Midseason Soil Water Recharge for Corn in the Northwestern Corn Belt
1987
Johnson, Bradley S. | Blake, George R. | Nelson, Wallace W.
Incomplete soil water recharge between fall harvest and spring planting, and insufficient growing-season precipitation limit plant growth in southwestern Minnesota. Our objectives in this study were to test the hypotheses that (i) corn (Zea mays L.) production on a fine-textured soil of high water-holding capacity may be increased with irrigation, and (ii) that a single application of water at midseason to partially recharge the soil water reservoir would be as beneficial to the crop as more frequent, smaller additions. Treatments consisting of irrigation timing and amounts were established in field studies conducted from 1979 to 1983 on Nicollet clay loam (Aquic Hapludoll). Soil water depletion to 0.9 m was evident during only 2 yr (1980 and 1981). A shallow water table was present in 1979 and 1980 but was not detected within 2.0 m of the soil surface from 1981 to 1983. Despite wet soil conditions and above-normal precipitation, positive and significant grain yield responses to the addition of supplemental water were observed each year except 1982. Grain yields with a single application of 76 mm at midseason exceeded those with natural precipitation by 1.57, 2.73, and 0.72 Mg ha⁻¹ in 1979, 1980, and 1983, respectively. No difference in grain production was noted between single midseason applications of 76 mm of water and optimum irrigation (application of 38 mm at 50% depletion of plant-available water to a soil depth of 0.9 m). The economic feasibility of irrigation on Nicollet clay loam appears to be questionable based on yield responses to supplemental water from 1979 to 1983.
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