Question

Microbes can be used to decrease the use of chemical fertilizers and pesticides. Explain how this can be accomplished.

Answer 1

Microbes play important role in organic farming which is done without the use of chemical fertilizers and pesticides. Bio-fertilisers are living organisms which help increase the fertility of soil. It involves the selection of beneficial micro-organisms that help in improving plant growth through the supply of plant nutrients. Bio-fertilisers are introduced in seeds roots or soil to mobilize the availability of nutrients. Thus they are extremely benificial in enriching the soil with organic nutrients. Many species of bacteria and cyanobacteria have the ability to fix free atmospheric nitrogen. Rhizobium is a symbiotic bacteria found in the root nodules of leguminous plants. Azospirillium and Azotobocter are free living nitrogen-fixing bacteria whereas Anabena Nostoc and Oscillitoria are examples of nitrogen-fixing cyanobacteria. Bio-fertilizers are cost effective and eco-friendly.
Microbes can also act as bio-pesticides to control insect pests in plants. An example of bio-pesticides is Bacillus thuringiensis which produces a toxin that kills the insect pests. Dried bacteruial spores are mixed in water and sprayed in agricultural fields. When larvae of insects feed on crops these bacterial spores enter the gut of the larvae and release toxins thereby it. Similarly Trichoderma are free living fungi. They live in the roots of higher plants and protect them from various pathogens. Baculoviruses is another bio-pesticide that is used as a biological control agent against insect and other arthropods.