The chemical substances which destroy the weeds but do not harm the crop are called

Beating the cut stalks against machine called _____

______ plants have root nodules associated with symbiotic bacteria.

One of the biggest canal project in India is

______ irrigation is used where the soil cannot retain water for a long time.

The method in which the field is just filled with water is called

Grains are separated from the stallks by the process of

______are the undesirable plants growing naturally along with crops.

Before ______ the land must be watered.

________ensures uniform irrigation.