Effects of Subsoiling and Irrigation on Corn Production

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Abstract
Deep tillage and irrigation are two soil management techniques that have been used separately to alleviate water shortages for crops growing on soils having root restricting tillage pans. The purpose of this study was to evaluate the effects of in‐row‐subsoiling (S), irrigation (I), and in‐row‐subsoiling plus irrigation on corn (Zea mays L.) production on Wagram soil (fine‐loamy, siliceous, thermic Arenic Paleudults) having a dense tillage pan. Main plot treatments were: CD (conventional tillage [double disking], dryland); CI (conventional tillage, irrigated when soil water pressure [SWP] at the 0.25‐m depth reached −40 kPa); SD (in‐row‐subsoiled and bedded, dryland); and SI (in‐row‐subsoiled and bedded, irrigation when SWP < −40 kPa at 0.30‐m depth). Total growing season precipitation in 1979, although poorly distributed, was near normal; 1980 and 1981 were both drought years. The 3‐yr mean amounts of irrigation water applied were 179 mm for the CI and 145 mm for the SI treatments. The CI, SD, and SI treatments always had significantly higher yields of grain and stover and lower numbers of barren plants compared to treatment CD. Maximum corn height was greatest (2.68 m) for treatment SI and leaf area indices for treatments CI, SD, and SI were 23, 28, and 36% greater, respectively, than the 2.56 value for CD. Mean grain yields for treatments CI, SD, and SI were 215, 197, and 277% greater, respectively, than the 2.58 Mg ha−1 CD yield. Root length and root mass in the 0.1 to 0.6‐m soil depth were greater for the dryland treatments. Apparent irrigation water use efficiencies were 0.031 and 0.014 Mg ha−1 mm−1 for treatments CI and SI, respectively. Estimates of subsoil water utilization using neutron attenuation and tensiometer data were 50 mm yr−1 which resulted in an apparent subsoil water use efficiency of 0.10 Mg ha−1 mm−1.
Funding Information
  • U.S. Department of Agriculture (58‐7B30‐9‐77)