全球灌区面临着控制硝酸盐投入和确保粮食安全生产的矛盾挑战。防治灌区硝酸盐污染,以中国黄河流域(宁夏段)为例,采用氮和氧双同位素示踪和广泛的现场调查来分析来源,命运,农业排水沟硝酸盐含量及其影响因素。硝酸盐源示踪结果表明,沟渠中进入黄河的硝酸盐源的年比例如下:粪便和污水,肥料,和自然来源,比率为33%,35%,整体32%。硝酸盐命运的结果表明,与铵肥相比,硝酸盐肥料中的硝酸盐在排水沟(生态沟)中的残留率较低,可以在一年内进行自我生态恢复。影响因素研究结果表明,作物对水分和养分的需求较高,比如蔬菜,“剥削性种植”造成的硝酸盐污染和环境危害是旱地和稻田正常种植做法的五倍,特别是没有作物拦截的冬季灌溉会加剧土壤中硝酸盐的浸出。因此,灌区硝酸盐管理应侧重于预防和控制冬季灌溉期间的“剥削性种植”和损失,同时适当调整氮铵肥的施用量。研究结果可指导缓解畜牧业等灌区硝酸盐污染的策略,施肥,灌溉管理,沟渠优化,和作物种植。
Global irrigation areas face the contradictory challenges of controlling nitrate inputs and ensuring food-safe production. To prevent and control nitrate pollution in irrigation areas, the study using the Yellow River basin (Ningxia section) of China as a case study, employed nitrogen and oxygen dual isotope tracing and extensive field investigations to analyze the sources, fate, and influencing factors of nitrate in agricultural drainage ditches. The results of source tracing of nitrate showed that annual proportions of nitrate sources entering the Yellow River in the ditches are as follows: for manure & sewage, fertilizer, and natural sources, the ratios are 33%, 35%, and 32% overall. The results of nitrate fate showed that
nitrates derived from nitrate fertilizer exhibit a lower residual rate in drainage ditches (ecological ditches) compared to ammonium fertilizer, which can undergo self-ecological restoration within one year. The results of influencing factors showed that crops with high water and nutrient requirements, such as vegetables, the nitrate pollution and environmental harm resulting from \"exploitative cultivation\" are five times more than normal cultivation practices in dryland and paddy fields, especially winter irrigation without crop interception exacerbates the leaching of nitrate from the soil. Therefore, nitrate management in irrigation areas should focus on preventing and controlling \"exploitative cultivation\" and losses during winter irrigation, while appropriately adjusting the application ratio of ammonium nitrogen fertilizers. The results of the study can guide strategies to mitigate nitrate pollution in irrigated areas such as livestock farming, fertilizer application, irrigation management, ditch optimization, and crop cultivation.