Effects of Different Tillage Systems on Soil Properties, Root Growth, Grain Yield, and Water Use Efficiency of Winter Wheat (Triticum aestivum L.) in Arid Northwest China

Studies on root development, soil physical properties, grain yield, and water-use efficiency are important for identifying suitable soil management practices for sustainable crop production. A field experiment was conducted from 2006 through 2008 in arid northwestern China to determine the effects of four tillage systems on soil properties, root development, water-use efficiency, and grain yield of winter wheat (Triticum aestivum L.). The cultivar Fan 13 was grown under four tillage systems: conventional tillage (CT) without wheat stubble, no-tillage without wheat stubble mulching (NT), no-tillage with wheat stubble standing (NTSS), and no-tillage with wheat stubble mulching (NTS). The soil bulk density (BD) under CT system increased gradually from sowing to harvest, but that in NT, NTSS, and NTS systems had little change. Compared to the CT system, the NTSS and NTS systems improved total soil water storage (0-150 cm) by 6.1-9.6 and 10.5-15.3% before sowing, and by 2.2-8.9 and 13.0-15.1% after harvest, respectively. The NTSS and NTS systems also increased mean dry root weight density (DRWD) as compared to CT system. The NTS system significantly improved water-use efficiency by 17.2-17.5% and crop yield by 15.6-16.8%, and the NTSS system improved that by 7.8-9.6 and 7.0-12.8%, respectively, compared with the CT system. Our results suggested that Chinese farmers should consider adopting conservation tillage practices in arid northwestern China because of benefits to soil bulk density, water storage, root system, and winter wheat yield.