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Higher irrigation quota for conventional farming causes substantial conflicts between water supply and demand in agriculture, and wind erosion near soil surface is one of the major causes of farmland degradation and desertification in arid areas. This research investigated the effect of the amounts of irrigation in combination with tillage practices on soil evaporation (E), water consumption (ET) characteristics, and grain yield performance and water use efficiency (WUE) for wheat (Triticum aestivum L.) intercropped with maize (Zea mays L.) in strip planting in an Oasis region. The field experiment, conducted at Wuwei station during 2008–2010, had two tillage systems (reduced tillage with wheat stubble retention vs. conventional tillage without stubble retention), and three (low, medium, and high) levels of irrigation, in a randomized complete block design. Averaged across three years, soil evaporation with medium and high levels of irrigation was 6.8% and 5.4% greater than that with low level of irrigation, respectively. Total water consumption of wheat/maize crops under the medium and high irrigation levels was 8.5% and 18.5% greater, respectively, than that under low irrigation. However, grain yields were similar under the medium and high levels of irrigation, so was WUE. The effect of tillage on the wheat/maize intercropping was inconsistent across years or among treatments: soil moisture at harvest was 3.0–7.6% greater in the fields with reduced tillage compared with those with conventional tillage in 2008 and 2009, but no difference was found in 2010; the E/ET ratio of reduced tillage was 9% lower than the ratio under conventional tillage in 2008, 3% higher in 2010, but no difference between the two tillage systems in 2009. Across three years, there was a general trend that the WUE of the wheat/maize intercropping system with reduced tillage was greater (by 4–11%) than that with conventional tillage. We conclude that a medium level of irrigation is sufficient to achieve crop yields and WUE equivalent to those under high level of irrigation, provided that a reduced tillage practice is applied to the wheat/maize intercropping in Oasis areas.
