土下微膜覆盖与灌水管理对冬小麦水分利用与物质生产效果的影响

针对华北平原小麦生产水资源高耗与存量极度稀缺的问题,通过河北省两地大田试验,研究了全田土下微膜覆盖与不同灌水管理对冬小麦水分利用和物质生产效果的作用。结果表明,土下微膜覆盖条件下,冬小麦雨养或少量灌水消耗了占常规生产(对照)2/3~3/4的耗水量,生产了不少于7500 kg hm–2的籽粒产量;籽粒产量水分利用效率达到24.8~26.5 kg mm–1hm–2,较对照提高28.3%~41.0%。与对照相比,生物产量水分利用效率高峰由抽穗扬花期提前至拔节期,且提高1.3~2.7倍,雨养或少量灌水还可有效提高小麦收获指数。土下微膜覆盖下的土壤贮水消耗速度变缓,2 m土体贮水量播种时不小于600 mm就可满足小麦的全生育期耗水,壤质土壤供水量为212.2 mm,黏质土壤供水量为230.0 mm。土下微膜覆盖下,雨养或扬花前少量灌水能够显著促进花后20 d内的净光合速率,蒸腾速率减小同步显著提高光合水分利用效率,但在灌浆中期灌水则对提高净光合速率及光合水分利用效率无意义。在华北平原,全田土下微膜覆盖雨养或适时少量灌水是大幅降低小麦耗水和提高水分利用效率,保证小麦产量的有效方法。

Water Utilization and Matter Production in Winter Wheat under Soil-Coated Ultrathin Plastic-Film Mulching and Irrigation Management

Serious deficiency of water resource is one of the biggest problems in winter wheat production in North China Plain. We conducted a field experiment in 2010–2011 and 2011–2012 growing seasons to study the effect of soil-coated ultrathin plastic-film mulching (SCUPFM) in combination with controlled irrigation on water use efficiency and matter production of winter wheat. Compared to traditional planting practice (control), SCUPFM plus zero (rainfed) or small-amount irrigation produced wheat yield more than 7500 kg ha^-1, and consumed 2/3 to 3/4 of water. The yield-based water use efficiency of SCUPFM treatments was 24.8–26.5 kg mm^-1 ha-^1, which was 28.3–41.0% higher than that of the control. Under SCUPFM condition, the biomass-based water use efficiency in the whole growing period was 1.3–2.7 folds of the control, with an earlier peak from heading to jointing stage. Meanwhile, the harvest index also increased under SCIPFM with no or small irrigation. SCUPFM resulted in slow consumption of soil water, and 600 mm of moisture content in 2 m soil profile at seeding stage could provide enough water for the whole growing period of wheat. Water supply from 2 m soil layer was 212.2 mm in loam at Xinji site and 230.0 mm in clay at Shenzhou site. SCUPFM with irrigation or small irrigation before anthesis could significantly enhance net photosynthetic rate (P_n) and decrease transpiration rate (T_r) within 20 days after anthesis. As a result, the leaf-based water use efficiency increased significantly. However, late irrigation at mid-filling stage had no such effect. Therefore, SCUPFM in combination with no or small irrigation at proper stage is effective to maintain wheat yield and increase water use efficiency greatly in North China Plain.