不同覆盖处理对冬小麦气体交换参数及水分利用效率的影响

Effects of different mulching treatments on the gas exchange parameters and water use efficiency of winter wheat

为了探索半湿润灌区冬小麦在不同覆盖处理下水分利用的生理生态机制，该文采用秸秆覆盖和起垄覆膜沟内播种（膜垄）两种覆盖种植处理，研究了冬小麦叶片水平气体交换诸参数的日变化和生育期变化，分析了群体水平和产量水平的水分利用效率。结果表明：与不覆盖处理相比，在灌浆期秸秆覆盖和膜垄处理能有效提高冬小麦14：00以后的光合速率，膜垄处理能极显著提高冬小麦12：00后叶片水平水分利用效率，秸秆覆盖处理降低了10：00～14：00的蒸腾速率，从而能提高中午的水分利用效率；两种覆盖处理均能提高冬小麦生育后期的叶片水平光合速率及其水分利用效率，但在产量及群体水平水分利用效率上并无优势；膜垄处理通过加大对土壤水分的利用而显著提高产量，秸秆覆盖处理由于群体减小而导致减产。

A field experiment was conducted for winter wheat （Triticum aestivum L. ） to explore the physiological and ecological mechanism of water utilization under different mulching treatments in semi-humid irrigated area. Daily variation and growth stage variation of gas exchange parameters of winter wheat were studied under straw mulch and ridge covered with plastic film treatments. Water use efficiency at population and yield level were analyzed. Results show that, compared with no-mulch treatment, the two mulch treatments increase the photosynthetic rate after 14 ： 00. Ridge covered with plastic film treatment improves the water use efficiency at leaf level （WUEL） after 12 ： 00 significantly and straw mulch treatment improves WUELduring 10 ： 00～14 ： 00 while decreases transpiration rate. The two mulch treatments increase the photosynthetic rate and WUEL in the later growth stage but have contribute to dominance on WUE at population level and yield level. The yield of winter wheat increases significantly under the ridge covered with plastic film result from high soil water utilization. The reason of the yield reduction under straw mulch is mainly low tillering ability.