Which of the following is used as biofertiliser?
$I.$ Cyanobacteria
$II.$ Yeast
$III.$ Symbiotic bacteria
$IV.$ Free living bacteria
Choose the correct option
$I, II$ and $III$
$I, III$ and $IV$
$II, III$ and $IV$
$I, II$ and $IV$
The best fertilizer for paddy is
Aquatic fern which is an excellent biofertilizer
Azolla is used as a biofertiliser because it
What would happen if oxygen availability to activated sludge flocs is reduced ?
Which one of the following is not a biofertilizer?