Traffic and Tillage Effects on Soil Water Conservation and Winter Wheat Yield in the Loess Plateau, China

In semi-humid Loess Plateau of northern China, water is the limiting factor for rain-fed crop yields. In this region, long-term traditional ploughing with straw removal has resulted in poor soil structure, water conservation and crop yield. Controlled traffic, combined with no-till and straw cover has been proposed to improve soil water conservation and crop yield. From 1999 to 2007, a field experiment on winter wheat was conducted in the dryland area of Loess Plateau of northern China, to investigate the effects of traffic and tillage on soil water conservation and crop yield. The field experiment was conducted using two controlled traffic treatments, no tillage with residue cover and no compaction (NTCN), shallow tillage with residue cover and no compaction (STCN) and one conventional tillage treatment (CK). Results showed that controlled traffic system reduced soil compaction in the top soil layer, increased soil water infiltration. The benefit on soil water infiltration translated into more soil conservation (16.1%) in 0-100 cm soil layer in fellow period, and achieved higher soil water availability at planting (16.5%), with less yearly variation. Consequently, controlled traffic system increased wheat yield by 12.6% and improved water use efficiency by 5.2%, both with less yearly variation, compared with conventional tillage. Within controlled traffic treatments, no tillage treatment NTCN showed better overall performance. In conclusion, controlled traffic combined with no-tillage and straw cover has higher performance on conserving water, improving yield and water use efficiency. It is a valuable system for soil and water conservation for the sustainable development of agriculture in dryland China.