近24年三峡水库库尾重庆市江津区耕地利用碳汇及碳足迹变化

目的 碳排放增长引发的全球气候变暖等问题日益受到社会各界的关注，耕地作为碳源和碳汇双重作用载体，剖析其碳排放演进特征显得极为重要。方法 文章基于1997—2020年重庆市江津区耕地利用变更数据和农业数据等，对农作物生育过程中碳吸收及生产过程中的碳排放做了分类测算。结果 （1）江津区耕地利用碳排放、碳吸收、碳汇均成增长趋势，与1997年相比，碳排放增加了3.46万t，涨幅高达86.86%，碳排放强度涨幅为91.18%，主要碳源是农业化肥施用和农膜使用；（2）碳吸收增加了50.30万t，涨幅为27.31%，碳吸收强度涨幅为30.78%，蔬菜、水稻和其他粮食作物的碳吸收贡献比最大；由于碳吸收远大于碳排放，碳汇值均为正值，与1997年相比涨幅为26%，碳汇强度涨幅为29.50%；碳足迹与单位面积碳足迹比1997年相比均为增加态势，碳足迹增加0.11万hm²，涨幅为42.31%，单位面积碳足迹增加了0.011hm²/hm²，涨幅为45.45%，但24年间净碳足迹值均为负值。结论 近24年间重庆市江津区耕地利用处于碳生态盈余状况。

CARBON SINK AND CARBON FOOTPRINT CHANGE OF CULTIVATED LAND USE IN JIANGJIN DISTRICT AT THE END OF THREE GORGES RESERVOIR IN RECENT 24 YEARS

The global warming caused by the growth of carbon emissions is receiving increasing attention from all walks of life. As the carrier of carbon source and carbon sink, it is extremely important to analyze the evolution characteristics of carbon emissions of cultivated land. Based on the data of cultivated land use and agricultural data of Jiangjin district from 1997 to 2020, this paper measured the carbon absorption during crop fertility and carbon emissions during production. The results were showed as follows. (1) The carbon emissions, carbon absorption and carbon sink of cultivated land use in Jiangjin district all showed an increasing trend. Compared to 1997, the carbon emissions increased by 34,600 t, up to 86.86%, and the carbon emission intensity increased by 91.18%. The main carbon sources were agricultural fertilizer application and agricultural film use. (2) Carbon absorption increased by 50,300 t, with an increase of 27.31%, and carbon absorption intensity increased by 30.78%. Vegetables, rice and other food crops contributed the most to carbon absorption. The reason why carbon sink values were all positive was that carbon absorption was much greater than carbon emissions, with an increase of 26% compared to 1997, and carbon sink intensity had increased by 29.50%. Compared to 1997, both the carbon footprint and unit area carbon footprint showed an increasing trend, with an increase of 0.11 million hm² (42.31%) in carbon footprint and 0.011 hm² (45.45%) in unit area carbon footprint. Finally, it concludes that the net carbon footprint values are all negative over the past 24 years, indicating that the utilization of cultivated land in Jiangjin district is in a carbon ecological surplus state.