Hard Red Winter Wheat Production on Conservation Bench Terraces
1982
Mickelson, Rome H.
Conservation bench terraces were cropped to winter wheat (Triticum aestivum L.) in both annual and summer fallow cropping systems. Leveled benches did not support annual cropping of winter wheat. In 2 of 4 years, available water in the surface 30 cm of soil at planting time had to average at least 3.3 cm for successful wheat establishment, and yields were 21% less than the fallowed contributing areas. Summer fallowing benches increased the amount of available soil water 1.7 times at planting and resulted in 18% greater wheat grain yields compared to yields on the fallowed contributing areas. Leveling, with or without runoff contribution, significantly increased available soil water and winter wheat yields. Lengths of contributing area did not significantly influence depth of runoff in the benches. During the course of this study, there was never enough runoff to completely inundate the leveled benches. Regression analysis of grain yield and water data predicted a maximum yield of 2,800 kg/ha with 69 cm of available water. This amount was available in only one year of the study with summer fallow and zero years with continuous cropping. Since the level benches were never inundated and the water supply for maximum yield was seldom attained, conservation bench terraces with ratios of contributing area to level-bench area of 3:1 were effective for controlling erosion in the semiarid region of the west-central Great Plains.
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