Land leveling or land grading for irrigation is modifying the surface relief of a field to a planned grade to provide a more suitable surface for efficiently applying irrigation water. Normally land leveling requires moving a lot of earth over several hundred feet. This should not be confused with land planning, land smoothing, or land floating. They are usually accomplished with special equipment to eliminate minor irregularities, and they do not change the general topography of the land surface. Rough grading is removing knolls, mounds, or ridges and filling pockets or swales in a field that is not to have a planned grade. Often no construction stake. are set and reliance is placed on the "eye" of the equipment operator to obtain the desired field surface. Rough grading is seldom adequate for lands to be surface irrigated.
U.S. Department of Commerce, "SCS Natinoal Engineering Handbook: Section 15, Irrigation, Chapter 12--Land Leveling" (1983). All U.S. Government Documents (Utah Regional Depository). Paper 513.