State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering, Hohai University, Nanjing, Jiangsu 210098, China; College of Water Conservancy and Hydropower, Hohai University, Nanjing 210098, China; Key Laboratory of Efficient Irrigation-Drainage and Agricultural Soil-Water Environment in Southern China of Ministry of Education, Hohai University, Nanjing, Jiangsu 210098, China.
College of Water Conservancy and Hydropower, Hohai University, Nanjing 210098, China; Key Laboratory of Efficient Irrigation-Drainage and Agricultural Soil-Water Environment in Southern China of Ministry of Education, Hohai University, Nanjing, Jiangsu 210098, China; Lianshui Water Conservancy Research Station, Huai'an 223200, China.
Sci Total Environ. 2018 Jan 1;610-611:84-93. doi: 10.1016/j.scitotenv.2017.08.011. Epub 2017 Aug 10.
Water footprint (WF) is a comprehensive measure of water consumption by human activities and can be used to assess the impact on both water volume and quality. This study aims to explore the feasibility of evaluating green, blue and grey WFs of crop production based on field measurements. The irrigated paddy rice grown in three different experimental sites in different typical irrigation districts in Huai'an, East China over 2011 to 2014 was taken as study case. With fixed irrigation and fertilization, on the basis of measuring field water and fertilizer balance at daily step, we calculated WF of crop production under different test treatments. Results show that crop water requirement of rice was measured as 667.1mm and 6.2% of the total nitrogen (T-N) was washed away from farmland accompany with drainage and percolation. Average annual WF of paddy rice during 2011-2014 in Huai'an was 1.760m/kg (33.3% green, 25.8% blue and 40.9% grey). The level of WF and blue water proportion in different locations (irrigation districts) and different years changed slightly, while the proportion of green and grey WF changed with the variance of precipitation. Green water proportion was 25.1%, 34.2 and 44.2%, while 48.0%, 40.2% and 31.0% for grey water proportion under precipitation levels of 400, 600 and 800mm, respectively. The reduced grey WF was due to increased drainage. This study not only proved the feasibility of assessing WF of crop production with field experiments, but also provided a new method for WF calculation based on field water and fertilizer migration processes.
水足迹（WF）是衡量人类活动对水资源消耗的综合指标，可用于评估水量和水质两方面的影响。本研究旨在探索基于田间实测评估作物生产的绿水、蓝水和灰水足迹的可行性。以 2011 年至 2014 年在江苏省淮安市三个不同典型灌区的 3 个不同田间试验点种植的水稻为研究对象，在固定灌溉施肥条件下，逐日监测农田水量和肥料平衡，计算不同试验处理下的作物生产水足迹。结果表明，水稻的作物需水量为 667.1mm，农田排水和渗漏损失的总氮（T-N）量占总氮投入量的 6.2%。2011-2014 年，淮安市水稻平均年水足迹为 1.760m/kg（绿水 33.3%、蓝水 25.8%、灰水 40.9%）。不同地点（灌区）和不同年份的水足迹和蓝水比例水平变化较小，而绿水和灰水足迹的比例随降水的变化而变化。当降水量分别为 400、600 和 800mm 时，绿水比例分别为 25.1%、34.2%和 44.2%，灰水比例分别为 48.0%、40.2%和 31.0%。灰水足迹减少是因为排水量增加。本研究不仅证明了基于田间试验评估作物生产水足迹的可行性，而且为基于田间水和肥料迁移过程的水足迹计算提供了新方法。
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