中国耕地利用净碳汇时空演进及综合分区

Spatiotemporal evolution and comprehensive zoning of net carbon sink in cultivated land use in China

耕地利用净碳汇是影响耕地利用进程的重要因素,分区优化耕地利用是实现中国农业绿色、可持续发展的有效手段。基于耕地利用碳源-碳汇视角测算了2005—2020年中国31省(市、区)耕地利用净碳汇量,利用核密度估计分析其动态演进趋势,并探究耕地利用净碳排放与农业经济的脱钩效应;结合脱钩结果和粮食产区进行综合分区优化,借助灰色模型预测了2021—2035年各综合分区的净碳汇量及脱钩状态。结果表明:1)研究期内耕地利用净碳汇量呈波动式上升,年均增速3.740%,粮食主产区碳汇能力优于其他粮食产区;2)核密度估计显示,中国耕地利用净碳汇地区差距逐渐缩小,但仍存在区域发展不均衡,粮食主产区、产销平衡区和主销区均呈向碳汇高值区的扩散态势;3)研究期内耕地利用净碳排放与农业经济脱钩状态主要为强脱钩,2020年除北京、上海、广东和海南外,其他省(市、区)均处于实现经济效益和生态效益协调的综合分区;4)预测2021—2035年中国耕地利用碳汇能力保持平稳增长,各综合分区脱钩状态主要为强脱钩。并对全国及各综合分区提出针对性优化策略,推进实现耕地利用低碳、绿色、高质量发展。

Net carbon sink from land-use change has been one of the most important factors on the process of cultivated land use.The comprehensive zoning optimization of cultivated land use can be an effective way to realize the green and sustainable development of agriculture and improve the net carbon sink level of cultivated land use in China.A theoretical basis can also be provided for the protection of cultivated land at the national level,and the optimal allocation of cultivated land resources.In this study,the trend of net carbon sink of cultivated land use was estimated in 31 Provinces(cities and districts)in China from 2005 to 2020,particularly from the perspective of carbon source and carbon sink of cultivated land use.The dynamic evolution and interval difference were analyzed using Kernel density estimation.The decoupling effect was also established between the net carbon emission of cultivated land and agricultural economy.After that,the comprehensive zoning of cultivated land use was optimized to combine with the decoupling and characteristics in the main grain producing areas.A Grey Model(GM)was utilized to predict the change trend and decoupling status of net carbon sink in each comprehensive zoning from 2021 to 2035.The results showed that:1)There was a fluctuating upward trend for the net carbon sink of cultivated land use,with an average annual growth rate of 3.740%in the study period.The spatial difference of carbon sink capacity was much better in the main grain producing areas,compared with the rest.2)Kernel density estimation shows that the regional gap of net carbon sink of cultivated land use was gradually narrowing.However,there was still a regional imbalance.The main grain producing areas,the balance of production and marketing areas,and the main sales areas all showed a trend of diffusion to the high-value carbon sink areas.3)There was the mainly strong decoupling between the net carbon emissions from the cultivated land use and agricultural economy in the study period.A comprehensive zone was achieved for the coordination of economic and ecological benefits in the most provinces(cities and districts),except for Beijing,Shanghai,Guangdong and Hainan in 2020.4)The GM predicted that the carbon sink capacity of cultivated land use would maintain a steady growth from 2021 to 2035,and there was the strong decoupling status of each comprehensive zone.Consequently,it is very feasible for the unification of economic and ecological benefits in the future cultivated land use.The finding can also provide a strong reference and guidance for the“double carbon”goal in the field of cultivated land.Finally,the targeted optimization strategies and directions can be greatly contribute to the coordinated development of economic and ecological benefits of cultivated land use in the whole country and various comprehensive divisions,in order to achieve low-carbon,green,and high-quality development of cultivated land use.