N-Calculator与NUFER耦合模型和组合预测法在食物氮足迹研究中的应用

Application of N Calculator andNUFER coupled model as well ascombined prediction method on thestudy of food nitrogen footprint

为改善传统N-Calculator模型的局限性,加强食物氮足迹核算结果与环境影响的联系,提高活性氮管理预见性,将N-Calculator模型与食物系统养分流动(Nutrient Flows in Food Chains,Environment and Resources Use,NUFER)模型进行耦合,以估算我国2001—2020年人均食物氮足迹,建立组合预测体系。结果显示:2001—2020年,我国人均食物氮足迹由16.04 kg N/a增至18.95 kg N/a;全国食物氮足迹由20.47 Mt N/a增至26.76 Mt N/a;居民饮食结构正由以植物源食物为主的低氮消费模式转向以动物源食物为主的高氮消费模式;食物生产过程产生的活性氮的最终归宿为大气(64.3%)、水体和深层土壤(35.7%);我国食物氮足迹与人均可支配收入、城市化率、动物源食物消费氮占比呈正相关性,与恩格尔系数呈负相关性;未来10 a我国人均食物氮足迹呈增长趋势,预测结果显示年均增幅为0.16 kg N/a。

The present paper is aimed at improving the limitations of the traditional N-Calculator model,thereby strengthening the correlation between the accounting results of food nitrogen footprint and environmental impact,and improving the predictability of the management of reactive nitrogen.Accordingly,we effectively coupled the N-Calculator model with the NUFER(Nutrient flows in Food chains,Environment,and Resources use)model.Such coupled model was used to make a comprehensive analysis of the fluctuation of food nitrogen footprint in China from 2001 to 2020.At the same time,the changes in dietary structure of Chinese residents,and the correlation between food nitrogen footprint and socioeconomic factors were studied in our research.In addition,we first used the GM(1,1)model,the exponential smoothing method,and the Holt linear model to predict the trend of China's per capita food nitrogen footprint in the next decade respectively.And then,to improve the accuracy of our results,a combined prediction system for China's per capita food nitrogen footprint was established based on the theory of the optimal weighted combination model.Our results show that from 2001 to 2020,China's per capita food nitrogen footprint increased from 16.04 kg N/a to 18.95 kg N/a,while the national food nitrogen footprint increased from 20.47 Mt N/a to 26.76 Mt N/a.The dietary structure of Chinese residents has shifted from a low-nitrogen consumption pattern dominated by plant-derived food to a high-nitrogen consumption pattern dominated by animal-derived food.The amount of reactive nitrogen produced by food production increased from 15.08 Mt N/a to 20.98 Mt N/a,which finally ended up in the atmosphere(64.3%),water,and deep soil(35.7%).China's national food nitrogen footprint was positively correlated with per capita disposable income,urbanization rate,and proportion of nitrogen consumed from animal-derived food,while negatively correlated with the Engel coefficient.With the persistent change in Chinese residents'dietary structure,the problem of reactive nitrogen pollution in China will keep severe in the future.In the next decade,China's per capita food nitrogen footprint is estimated to express an increasing trend,with an average increase rate of 0.16 kg N/a.By 2030,China's per capita food nitrogen footprint will reach a high level of 20.52 kg N/a,which represents an increase of 27.9%over 2001.