Correct option (d) all of these
Explanation :
Growing of alternate crops in the similar seasons on the same piece of land is called crop rotation. Crop rotation is helpful in improvement of soil fertility because of the following reasons.
(i) It decreases the chances of soil borne **** because the pathogens are unable to find the same host next Year.
(ii) It avoids deficiency of minerals from one level because the roots of different crops penetrate to different depths in the soil.
(iii) Crop rotation maintains the nitrogen fertility of the soil when legume crop is rotated with others.
(iv) It increases soil porosity because of the *** of roots of different crops to various depths.
