灌溉措施对稻田灰水足迹和水分利用效率的影响研究

Effect of Irrigation on Footprint of Grey Water and Water Use Efficiency of Paddy Fields

[目的]揭示稻田水资源利用效用,优选高效灌排模式。[方法]通过观测浅水勤灌(FSI)、浅湿灌溉(WSI)、控制灌溉(COI)和蓄水控灌(RCI)下稻田水肥迁移过程,结合水足迹与用水效率指标,分析了灌溉措施对稻田排水、灰水足迹及其水分利用效率的影响。[结果]受不同灌溉措施的影响,稻田排水量、灰水足迹及其水分利用效率均存在差异。2017—2018年各处理稻田排水量为387.6~593.7 mm,RCI处理最小,而COI处理最多。FSI、WSI、COI、RCI处理下水稻灰水足迹的年均值分别为386.3、420.6、431.2、273.1 mm。蓝水足迹、绿水足迹、灰水足迹的组成比例分别为6.0%~24.0%、31.8%~58.0%、37.0%~54.0%,且RCI处理下绿水足迹最大、蓝水足迹和灰水足迹均最小,其用水结构更符合水稻节水减污的要求。[结论]对比传统方法和水足迹框架下农业水资源评价指标,将田间排水量及灰水足迹加入稻田水分利用效率评价至关重要,且蓄水控灌为综合灰水足迹和水分利用效率下的高效灌溉措施。

[Objective] Improving irrigation water use efficiency is important in developing sustainable agriculture.Taking paddy field as an example,this paper investigates how to achieve this goal via irrigation optimization.[Method] The study is based on changes in water and fertilizers measured in 2017—2018 from fields under four different irrigation methods:frequent-shallow irrigation(FSI),wet-shallow irrigation(WSI),controlled irrigation(COI),rain-catching and controlled irrigation(RCI).For each irrigation,we calculate its impact on drainage,grey water footprint(GWF),and water use efficiency combined with grey water footprint(WF).[Result] Drainage from different treatment ranged from 387.6 to 593.7 mm,with RCI and COI draining the least and highest water,respectively.The annual average GWF of FSI,WSI,COI and RCI is 386.3,420.6,431.2 and 273.1 mm,respectively.The percentage of blue,green,and gray water in all treatments is in the range of 6.0%~24.0%,31.8%~58.0%,37.0%~54.0%,respectively,with the RCI giving the greatest green footprint and least blue print.[Conclusion]Comparing traditional method and the proposed WF framework reveals that it is crucial to considering both drainage and GWF in evaluating water use efficiency of the paddy fields.For the four irrigation methods we compare,RCI is most efficient for paddy fields in the region we studied.