A compact, coherent mass of soil ranging in size from 5 to 10 millimeters (0 20 to 0 39 inch) to as much as 200 to 250 millimeters (7 87 to 9 84 inches) produced artificially, usually by the activity of man by plowing, digging, etc , especially when these operations are performed on soils that are either too wet or too dry for normal tillage operations ADVANCE\x 540
A compact, coherent mass of soil varying in size, usually produced by plowing, digging, etc , especially when these operations are performed on soils that are either too wet or too dry and usually formed by compression, or breaking off from a larger unit, as opposed to a building-up action as in aggregation