Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Volcani Center, Israel.
Israel Nature and Parks Authority, Israel.
Sci Total Environ. 2022 Feb 1;806(Pt 1):150387. doi: 10.1016/j.scitotenv.2021.150387. Epub 2021 Sep 17.
Treated wastewater (TWW) is increasingly used for agricultural irrigation, and often contains higher concentrations of the major plant nutrients N, P, and K than freshwater, reducing the need for agricultural fertilization. However, excessive inputs of nutrients to cropping systems can be harmful to crops and the environment. The present study developed and employed six novel indices to assess the sustainability of TWW-irrigation and spatio-temporal trends in NPK loads to TWW-irrigated fields. Three indices relate to regional analysis of TWW-irrigation sustainability: the 'Environmental sustainability' index measures the TWW compliance with environmental irrigation standards; a 'Nutritional sustainability' index assesses whether the TWW satisfy crop fertilization requirements; a 'Basin nutrient surplus' index measures deviations of N or P loads to river basins from allowed levels. Three additional indices assess the environmental impact, potential loss of nutrients and fit of a given TWW for fertilization recommendations. We employed these indices to analyze a decade-long high spatio-temporal resolution data of TWW quality from Israel on a basin scale, for six TWW-irrigated plantation crops. The results reveal that in high-sensitivity hydrological areas, TWW is generally above the environmental standard for N and P; the TWW with lowest nutrient content is irrigated in low-sensitivity areas, leading to a reduced potential for utilization of nutrients in TWW. While the N irrigation standard (25 mg L) does not exceed the nutritional requirements of most analyzed crops, the P standard (5 mg L) results in excess fertilization for all analyzed crops. Therefore, environmental and nutritional sustainability of TWW-irrigation can be increased by diverting high-quality TWW to high-sensitivity areas and vice versa. Furthermore, development of local environmental standards will allow maximizing TWW NPK utilization in low-sensitivity areas, increasing nutritional sustainability. The indices presented in this study provide a tool to help maximize the nutritional benefits of TWW while minimizing its environmental impact.
处理后的废水（Treated wastewater，TWW）越来越多地用于农业灌溉，其所含的主要植物养分 N、P 和 K 的浓度通常高于淡水，从而减少了农业施肥的需求。然而，向种植系统中过度输入养分可能对作物和环境有害。本研究开发并采用了六个新指标来评估 TWW 灌溉的可持续性以及 TWW 灌溉农田中 NPK 负荷的时空趋势。其中三个指标与 TWW 灌溉可持续性的区域分析有关：“环境可持续性”指数衡量 TWW 是否符合环境灌溉标准；“营养可持续性”指数评估 TWW 是否满足作物施肥需求；“流域养分盈余”指数衡量流域 N 或 P 负荷与允许水平的偏差。另外三个指标评估了环境影响、潜在养分损失以及特定 TWW 施肥推荐的适配性。我们在流域尺度上，采用这些指标分析了以色列长达十年的 TWW 质量高时空分辨率数据，涉及六种 TWW 灌溉的人工林作物。结果表明，在高敏感水文区，TWW 的 N 和 P 通常高于环境标准；在低敏感区，灌溉了养分含量最低的 TWW，从而降低了 TWW 中养分的潜在利用率。尽管 N 灌溉标准（25 mg/L）未超过大多数分析作物的营养需求，但 P 标准（5 mg/L）导致所有分析作物施肥过量。因此，通过将高质量的 TWW 输送至高敏感地区并反之亦然，可以提高 TWW 灌溉的环境和营养可持续性。此外，制定当地环境标准将允许在低敏感地区最大限度地利用 TWW 的 NPK，提高营养可持续性。本研究提出的指标提供了一种工具，可以帮助在最小化环境影响的同时最大化 TWW 的营养效益。
