitrogen-fixing Cyanobacteria like Anabaena, and Nostoc.
  • Loose association of nitrogen-fixing bacteria like Azospirillum.
  • Symbiotic nitrogen-fixing bacteria like Rhizobium, and Frankia

Types of Biofertilizers

  • Rhizobium: They form root nodules in leguminous plants and fix the atmospheric nitrogen into an organic form. Rhizobium also has no negative effect on soil quality and improves the quality, nutrient content, and growth of the plant.
  • Azotobacter: These are free-living nitrogen fixers found in all types of upland crops. These not only fix nitrogen but also provide certain antibiotics and growth substances to the plant.
  • Azospirillum: Unlike Azotobacter, these can be used in wetland areas. They are found inside the roots of the plant (non-free-living) where they fix the atmospheric nitrogen.
  • Blue-green algae: These are free-living nitrogen-fixing Cyanobacteria that are present only in wet and marshy lands. However, they do not survive in acidic soil.
  • Mycorrhiza: It is a symbiotic association between the fungi and the roots of a plant. The mycorrhizal fungi play an important role in binding the soil together and improves the activity of the microbes. The fungi draw water and nutrients from the soil thereby increasing the plant productivity. It also helps the plant to survive under various environmental stresses.

Importance of Biofertilizers

  • Biofertilizers are eco-friendly and are not harmful to the environment.
  • These improve the soil quality thereby increasing plant productivity.
  • The farmers can prepare the inoculum of these microbes and inject them into the plants when required.
  • They produce growth promoting substances in the soil.
  • Biofertilizers can be used in semi-arid areas also.

Biofertilizers are the perfect alternative to chemical fertilizers. The chemicals not only harm the soil and its productivity but also harm the living organisms consuming the crops grown on that soil. Therefore, the scientists had discovered the use of microorganisms as fertilizers.

Biofertilizers have gained recognition over the years and are being implemented on a large scale to increase agricultural productivity without harming human health.

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Practise This Question

With respect to the following statements, choose the correct answer.
i.Food security depends on both, the availability of food and access to it.
ii.Mixed farming degrades the nutrient quality of the soil.
iii.Fertilisers are commercially produced plant nutrients.