黄淮海玉米生产能源利用效率和净生态系统碳平衡时空特征

黄淮海地区是我国重要的玉米产区之一,定量化该区域玉米生产的能源利用效率和净生态系统碳平衡对提高资源利用效率和实现碳中和具有重要意义。基于国家统计数据,利用生命周期评价(LCA)、能值分析和碳平衡等方法,定量化了2004-2018年黄淮海地区(包括河北、河南、山东、安徽和江苏5个省)玉米生产的能源利用效率和净生态系统碳平衡,并阐明其时空变化特征。结果表明:黄淮海地区玉米生产的平均能源利用效率、温室气体排放量、净生态系统碳平衡和可持续性指数分别为3.9、3.8 t CO₂-eq/hm²、12.6 t C/hm²和6.8。不同年份间黄淮海地区玉米生产的能源利用效率和净生态系统碳平衡存在显著差异,能源利用效率在2012年最高,为4.3,在2005和2007年最低,为3.7;净生态系统碳平衡在2015年最高,为14.2 t C/hm²,在2005年最低,为10.1 t C/hm²。各省份中以河北省玉米生产的能源利用效率、净生态系统碳平衡和可持续性指数最高,分别高于区域平均15.3%、9.6%和26.4%,较最低的江苏省高45.5%、22.0%和88.8%。河北省、河南省和山东省的综合得分均为正值,具有较高的资源利用效率和生态环境效益。黄淮海地区玉米生产资源投入、能源利用效率、生态环境效益和净生态系统碳平衡在时空尺度上存在较大的差异,应制定区域特异性优化管理策略,减少化肥和农药的施用,施用增效肥料和高效生物农药等,采用秸秆还田等保护性耕作措施,积极推进规模化和机械化的发展,实现黄淮海地区玉米生产的绿色可持续发展。

Spatio-temporal characteristics of energy use efficiency and net ecosystem carbon budget of maize production in Huang-Huai-Hai region

The Huang-Huai-Hai region is one of the most important main producing areas for maize production in China. Quantifying the energy use efficiency and net ecosystem carbon budget of maize production in this area is of great significance for improving resource use efficiency and achieving carbon neutrality. Based on the national statistical panel data, the energy use efficiency and net ecosystem carbon budget of maize production in Huang-Huai-Hai region (including Hebei Province, Henan Province, Shandong Province, Anhui Province, and Jiangsu province) were quantified, and their spatial and temporal variation characteristics were clarified by integrated using the methods of life cycle assessment, energy analysis, and carbon balance analysis. The results showed that the mean energy use efficiency, greenhouse gas emissions, net ecosystem carbon budget, and carbon based sustainability index of maize production in Huang-Huai-Hai area were 3.9, 3.8 t CO₂-eq/hm², 12.6 t C/hm², and 6.8, respectively. There were significant differences in the energy use efficiency and net ecosystem carbon budget of maize production in the Huang-Huai-Hai region among years. The energy use efficiency was highest in 2012 which was 4.3 and that in 2005 and 2007 was lowest, which were both at 3.7. The net ecosystem carbon budget was highest in 2015 which was 14.2 t C/hm², while that in 2005 was lowest which at 10.1 t C/hm². The energy use efficiency, net ecosystem carbon budget, and carbon based sustainability index of maize production in Hebei Province were the highest, which were higher than the regional average of 15.3%, 9.6%, and 26.4%, respectively, and 45.5%, 22.0% and 88.8% higher than that in Jiangsu Province, respectively. The comprehensive scores considering above mentioned indicators for maize production of Hebei Province, Henan Province and Shandong Province were all positive. The three provinces (Hebei Province, Henan Province and Shandong Province) had high resource use efficiency, ecological and environmental benefits. Resource inputs, energy use efficiency, ecological and environmental benefits, and net ecosystem carbon budget of maize production in Huang-Huai-Hai region were different on the spatial and temporal scales. Regionally specific optimization management strategies should be formulated to reduce the application of chemical fertilizers and pesticides, for instance, using enhanced efficiency fertilizers (e.g., controlled release fertilizers) and applying high use efficiency biological pesticides, etc. Conservation tillage measures such as straw returning should be adopted actively to promote the development of scalable and mechanized maize production, and realize the sustainable development of maize production in the main producing area of maize in China.