Question

Explain the inter relationship between organic farming and biofertilizers, with the help of any three suitable examples.
[5 marks]

Answer 1

Organic farming is a practise of agriculture where no chemical fertilisers or chemical pesticides are employed. It employs organic manures like animal dungs, dried leaves and other plant and animal wastes. [1 mark]
Biofertilzers are micro-organisms that enrich the nutrient quality of the soil. [1 mark]

Examples :

• Nodules on the roots of leguminous plants formed by the symbiotic association of Rhizobium. These bacteria fix atmospheric nitrogen into organic forms, which is used by the plant as nutrient. This helps to replace the chemical nitrogenous fertilisers. [1 mark]
• Mycorrhizae are symbiotic associations between fungi and the roots of plants. Fungal symbiont in mycorrhizal associations absorbs phosphorus from soil and passes it to the plant. [1 mark]
• Cyanobacteria are autotrophic microbes widely distributed in aquatic and terrestrial environments many of which can fix atmospheric nitrogen and enrich the soil, e.g. Anabaena, Nostoc, Oscillatoria. [1 mark]