College of Agricultural Science and Engineering, Hohai University, Nanjing, 210098, China; Key Laboratory of Efficient Irrigation-Drainage and Agricultural Soil-Water Environment, Ministry of Education, Hohai University, Nanjing, 210098, China.
College of Agricultural Science and Engineering, Hohai University, Nanjing, 210098, China.
J Environ Manage. 2022 Jan 15;302(Pt B):114116. doi: 10.1016/j.jenvman.2021.114116. Epub 2021 Nov 15.
Water footprint (WF) quantifies the impact of paddy field evapotranspiration (ET) and non-point source pollution on water resources and is an evaluation index for water sustainability. However, it is difficult to measure accurately using the existing method, which is based on parameter assumption without considering the field water conditions. In this study, a generic and physically based method for blue, green, and grey water accounting in paddy rice cultivation is introduced. We conducted field experiments using the common flood irrigation (CFI) and water-saving irrigation (SWI) modes in Nanjing, East China. By tracing the sources of ET and the migration process of multiple pollutants (TN, TP, NH-N, and NO-N), the characteristics of blue-green water consumption and the actual amount of water required to dilute pollutants at different growth stages of rice under CFI and SWI were analyzed. The WF of paddy rice was 1000 m/t (49% WF, 17% WF, 34% WF) and 910 m/t (50% WF, 10% WF, 40% WF) for CFI and SWI, respectively. The WF for paddy rice production was reduced by approximately 9% under SWI compared to CFI, with declines of 47% for WF and 8% for WF. The SWI mode changed the ratio of blue to green water fluxes in field water by reducing irrigation during non-critical periods, and green water was used preferentially to enhance its utility. This conceptual method is the first to describe the formation mechanism of blue, green, and grey WFs in paddy systems. It can be extended to different scales and agro-ecosystems that show the influence of crop cultivation on water resources.
水足迹（WF）量化了稻田蒸散（ET）和非点源污染对水资源的影响，是水可持续性的评价指标。然而，现有的方法基于参数假设，没有考虑田间水分条件，因此难以准确测量。本研究介绍了一种通用的基于物理的稻田蓝、绿、灰水核算方法。我们在中国东部南京进行了常规淹灌（CFI）和节水灌溉（SWI）模式的田间试验。通过追踪 ET 的来源和多种污染物（TN、TP、NH-N 和 NO-N）的迁移过程，分析了 CFI 和 SWI 下不同水稻生长阶段蓝绿水资源消耗的特征和实际稀释污染物所需的水量。CFI 和 SWI 下水稻的 WF 分别为 1000m/t（49% WF、17% WF、34% WF）和 910m/t（50% WF、10% WF、40% WF）。与 CFI 相比，SWI 下水稻生产的 WF 减少了约 9%，WF 减少了 47%，WF 减少了 8%。SWI 模式通过减少非关键期的灌溉，改变了田间水的蓝绿水流比率，优先利用绿水以提高其利用率。这种概念方法是首次描述稻田系统中蓝、绿、灰 WF 的形成机制。它可以扩展到不同的规模和农业生态系统，以展示作物种植对水资源的影响。
