Incorporation of ridge and furrow method of rainfall harvesting with mulching for crop production under semiarid conditions

A plastic-covered ridge and furrow rainfall harvesting (PRFRH) system combi ned with mulches was designed to increase water availability to crops for i mproving and stabilizing agricultural production in the semiarid Loess regi on of northwest China. The system was built by shaping the soil surface wit h alternate ridges and furrows along the contour. The plastic-covered ridge s served as a rainfall harvesting zone and furrows as a planting zone. Some materials were also used to mulch the furrows to increase the effectivenes s of the harvested water. This system can make better utilization of light rain by harvesting rainwater through the plastic-covered ridge. The field e xperiment (using corn as an indicator crop) showed that grain yields in the PRFRH system with mulches in 1998 and 1999 were significantly higher than the controls. with an increase of 4010-5297 kg per ha (108-143%). In most t reatments, the water use efficiencies (WUE) were in excess of 2.0 kg m(-3). The WUE values of corn in this system were 1.9 times greater than the cont rols in 1998 and 1.4 times greater than the controls in 1999. The plastic-c overed ridge led to a yield increase of 3430 kg per ha (92%) in 1998 and of 1126 kg per ha (21%) in 1999 compared with the uncovered ridge. On average , the additional mulches in the furrow brought about a yield increase of 8- 25%. Based on the results of this study and other researches, this techniqu e can increase corn grain yield by 60-95% in drought and average years, 70- 90% in wet years, and 20-30% in very wet years. The PRFRH system had the po tential to increase crop yield and produced greater economic benefit, there fore it could be used in regions dominated by light rainfall of low intensi ty where crops generally fail due to water stress. (C) 2001 Published by El sevier Science B.V.