Land Forming Effects on Dryland Sorghum Production in the Southern Great Plains

Abstract

AbstractThe effectiveness of selected low‐cost, water‐conserving land forming systems in preventing runoff and increasing dryland grain sorghum [Sorghum bicolor (L.) Moench] yields on Pullman clay loam was evaluated for 4 years (1975–1978) at Bushland, Tex. Systems investigated were mini‐bench terraces (5 m wide), conservation mini‐bench terraces (9 m wide with a ratio of watershed to level bench area of 1:1), and three configurations of contour furrows. Runoff was measured from conventional graded furrows (0.25% grade) that were used for the check treatment. Total runoff for the 4 years was 258 mm, about 15% of total precipitation. All systems that retained runoff on the field produced significantly greater yields and had greater water‐use efficiencies than the graded furrow system. Grain yield and water‐use efficiency were significantly greater with mini‐bench terraces than with any other treatment. Mean annual grain yield on mini‐bench terraces was 2,380 kg/ha, compared to 1,210 kg/ha on conventional graded furrows. Minibenches, conservation mini‐benches, and large contour furrows controlled erosion and retained all precipitation from a storm of 75‐year expected frequency. In that storm, conventional furrows overtopped and failed to retain runoff.