The Effects of Irrigation Application Depth on Corn Yield and Soil Moisture

Today\u27s technology has done much to decrease irrigation labor demands with higher investments in equipment. A center pivot irrigation machine is an example of an irrigation method that allows control over the amount of\u27 water applied with greatly reduced labor requirements. Irrigation with the center pivot system is often characterized by one to two inch irrigation application depths. These irrigation depths are often used to help avoid deep wheel tracks, to utilize the high initial infiltration rate of soil, and to minimize the variation in soil moisture in the soil profile. The general purpose of this study was to evaluate the effect of various irrigation management practices on crop response and the fate of soil moisture. The specific objectives of the reported investigation were to evaluate the effects of 1, 2, and 3 inch sprinkler irrigation application depths and l½, 2¼, and 3 inch furrow irrigation application depths on: (1) Corn grain yield, (2) Soil moisture storage and depletion, (3) Distribution efficiency (furrow irrigation only), (4) Water use efficiency. Corn grain yield was chosen to be the measure of crop response since corn is primarily harvested for grain under irrigated conditions in South Dakota. Soil moisture storage and depletion were evaluated to obtain moisture depletion patterns. Distribution efficiencies were determined to evaluate the uniformity of the furrow irrigations along the entire length of the irrigation run. Water use or total moisture depletion was measured to determine which irrigation practice utilizes water most efficiently