Wednesday, November 7, 2007 - 3:45 PM
306-10

Performance of Ridge and Furrow Water-Harvesting System in Loess Plateau of China.

Xinxiao Yu1, Derong Su1, Tian Yuan2, and Zhi Wang3. (1) Beijing Forestry University, Key Laboratory of Soil and Water Conservation of Ministry of Education of China, Beijing, 100083, China, (2) College of Chemical and Environmental Engineering, Beijing Technology and Business University, Beijing, 100037, China, (3) California State University-Fresno, 2576 E San Ramon Ave ST-24, Fresno, CA 93740

Ridge and furrow planting system (RFPS) for rain harvesting agriculture has been commonly practiced for decades in the Loess Plateau of northwest China resulting in significant improvements in soil and water conservation and economic returns. In the conventional RFPS, the ridge serves for planting and the furrow serves for water conservation. This study is focused on the reversed RFPS where the ridge serves for rain harvesting and the furrow for planting and water conservation. The relationships between the amount of harvested water versus ridge surface treatment and ridge-to-furrow ratio were quantified. Two types of ridge surface treatment (bare and plastic covered) and three ridge-to-furrow ratios (i.e., 30:60, 45:60 and 60:60 by width in cm) were studied experimentally. The results showed that the plastic covered ridges could harvest about 60% of precipitation compared to about 6% for the uncovered bare ridges in the study area with an annual precipitation of 263 mm (or 10.4 inches) varying between 150 mm (5.9 inches) and 400 mm (15.7 inches). Because of raindrop splashing from the plastic surfaces, the narrower ridges lost more water than the wide ridges. The wider ridges gained about 5% more runoff per 15-cm increase in the ridge width ranging from 30 cm to 60 cm (1 to 2 ft). Visual examination of the crop growth status indicated that the 60-cm wide, plastic-covered ridges produced the best promise for higher crop yield. Therefore, the plastic-covered ridges with the highest ridge-to-furrow ratio (60-cm to 60-cm) were recommended for applications in this region.