湖北省作物系统氮素利用及其环境影响综合评估

Comprehensive Assessment of Nitrogen Utilization of Multi-crop System and Its Environmental Impacts in Hubei Province

粮食安全、资源高效和环境友好是发展可持续农业的核心问题。湖北省作为长江中下游平原重要农业省份,亟需综合评估作物系统氮素利用及其环境影响。针对湖北省主要粮食作物(水稻、小麦、玉米、大豆)和经济作物(茶叶、水果、蔬菜),提出作物系统氮素利用效率及其环境影响的综合评估框架,系统分析2020年湖北省作物生产过程中氮素利用状况及环境效应的空间分异特征。结果表明,在氮素利用方面,湖北省农作物施氮量、氮盈余和温室气体排放强度偏高,氮肥偏生产力和氮素利用率较低。湖北省施氮量比同年中国施氮量平均水平高43%;粮食作物氮素利用率为35.17%,而经济作物氮素利用率仅为9.99%,存在较大增效空间。在环境影响方面,经济作物氮盈余总量(43.36%)低于粮食作物(56.64%),其中水稻氮盈余总量(38.27%)最高;然而,粮食作物产生的温室气体在环境影响中占主导地位。从空间分布上看,湖北省施氮量呈现中部高、东西低的趋势。经济作物温室气体排放主要集中在鄂南和鄂北地区,粮食作物温室气体排放主要集中在鄂西和鄂东地区。经济作物氨气单位面积挥发量比粮食作物大,呈现南北高、东西低的分布格局。研究可为后续降低湖北省氮肥投入、提高氮素利用率和缓解温室气体排放提供有益参考,建议管理措施调整和政策支持齐进,针对不同区域现状进行种植结构调整与施氮优化,助力湖北省资源利用效率提升。

Food security,high use-efficiency of resources,and friendly environment are the central concerns of sustainable agricultural development in China.Hubei Province,as a significant agricultural region in the middle and lower reaches of the Yangtze River,requires a comprehensive assessment of nitrogen(N)utilization and its environmental impacts in the multi-crop system.We focused on the major cereal crops including rice,wheat,maize,and soybeans as well as cash crops including tea,fruits,and vegetables,and proposed a comprehensive assessment framework to evaluate the N utilization efficiency and its environmental impacts in multi-crop system of Hubei Province in the year of 2020.The results show that there were high N application rates,N surplus,and greenhouse gas(GHG)emissions,but low N use efficiency and partial fertilizer productivity in Hubei Province.The N application rate in Hubei Province was higher than the national average by 43%.The N use efficiency for grain crops was 35.17%,while that for cash crops was only 9.99%.For environmental impacts,the total N surplus in cash crops(43.36%)was lower than that in grain crops(56.64%),the highest nitrogen surplus was from rice(38.27%).However,grain crops contributed higher GHG emissions than cash crops.N application rates in Hubei Province demonstrated a pattern with higher values in central area but lower values in the east and west regions.GHG emissions from cash crops were predominantly concentrated in the southern and northern regions of Hubei,while those from grain crops were concentrated in the western and eastern areas.Ammonia emissions per unit area from cash crops were significantly higher than from grain crops,exhibiting a distribution pattern with higher values in the north and south but lower values in the east and west.This research provides a valuable evaluation framework to enhance N use efficiency and reduce N fertilizer inputs and GHG emissions in the multi-crop system.It is recommended that implementing coordinated management measures and related policies,adjusting planting structures,and optimizing nitrogen application based on the specific characteristics of different regions could contribute to improve N utilization efficiency in Hubei Province.