Effect of Different Mulches on Harvested Rainfall Use Efficiency for Corn (Zea maysL.) in Semi-Arid Regions of Northwest China

A three-year field experiment was conducted to determine how integrating different furrow-applied mulches would influence the yield and water use efficiency (WUE) for corn (Zea mays L.) cultivated under a plastic-covered ridge and furrow rainwater harvesting (PRFRH) system in semi-arid lands of China's Loess Plateau. The effect of the mulching treatments in combination with PRFRH was compared to the conventional flat (control, T1). The furrow-applied mulching treatments and their designation were: none or bare furrow (T2); liquid film (T3); 8% biodegradable film (T4); 10-cm thick layer of corn stover (T5); and 0.08 mm thick plastic film (T6). Corn was planted in the furrows on either side of the plastic-covered ridges of the plots for treatments T2 though T6. Soil moisture was measured gravimetrically on auger samples taken at 6 locations in each plot at intervals of 20 cm from the 0 to 200 cm depth. In all years, soil moisture storage at the 0–100 cm depth was significantly higher (p < 0.05) in the T2 to T6 treatment plots compared to T1. No such effect was observed for the 100–200 cm depths. The integrated use of PRFRH and furrow-applied mulching performed better than the bare furrow treatment increasing the three-year average grain yield and harvest index (HI). WUE decreases followed the order: T6 > T4 > T3 > T2 > T5 > T1, indicating that mulching most likely reduced soil evaporation losses and suggesting that integrated PRFRH + mulch systems has potential to increase crop sustainability in this semiarid region.