中国农村居民生活氮素流动特征

人类生活消费是陆地生态系统氮素流动的主要驱动力。定量核算和评估农村居民生活消费氮产生(N_RUR)及其活性氮(Nr)排放特征，对农村氮的可持续管理和生态环境改善具有重要的指导意义。以中国为例(2000—2020年),建立了N_RUR的产生及其活性氮排放核算框架。结果表明：20年来N_RUR上升了36.7%,年均5.62 Tg/a,食物消费氮是最大的贡献源(43.2%),工业日用品和家庭生活燃料消费氮分别占31.5%和25.3%;Nr排放量占N_RUR的25.4%(年均1.43 Tg/a),其以年均1.3%速率下降；NH₃挥发是最大的Nr排放源(50.1%),其次为排入地表水的Nr(31.0%)、NO_x(15.8%)和N₂O(2.0%),排入地下水的Nr仅占1.1%。加大人类粪尿排泄物的处置能力，减少秸秆燃料的使用比例、优化农村居民生活能源消费结构对农村居民生活消费Nr减排至关重要。

Nitrogen flow characteristics of living consumption of rural residents in China

Human consumption is the main driving force of nitrogen (N) flow in terrestrial ecosystems. Quantitative calculation and evaluation of N flow of rural residents'' living consumption (N_RUR) and its reactive nitrogen (Nr) characteristics have practical and guiding significance for sustainable N management and the improvement of ecological environment of rural area. Here, a framework was developed to evaluate the generation of N_RUR, and associated its Nr emissions in China rural from 2000-2020. The results showed that the N_RUR increased by 36.7% in the past 20 years, with an annual average of 5.62 Tg/a. Food consumption N was the largest contributor (43.2%), and industrial daily necessities and domestic fuel consumption accounted for 31.5% and 25.3% of N_RUR, respectively. The Nr emission accounted for 25.4% of N_RUR (1.43 Tg/a), which decreased at an averagely annual rate of 1.3%. NH₃ volatilization was the largest emission source (accounting for 50.1% of the total Nr emissions), followed by the amount of Nr discharged into surface water (31.0%), NO_x (15.8%), N₂O (2.0%), and the amount of Nr lost into groundwater accounted for only 1.1%. Increasing the disposal capacity of human excrement, reducing the use proportion of straw fuel and optimizing the domestic energy consumption structure of rural residents are crucial to the reduction of Nr emissions from rural residents'' living consumption. The study provides a scientific basis for the management and prevention of Nr from rural residents'' living consumption, so as to reduce its impact on the ecological environment and formulate more sustainable policies for China and other developing countries.