In the method of irrigation, water is applied to a field by means of small, narrow field channel and is suitable for crops grown in rows. Since the water is not applied to the entire area, the consumption of water is less, is described by which method of irrigation?

The correct answer is B, furrow irrigation. In this method small narrow channels are run between the ridges on which a row crop stands, and only those channels are filled. The water reaches the roots from the side while the ridge tops stay dry, so less of the field is wetted and less water is used than in any flooding method. Maize, cotton, sugarcane, potato and vegetables are watered this way in the canal commands of Rajasthan.

Option A, flood irrigation, spreads water over the whole surface and is the most wasteful method. Option C, perennial irrigation, is not a field method at all but a description of a canal that supplies water through the year, as against inundation canals that run only in the flood season. Option D, basin irrigation, divides the field into level plots ringed by small bunds and is used for orchards and for close growing crops, not for row crops.