Tillage and Straw Management Impacts on Soil Properties, Root Growth, and Grain Yield of Winter Wheat in Northwestern China

Studies on root development, soil physical properties, and yield are important for identifying suitable soil management practices for sustainable crop production. Field experiments with winter wheat (Triticum aestivum L.) were conducted in silt loam soil from 2005 through 2007 in arid northwestern China to determine the effects of five tillage systems on soil strength, soil moisture, crop root development, grain yield, and yield components. The five treatments were conventional tillage without wheat stubble (T), conventional tillage with wheat stubble incorporated (TSI), no-tillage without wheat stubble mulching (NT), no-tillage with wheat stubble standing (NTSS), and no-tillage with wheat stubble mulching (NTS). Compared with the T treatment, the NTSS and NTS treatments improved soil water content in the 0- to 130-cm soil depth by 10 to 17% and 15 to 25%, respectively (P < 0.05). The NTSS treatment also increased mean root length density (RLD) by 8 to 40% and crop yield by 13 to 24%, and NTS by 17 to 48% and 17 to 31%, compared with the T treatment. Yield components analysis indicated that thousand-grain weight and spike density considerations helped explain the grain yield increases under conservation tillage systems (NT, NTSS, NTS), while spike length, number of grains per spike, and grain weight per spike failed to contribute to the model. Our results suggest that Chinese farmers should consider adopting conservation tillage practices in arid northwestern China because of benefits to soil strength, water storage, RLD, and wheat yield.