Effect of Simulated Plow‐sole on Water Uptake and Yield of Dryland Wheat1

Yield of dryland crops grown on stored water is determined by water use from the profile which, in turn, is related to the extent of root proliferation in different layers. Plow‐soles of high strength may retard root growth and adversely affect crop production. We determined the effect of initial profile water storage and soil compaction below the seed on the growth and the yield of dryland wheat, (Triticum aestivum L.) in field experiments during 1970–71 and 1971–72. Compaction reduced water use from deeper layers and decreased grain yield during both years. Evidently, it retarded root growth through increased soil strength. Compared with lower initial water storage, higher initial water storage in the profile resulted in more vigorous plants, deeper rooting, greater water use from lower soil layers and higher yields. The results suggest that for greatest yields, compact layers below the seed must be loosened by tillage to permit deeper rooting. Also, in the absence of early season rain, a small supplementary irrigation to the young crop may stimulate deeper rooting and increase water use from lower layers.