小麦玉米间作种植是甘肃省河西一熟制灌区的主要种植模式,对提高当地粮食产量发挥了重要作用。2种作物间作时,除了充分利用光、热资源外,单位面积养分和水分的充足供应也是保证高产的关键。河西地区主要依赖祁连山雪水灌溉,水资源量少,提高作物水分利用率是高效利用水资源的重要途径。通过河西干旱灌区小麦玉米间作的田间试验,研究了不同施氮量对小麦玉米间作水分利用及产量的影响。结果表明：不同施氮水平条件下,小麦带土壤中的含水量随施氮量的增加变化较小,而玉米带土壤中的含水量随着施氮量的增加逐渐降低。随着施氮量的增加无论小麦产量还是玉米产量都是先增加而后降低,施氮375 kg·hm-2时小麦玉米间作产量都达到最高,施氮562．5 kg·hm-2时产量反而有所降低,施氮量对小麦玉米间作的水分利用效率有显著影响,水分利用效率随施氮量的增加呈单峰变化趋势,施氮量超过375 kg·hm-2时,水分利用效率有所下降。图3,表1,参11。%Wheat and maize inter-cropping is the main cropping pattern in the irrigated area of Hexi corridor, Gansu Province, which plays an important role in improving the local grain yield. Besides the optimum use of light and heat resources, adequate supply of nu-trients and water per unit area are the other key factors ensuring high output for inter-cropping. Due to less water in Hexi region, melt-snow from Qilian Mountainhas has been mainly used for irrigation proposes. Therefore, the increasing crop water use efficiency is an important approach to efficient utilization of water resources. The influences of the different rates of nitrogen applied on water use and yield were studied in wheat and maize inter-cropping by field experiment in Hexi arid irrigated area. The results showed that compared to different nitrogen treatments, the soil water content in wheat belt changed little with the increase of nitrogen rates applied while maize belt′s soil water content was decreased. With the increase of nitrogen application, both wheat and maize yields increased first and then decreased. The yields of wheat and maize inter-cropping reached the highest when nitrogen fertilizer was applied to 375 kg·hm-2; on the contrary, the yield decreased when nitrogen fertilizer was 562. 5 kg·hm-2. Nitrogen rates had a significant effect on the water use efficiency of wheat and maize. The water use efficiency increased with the increase of nitrogen application with a single peak, over 375 kg·hm-2 nitrogen application, the water use efficiency was decreased.
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