不同水分管理下全田土下微膜覆盖的冬小麦耗水特性

Water Consumption Characteristics of Winter Wheat with Soil-Coated Ultrathin Plastic-Film Mulching Under Different Water Managements

【目的】针对海河平原水资源匮乏与冬小麦生产水分高耗的现实矛盾,研究不同水分管理条件下全田土下微膜覆盖的冬小麦耗水特性,探索区域小麦节水生产新方法。【方法】采用大田试验,以小麦常规种植方法为对照,进行两地3年试验研究。【结果】全田土下微膜覆盖下,小麦生育期田间耗水量显著降低116.1—167.9 mm,土壤贮水消耗占总耗水的55.5%—77.9%。覆膜显著减少了小麦返青前的耗水量,生育后期耗水占总耗水量的比例提高。覆膜条件下,拔节前根系吸水深度较露地处理浅40 cm,生育期2 m土体可供水212.2—240.3 mm,春季灌水75 mm小麦对土壤贮水消耗集中在0—140 cm土层,比常规生产(CK,3次灌水共225 mm)深40 cm,灌水时间后移可显著减少2 m土体贮水消耗。土下微膜覆盖条件下,雨养耗水284.3 mm可获得不低于7 500 kg·hm-2的小麦产量,播前灌水≥60 mm或抽穗期灌水75 mm,可获得与CK相当的产量,水分利用效率比CK提高40%以上、净水分利用效率和灌溉水利用效率达到最高。【结论】全田土下微膜覆盖雨养或适时少量灌水是海河平原大幅降低小麦耗水,缓解水资源供需刚性矛盾的一种新型种植方法。

[Objective] In the light of the actual conflict between severe deficiency of water resource and more water consumption of winter wheat production in Haihe Plain, a field experiment was conducted to study the water consumption characteristics of winter wheat planted with soil-coated ultrathin plastic film mulched under different water managements, and the objective of this study was to search out a new water saving method for winter wheat production. [Method] The test lasted for three winter wheat growing years in two sites, and a field experiment was adopted with a conventional wheat planting method as a control. [Result] Under soil-coated ultrathin plastic film mulching, the field water consumption of winter wheat was significantly decreased by 116.1-167.9 mm in a whole growing season, and the soil water consumption accounted for 55.5%-77.9% of the total. With plastic film mulching, the water consumption before wheat recovery was reduced significantly so that the water consumption percentage from jointing to harvest was increased. Under soil-coated plastic film mulching condition, the water intake depth in soil body was 40 cm shallower than that under bare field, the 2 m-deep soil layer could supply 212.2-240.3 mm water for wheat in the whole growing season. As one-time 75 mm irrigation in spring was practised, the winter wheat uptook the water from 0-140 cm soil layer, which was 40 cm deeper than the control that was irrigated with the total 225 mm water for three times, soil water consumption was decreased significantly in 2 m-deep layer as the one-time 75 mm irrigation delayed. Under soil-coated ultrathin plastic film mulching condition, the rain-fed wheat after sowing achieved a yield more than 7 500 kg.hm2 with a 284.3 mm filed water consumption, the wheat irrigated with over 60 mm water before sowing or 75 mm water at heading stage could achieve an equivalent yield to the control, and the water use efficiency was increased by more than 40% compared with the control, the net water use efficiency and irrigation water use efficiency were the best among all the treatments. [Conclusion] Soil-coated plastic film mulching and rain fed or with little irrigation timely is a new way for winter wheat production as it can considerably decrease water consumption and relieve the intense conflict between water resource supply and requirement in Haihe Plain.