近20a三峡库区(重庆段)县域尺度耕地利用碳源/汇时空演化特征

Spatio-temporal Evolution Characteristics of Carbon Source/Sink for Cultivated Land Use at County Level in the Three Gorges Reservoir Area(Chongqing Section)in Recent 20 years

耕地碳状况的研究对农业可持续发展与达成我国双碳目标具有重要意义,又可反应农业对生态影响程度。基于三峡库区(重庆段)各区县农业数据、耕地数据等,对库区各区县近20年来耕地利用碳状况的时空演变进行了研究。结果表明:(1)从时间上看,库区耕地利用碳吸收从2000年到2020年增加了818.15万t,增幅为62.68%,蔬菜和粮食作物的碳吸收比例最大;碳排放量21年间增加了8.49万t,增幅为15.23%,化肥为主要碳排放贡献者,年均碳排放比例为57.22%;库区耕地利用21年间均存在碳生态盈余,且碳足迹与单位面积碳足迹逐年递减,碳足迹减幅高达44.72%。(2)从空间上看,库区耕地利用碳排放、碳吸收在空间上均成西南高、东北低的分布格局,而碳足迹呈现出南北高、中部低的分布格局,但三者的空间差异和变化幅度差异都较大。库区耕地利用的碳汇功能总体在增强。

carbon status of cultivated land is not only of great significance for sustainable agriculture development and achieving carbon peaking and carbon neutrality goals of our country,but also reflects the degree of agricultural influence on ecology.Based on the agricultural data and cultivated land data from the districts in the Three Gorges Reservoir area(Chongqing Section),the spatio-temporal evolution of the carbon status of cultivated land utilization was studied.The results showed that:(1)From the perspective of time,the carbon absorption of cultivated land in the reservoir area increased by 8.1815 million tons from 2000 to 2020,an increase of 62.68%he carbon absorption ratio of vegetables and grain crops was the largest;In the past 21 years,carbon emissions increased by 84,900 tons,15.23%.Fertilizer was the main contributor to carbon emissions,with an average annual carbon emission ratio of 57.22%.There a carbon ecological surplus in the cultivated land utilization in the reservoir area for 21 years,and the carbon footprint and the carbon footprint per unit area continuously decreas,and the carbon footprint ecreased by 44.72%.(2)From spatial perspective the carbon emissions and carbon absorption of cultivated land utilizatin in the reservoir area were the southwest and low in the northeast,while the carbon footprint showed a pattern of high in the north and south and low in the middle,but the spatial differences and the range of change of the three were.The carbon sink function of cultivated land utilization in reservoir area generally increas.