15N同位素在华北冬小麦夏玉米氮营养来源研究中的应用

小麦-玉米一年两作是华北平原最主要的种植方式之一，对保障国家粮食安全至关重要。阐明该种植体系作物氮营养来源定量组成对区域养分资源管理、施肥制度优化、作物营养状况调控都具有十分重要的意义。¹⁵N作为氮元素的一种稳定同位素，其示踪技术在农田氮肥去向，作物氮营养来源等农业生产领域得到广泛应用。本文主要概述了¹⁵N同位素技术在研究当季施入化肥氮、前茬残留化肥氮、播前土壤固有硝态氮对华北冬小麦-夏玉米氮营养贡献中的具体应用方法、实例及相关研究结果，并对叶面肥氮、还田秸秆氮、大气沉降氮等其他氮营养来源的研究进行了展望，以期为该种植体系养分资源管理以及施肥制度优化提供理论参考。

Application of15N Isotope for the Identification of Nitrogen Nutrition Sources of Winter Wheat and Summer Maize in North China Plain

Winter wheat-summer maize rotation planting, with two harvests per year, is the main cropping system in the North China Plain (NCP), and plays an important role in ensuring national food security. Clarifying quantitatively the crop nitrogen nutrient source in the system is of great significance to the efficient management of nutrient resources, the optimization of fertilization system and the reasonable regulation of crop nutrition status. As the stable isotope of nitrogen,¹⁵N has been widely used in the field of agricultural production, such as the fates of nitrogen fertilizer applied to soil, the sources of crop nitrogen nutrition, and so on. The objective of this study was to summarize nitrogen nutrition contributions of chemical fertilizer-N applied in-season, residual fertilizer-N applied in the previous season, and soil inherent nitrate-N prior to sowing to winter wheat and summer maize in NCP using¹⁵N isotope tracing technology. Meanwhile, some case studies and related research results were also introduced. Moreover, we put forward the prospect on the study on other nitrogen nutrient sources, such as foliar fertilizer nitrogen, nitrogen in straw returning to the field, atmospheric dry and wet deposition nitrogen etc. The study aimed to provide theoretical reference for optimizing nitrogen nutrient resource management and fertilizer-N application schedule in the wheat-maize double cropping system in NCP.