BIOFERTILIZERS

 

BIOFERTILIZERS

Bio fertilizers are artificially multiplied cultures of certain microorganisms that can improve soil fertility and crop productivity without polluting our environment. Some common microorganisms used as bio fertilizers are Rhizobium, Azotobacter, Azospirillum, Blue green algae (Cyanobacteria) etc. These microorganisms fix atmospheric nitrogen, converting insoluble phosphates into soluble and decomposable farm wastes, which results in the release of plant nutrients by their biological activities.

       Rhizobium forms nodules in the roots of legume plants and fixes atmospheric nitrogen symbiotically. Azotobacter is a free living nitrogen fixing bacteria present in soil which enhances the crop yield of cereals by fixing nitrogen non symbiotically. Anabaena & Nostoc belonging to Cyanobacteria are free living nitrogen fixing microbes mainly used in rice fields to enhance crop yield.

     These microbes are produced in large scale and used in crop fields as a bio- fertilizer to supplement the chemical fertilizers to maintain sustainability of the soil and environment. It is cheaper than chemical fertilizer.

Q 1.1 Bio fertilizers are used to maintain which element in soil:

 (a) Calcium    

 (b)  Magnesium

 (c)   Iron

 (d)   Nitrogen

 Ans- d

Q 1.2   Blue green algae are known as:

(a)     Bacteria

(b)    Algae

(c)     Lichen

(d)    Cyanobacteria

 Ans- d

Q 1.3 In which group of plants does Rhizobium form nodules?

Ans-legume plants

Q 1.4   Give one example of microbe which fixes nitrogen in cereal crops.

Ans- Azotobacter ,Anabaena & Nostoc

Q 1.5   How bio fertilizers are better than chemical fertilizers? Give two reasons.

Ans-   These microbes are produced in large scale and used in crop fields as a bio- fertilizer to supplement the chemical fertilizers to maintain sustainability of the soil and environment. It is cheaper than chemical fertilizer