Effects of soil managements on surface runoff and soil water content in jujube orchard under simulated rainfalls

Abstract

Inappropriate soil management on the Chinese Loess plateau has induced significant soil erosion, and improvements were obtained with cover crops, whereas few studies were reported about orchard soil management. This study investigated effects of five soil management (SM) practices on surface runoff and soil water content, which were (i) full ground mulching with jujube branches (BM), (ii) strip tillage only (ST), (iii) jujube branch mulch+strip tillage (BMT), (iv) jujube branch mulch+strip white clover (Trifolium repens L.) cover (BMWC), and (v) no cover (NC) as a control. Six microplots (with a length of 200cm, width of 80cm and depth of 80cm) were subjected to artificial rain during the growing seasons from 2011 to 2013. The variables about runoff and sediment evolution as well as soil water content were studied. Results showed that: (i) the time to runoff initiation was significantly shorter under NC than in other treatments, and the runoff plateau, total runoff volume and sediment yield were highest under NC. Compared with NC, there was over 60% reduction in runoff and 80% reduction in sediment load under other treatments, (ii) runoff and sediment discharge increased linearly under NC before reaching the peak value, while it increased step-wise in the other treatments, (iii) soil water content (θ) and soil water storage increase (SWI) were significantly greater under BM than others; The 2-year (growing season of 2011 and 2012) mean θ and SWI were the lowest under NC, (iv) overall, BM increased soil water content, and decreased runoff and sediment yield, and thus could potentially solve water shortage and soil erosion problems in rainfed jujube orchards on Chinese Loess Plateau.