Question

Why is moisture retained longer in the soil if it is harrowed?

Answer 1

When the soil is not harrowed, there are large capillaries in it. Water in the soil rise up the capillary holes to the surface from where it evaporates continuously . Thus the soil continuously loses water. When harrowed, all these capillaries are destroyed , and so capillary suction stops together. Thus water is retained longer in the soil.