Ditch, in agriculture, a common fence, or inclosure, in marshes or other wet lands, where hedges cannot be conveniently planted.

Ditches are generally allowed six feet in width at the side of broad highways, and five feet in commons. But those trenches dug at the foot of the bank on which the quick is raised, are in general only three feet wide at the top, one at the bottom, and two feet deep. Thus, each side acquires a slope, which is of great advantage : for, in ditches made perpendicular, the sides are continually washing down; and if cattle descend into a narrow-bottomed ditch, they have no room to turn themselves, so as to crop and injure the quick. Where a ditch is four feet wide, it should be two and a half deep; and if it consist of five in width, it ought to be three in depth ; or if it be wider, the depth should be increased in proportion.