Farmers in the desert southwest are continually facing problems of allocation of water, their most vital resource. Demands that are larger than supplies have resulted in the need for a well planned future regarding the use of water if economic agricultural development is to continue. The study of the Pecos River Basin, New Mexico, was to furnish information concerning the geographic location of irrigated cropland with soil and water problems affecting income expectancies. The Cornell system of economic land classification was used as a basis to delineate those areas having slight (Class I), moderate (Class II), or severe (Class III), limitations with respect to soil and water quality and/or quantity. Soil and water maps and reports, and an extensive field survey, were combined to construct the maps. By transferring irrigation water from Class III to Class II cropland, especially where water quality is a problem, and to potential Class I land, the economic return per acre-foot of irrigation water in the basin could be increased. (Author)