北疆地区滴灌冬小麦农田蒸散特征

于石河子大学灌溉试验站运用大型称重式蒸渗仪和小型棵间蒸发器开展滴灌冬小麦田间控水试验,设置3个灌量处理(W1=375 mm、W2=600 mm、W3=750 mm),旨在探明北疆地区滴灌冬小麦生育期农田蒸散与棵间蒸发特征。结果表明:滴灌冬小麦产量随灌量的增加呈显著增加趋势,但W2(8 450 kg·hm~(-2))与W3(8 670kg·hm~(-2))处理间差异不显著;水分利用效率以W2处理最大(1.4 kg·m~(-3)),显著高于W3和W1处理;滴灌冬小麦全生育期蒸散量随灌量增加而增加,介于412.3~707.6 mm,其中棵间蒸发量占蒸散量的27.9%~29.1%。表层土壤含水率和叶面积指数对棵间土壤蒸发影响明显,二者与棵间土壤蒸发占耗水比例均有良好的指数函数关系。深入分析表明,北疆地区滴灌冬小麦高产高效实现背景下生育期内的耗水特征为:生育期内耗水强度播种~越冬为1.0mm·d~(~(-1))、越冬~返青为0.3 mm·d~(~(-1))、返青~拔节为2.6 mm·d~(~(-1))、拔节~抽穗为6.3 mm·d~(~(-1))、抽穗~乳熟为6.6mm·d~(~(-1))、乳熟~成熟为6.2 mm·d~(~(-1))。

Evapotranspiration in a drip-irrigated winter wheat field in Northern Xinjiang

Micro-lysimeters and a large weighing lysimeter were used to measure evapotranspiration (ET) of a drip-irrigated winter wheat field at the Irrigation Experimental Station of Shihezi University. The treatments of irrigation amount (W1=375 mm, W2=600 mm, and W3=750 mm) were conducted in order to develop an efficient drip irrigation system in Xinjiang. The results showed that winter wheat yield increased significantly as the irrigation amount increased; however the difference in yield between W2 treatment (8 450 kg·hm^-2) and W3 treatment (8 670 kg·hm^-2) was not significant. W2 treatment had the highest water use efficiency (1.4 kg·m^-3) in this study, being significantly higher than that in W3 treatment and W1 treatment. Total ET increased as the irrigation amount increased. Total ET varied between 412.3 mm and 707.6 mm. Depending on the treatment and the year, soil evaporation accounted for 27.9% to 29.1% of the total ET. The water content of the surface soil and the leaf area index of the wheat crop both had significant effects on evaporation. Furthermore, both variables were exponentially related to the proportion of irrigation water that evaporated from the soil. The amounts of water consumption to obtain high winter wheat yields were as follows: seeding to overwintering, 1.0 mm·d^-1; overwintering to regreening, 0.3 mm·d^-1; regreening to jointing, 2.6 mm·d^-1; jointing to heading, 6.3 mm·d^-1; heading to milk, 6.6 mm·d^-1; and milk to maturity, 6.2 mm·d^-1