Self-propelled center-pivot sprinkler systems have become very popular because of their low labor requirements and ability to economically irrigate rolling sandhills. This equipment applies water uniformly to the soil surface, but the water application rates greatly exceed the infiltration capability of most soils causing water to move on the soil surface from local high areas and slopes to nearby low spots. The resulting nonuniformity of irrigation results in reduced crop yields, waste of water, and fertilizer leaching. This problem was investigated using a laboratory infiltrometer, a mathematical model, a field sprinkler infiltrometer, and field investigations under operating systems. Recommendations were developed to reduce or eliminate the problem through improved system design, special field preparation and farming techniques, and improved operating procedures. (Author)