Consider the following statements about organic farming
$I.$ Organic farming promotes the use of crop rotations and cover crops and encourages balanced host/predator relationships
$II.$ Integrated pest and weed management and soil conservation systems are valuable tools on an organic farm
$III.$ Organic farming protects the environment, minimize soil degradation and erosion and decrease pollution
Which of the statements given above are correct?
Which of the following groups of plants are highly useful in increasing soil fertility
Which one is a nonsymbiotic nitrogen fixer
Which of the following cyanobacteria can fix atmospheric nitrogen?
$I.$ Anabaena
$II.$ Oscillatoria
$III.$ Nostoc
Choose the correct option
Azotobacter and Bacillus polymyxa are