Effects of conservation tillage on soil wind erosion characteristics in the Hexi oasis irrigational area

In arid areas, conservation tillage has the important advantage over conventional tillage reduction of soil erosion. Up to now, there have been few reports on effects of conservation tillage on soil wind erosion in the Hexi oasis irrigational area of China. A spring wheat field experiment was conducted to investigate the effects of different conservation tillage measures on field sediment discharge, wind erosion depth, wind erosion sediment granulometric composition, and wind speed in the Hexi oasis irrigational area, Gansu Province, Northwest China. The conservation tillage measures adopted in this study over three years included no-tillage with no stubble mulching (NT), no-tillage with stubble mulching (NTS), standing stubble (SS), and stubble overwhelm (SO), with conventional tillage (CT) as the control. The results showed that a sediment discharge of 0-30 cm could sensitively reflect the differences in sediment discharge among different tillage measures. Compared with CT, the sediment discharge of 0-30 cm decreased by 17.4%-46.7% in NT, 21.7%-45.2% in NTS, 24.7%-48.2% in SS, and 10.7%-42.4% in SO. The wind erosion depth was 1.22-1.44 mm for conventional tillage, and zero for each conservation tillage. Compared with CT, the wind erosion sediment granulometric composition of conservation tillage was no significant change, but the proportion of size of fine-grained soil (< 0.063 mm) had a decreasing tendency. The wind speed at 20 cm depth was significantly reduced by 24.1%-39.5% in SS and non-significantly reduced under other conservation tillage measures. In summary, different conservation tillage measures can control soil wind erosion to different extent in the Hexi oasis irrigational area; standing stubble was the most optimal conservation tillage measure and proved suitable for application in this area.