College of Resources and Environment, Southwest University, Tiansheng Road 02, Chongqing 400715, China.
Water Systems and Global Change Group, Wageningen University & Research, Droevendaalsesteeg 3, 6708 PB Wageningen, The Netherlands.
Environ Sci Technol. 2020 Oct 6;54(19):11929-11939. doi: 10.1021/acs.est.0c01333. Epub 2020 Sep 11.
Agriculture contributes considerably to nitrogen (N) inputs to the world's rivers. In this study, we aim to improve our understanding of the contribution of different crops to N inputs to rivers. To this end, we developed a new model system by linking the MARINA 2.0 (Model to Assess River Input of Nutrient to seAs) and WOFOST (WOrld FOod STudy) models. We applied this linked model system to the Yangtze as an illustrative example. The N inputs to crops in the Yangtze River basin showed large spatial variability. Our results indicate that approximately 6,000 Gg of N entered all rivers of the Yangtze basin from crop production as dissolved inorganic N (DIN) in 2012. Half of this amount is from the production of single rice, wheat, and vegetables, where synthetic fertilizers were largely applied. In general, animal manure contributes 12% to total DIN inputs to rivers. Three-quarters of manure-related DIN in rivers are from vegetable, fruit, and potato production. The contributions of crops to river pollution differ among sub-basins. For example, potato is an important source of DIN in rivers of some upstream sub-basins. Our results may help to prioritize the dominant crop sources for management to mitigate N pollution in the future.
农业对世界河流的氮（N）输入有很大贡献。在本研究中，我们旨在通过将 MARINA 2.0（评估河流向海洋输入养分的模型）和 WOFOST（世界粮食研究）模型联系起来，来提高我们对不同作物对河流 N 输入贡献的认识。为此，我们开发了一个新的模型系统，并将其应用于长江作为一个说明性的例子。长江流域作物的 N 输入具有很大的空间变异性。我们的研究结果表明，2012 年，约有 6000 吉克的 N 以溶解无机氮（DIN）的形式从作物生产进入长江所有河流。其中一半来自水稻、小麦和蔬菜的单一种植，这些作物大量施用了合成肥料。一般来说，动物粪便对河流 DIN 输入总量的贡献为 12%。与粪便相关的 DIN 有四分之三来自蔬菜、水果和土豆生产。作物对河流污染的贡献因子流域而异。例如，在一些上游子流域的河流中，土豆是 DIN 的一个重要来源。我们的研究结果可能有助于确定未来管理中需要优先考虑的主要作物源，以减轻 N 污染。
