华中农业大学讯（通讯员 雷鸣） 近日，我校水土流失过程与生态调控创新团队在流域面源污染状况及管理方面取得进展，并在Water Research发表了题为“Rainstorms peak governs nitrate export pathways and patterns: Insights from high-frequency sampling and stable isotopes”的学术论文。
氮肥过量施用引起的硝酸盐污染，是威胁全球水体安全的突出难题。在降雨集中、地形复杂的亚热带农业流域，暴雨更是成为氮素向水体迁移的“加速器”。然而，暴雨并非千篇一律——雨强峰值出现的时间早晚，是否会改变硝酸盐的“出行路线”，从而影响水质？这一问题长期缺乏系统解答。为此，该团队选择南水北调中线核心水源地——丹江口库区的五龙池流域，开展了野外高频监测研究。通过捕捉20场典型暴雨事件，团队创新性地依据雨强峰值出现位置，将暴雨事件划分为“早峰型”“中峰型”和“晚峰型”三类，并结合稳定同位素示踪技术与贝叶斯混合模型，精准解析了不同雨型下硝酸盐的输出路径与迁移模式。研究发现：I. 早峰型暴雨（雨强峰值提前）中，硝酸盐主要随雨水和浅层土壤水快速输出，呈现“稀释”与“稳定”输出的混合模式，硝酸盐浓度高、变化幅度大；II. 中峰型暴雨（雨强峰值居中）则主要激活中、深层土壤水，硝酸盐输出呈现显著的“稳定”输出行为，导致流域出口硝酸盐浓度最高；III. 晚峰型暴雨（雨强峰值靠后）中，各层土壤水贡献相对均衡，硝酸盐输出以“稀释”行为为主导，硝酸盐浓度最低。
该研究不仅深化了对暴雨—径流—水质耦合过程的理解，更有助于流域差异化治理策略的制定。例如，在早峰型暴雨事件多发区域，应强化生态沟渠、湿地拦截等面向地表径流的治理工程；而在晚峰型暴雨主导区，则需关注深层含水层中遗留氮的释放风险。
不同暴雨雨型下流域最佳管理措施概念图
我校博士研究生雷鸣、硕士研究生师泳泳为论文的共同第一作者，王剑副教授和史志华教授为论文通讯作者。我校硕士研究生黄一鸣、硕士研究生王磊、博士研究生李肖、肖海兵副教授，长江水利委员会长江流域水土保持监测中心姚赫、顾朝军，长江水利委员会长江水资源保护科学研究所徐建峰、王超，丹江口市水利和湖泊局姜海、李海燕参与了研究。本研究得到了国家自然科学基金项目（批准号：42577384、U22A20611）的资助。
英文摘要：Rainstorm events can flush large amounts of nitrate from agricultural lands into aquatic environments, posing significant threats to drinking water quality and ecosystem health. However, how intra-event rainstorm structure governed hydrological responses and nitrate transport remain poorly understood. Here, we conducted high-frequency monitoring and sampling to determine nitrate export pathways and patterns during 20 rainstorm events. Intra-event rainstorm regime was classified as early-, center-, and late-peak regimes based on the co-occurrence position of the fluctuation index of rainstorm peak and the maximum 30 min rainstorm intensity. Stable water isotopes technique was used to partition nitrate export pathways (soil water, groundwater, rainwater), concentration-discharge relationships further revealed nitrate export patterns under different rainstorm regimes. The results indicated that rainwater (16.7%) and shallow soil water (21.6%) served as the primary pathway of nitrate export for early-peak rainstorm events, with comparable contributions from dilution (46%) and chemostatic behavior (36%). In center-peak rainstorm events, deep soil water was the dominant export pathway of nitrate (42.1%), with chemostatic behavior dominating (75%) and resulting in the highest nitrate concentrations (4.97 mg L-1). In contrast, late-peak rainstorm exhibited comparable contributions from different soil layers, promoting dilution behavior (60%), corresponding to lower nitrate concentrations (3.00 mg L-1). These results indicate that the intra-event rainstorm structure can alter nitrate export pathways and patterns, involving more complex activation patterns of hydrological pathways than previously recognized. Understanding these dynamics provides a scientific foundation for developing watershed management strategies aimed at controlling nitrate pollution in aquatic ecosystems.
原文链接：https://doi.org/10.1016/j.watres.2026.125405
审核人：史志华
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