Topsoil Depth, Fertility, Water Management, and Weather Influences on Yield
1991
Thompson, A. L. | Gantzer, C. J. | Anderson, S. H.
The productive capacity of a soil is generally related to topsoil depth. This study was conducted to determine the influence of topsoil depth, soil fertility, and water management on grain yield for corn (Zea mays L.) and soybean (Glycine max [L.] Merr.). A field experiment at Columbia, MO, was initiated in 1983 and maintained through 1987 on a Mexico silt loam (fine, montmorillonitic, mesic Udolic Ochraqualf). The study was conducted using a split-plot experiment for each crop. Main effects included topsoil (depth to claypan), soil fertility, and water management. Desurfaced plots were constructed having topsoil depths of 0, 125, 250, and 375 mm. Plots were either fertilized according to soil-test recommendations or unfertilized. Water management was either rain fed or with supplemental irrigation. Overall, corn yield was 5.7 times more sensitive than soybean to topsoil depth when averaged over both fertility and water management. The topsoil × soil fertility interaction was characterized by a 34% reduction in corn yield with topsoil depths < 125 mm in the fertilized treatments when averaged across water management. Similar yield reductions for unfertilized plots were observed but were linearly related to topsoil depth. The fertility × irrigation interaction described a multiplicative increase in corn yield when corn was both fertilized and irrigated. Only topsoil depth and water management significantly influenced overall soybean yield. Contribution of the Missouri Agric. Exp. Stn. Journal no. 11 240. Supported by Missouri Agric. Exp. Stn. Projects 479 and 396 and Grant 87-4 from the Missouri Dep. of Natural Resources in cooperation with NC-174 Project.
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