Aquatic fern which is an excellent biofertilizer
Salvinia
Azolla
Marsilea
Pteridium
A water fern, which is used as a green manure in rice fields is
Which of the following is free living aerobic and nonphotosynthetic nitrogen fixing bacterium
Leghaemoglobin occurs in
Give scientific reasons : The pressure on use of organic farming and biotic fertiliser has been increased.