ABSTRACT PART one concerns basics of the erosion process in terms of particle dynamics, threshold condi-tions, particle flux, and the protective role of nonerodible elements. Part two is a procedure for evaluating wind-erosion effects on soil loss and, subsequently, on crop yields. In the procedure, a wind-erosion equation is used to predict potential annual loss, which is converted to crop-yield reduction per centimeter of erosion for wheat, grain sorghum, and corn. Where applied in the Oklahoma Panhandle (in 2 1/4 counties), the procedure resulted in estimated annual yield reductions of wheat and grain sorghum equivalent to a total crop failure on about 4,530 ha (11,200 acre, or 17.5 sections) of the 163 300 ha (403,500 acre) of cultivated sandy sur-face soils in the selected area. Wind erodes land every year in the United States, especially in the Great Plains and Far West and where there are coastal sands, organic soils, and interior sandy soils. The extent and degree of damage depends on soil, crop (cover), and climatic conditions existing at specific locations.