Why are cyanobacteria considered useful in paddy fields ?
Cyanobacteria are autotrophic microbes widely distributed in aquatic and terrestrial environments many of which can fix atmospheric nitrogen(they contain heterocyst) e.g. Anabaena, Nostoc, Oscillatoria, etc. In paddy fields, cyanobacteria serve as an important biofertiliser and increases yield by $50 \%$. Blue green algae also add organic matter to the soil and increase its fertility.
Azolla possesses symbiotic association with
Crop rotation is carried out for
How do microbes reduce the environmental degradation caused by chemicals ?
Definitions / Explanation : Biofertiliser
Match the columns :
Column - $I$ | Column - $II$ |
$(a)$ Mycrrohiza | $(1)$ Rhizobium |
$(b)$ Bt | $(2)$ Nucleopolyhydro virus |
$(c)$ Root nodules | $(3)$ Phosphorus |
$(d)$ Baculo virus | $(4)$ Bt -Cotton |