Data for: A hierarchical framework for unpacking the nitrogen challenge

To feed the world population while mitigating pressing nitrogen (N) pollution problems, tremendous efforts have been devoted to developing and implementing N-efficient technologies in food production, but limited progress has been made. The N management improvement on a farm does not necessarily translate to N pollution reduction on a broader scale due to complex responses of natural and human systems and lack of coordination among stakeholders. Consequently, it is imperative to develop an N management framework that encompasses the complex N dynamics across systems and spatial scales, yet simple enough to guide policies and actions of various stakeholders. Here, we propose a new framework, CAFE, that defines four N management systems (Cropping, Animal-crop, Food, and Ecosystem) in a hierarchical manner, and apply it to 13 representative countries to partition N surpluses across systems in a simple and consistent manner, thereby facilitating the identification and prioritization of syst..., Data of nitrogen contents and the classification of different crop and animal products were provided in Supplementary Data “SI_DataS1”, data of nitrogen budgets across CAFE system during the defined periods for the selected countries can be access from Supplementary Data “SI_DataS2”.,为在养活全球人口的同时缓解严峻的氮（N）污染问题，学界与产业界已在食品生产领域投入大量精力开发并推广氮高效技术，但相关进展仍十分有限。由于自然与人类系统的复杂响应机制，以及各利益相关方之间缺乏协调，农场层面的氮管理优化未必能在更大范围内实现氮污染减排。因此，亟需构建一套氮管理框架，既要能够涵盖不同系统与空间尺度下复杂的氮素动态变化，又需足够简洁以指导各类利益相关方的政策制定与实践行动。在此，我们提出一套全新的CAFE框架，以层级化方式定义了四大氮管理系统：种植系统（Cropping）、种养结合系统（Animal-crop）、食品系统（Food）以及生态系统（Ecosystem）；并将该框架应用于13个代表性国家，以简洁且统一的方式划分各系统间的氮盈余，从而助力识别各类系统并确定其优先整治顺序……不同作物与动物产品的氮含量及分类数据已在补充数据「SI_DataS1」中提供；所选国家在预设时段内CAFE系统各模块的氮收支数据，可从补充数据「SI_DataS2」中获取。