区域农田生态系统碳足迹时空差异分析——以江苏省为案例

以江苏省为案例,应用江苏省1995—2009年化肥用量、农药消耗量、灌溉面积、农机燃料用量、农膜用量、耕地面积、农作物产量等数据,测算了区域农田生态系统碳吸收、碳排放及碳足迹的变化动态,以及在各地市的空间分布特征。结果表明:近15a来,江苏省农作物碳吸收总量和碳吸收强度呈"V"字形变化,变化范围分别为2933.6×104～3896.9×104t·a-1和6.04～7.71t·hm-2·a-1。农业投入碳排放呈逐渐上升趋势,由727.2×104t·a-1增长至882.7×104t·a-1,同时碳排放强度从1.43t·hm-2·a-1上升到1.88t·hm-2·a-1,增长了31.5%,化肥排放始终占据主导地位。农田生态系统碳足迹呈现波动增长,变化在13.68×105～17.56×105hm·2a-1之间,占同期耕地面积的比重达到27.0%～36.1%,碳生态盈余呈明显减少趋势,变化在36.99×105～32.22×105hm2·a-1之间。各地市之间碳足迹存在明显差异,空间分布格局为由北向南递减。

Temporal and Spatial Difference in Carbon Footprint of Regional Farmland Ecosystem——Taking Jiangsu Province as a Case

In this paper,the dynamic changes and spatial distribution characters of carbon absorption,carbon emission,and carbon footprint of farmland ecosystem were estimated based on the statistical data of consumption amount of chemical fertilizer,pesticide,plastic film,fuel used by agricultural machine,and irrigated area,arable land area,and crop yield from 1995 to 2009 in Jiangsu Province and different regions.The results showed that the dynamic of crop carbon absorption amount shaped like a "V",decreased first and then increased in last 15 years,changing from 2 933.6×104 t·a-1 to 3 896.9 ×104 t·a-1.Carbon absorption intensity varied in the range of 6.04 t·hm-2·a-1 to 7.71 t·hm-2·a-1.During the period,both of total carbon emission amount and emission intensity from agricultural inputs showed the rising trends from 727.2×104 t·a-1 up to 882.7×104 t·a-1 and from 1.43 t·hm-2·a-1 up to 1.88 t·hm-2·a-1,respectively.And the carbon emissions from chemical fertilizer had been the most important carbon emission source in all agricultural inputs,but the carbon emission from agricultural machine kept a fastest growing.Carbon footprint of farmland ecosystem increased slowly with a fluctuation range of 13.68×105 hm2·a-1 to 17.56×105 hm2·a-1,accounting for 27.0% to 36.1% of cultivated land area,while carbon ecological surplus showed a trend of decrease during the period.There were obvious differences between the regions in Jiangsu,and the spatial distribution appeared that the southern regions were usually less than the north regions.The estimates presented here are based on limited evidence and parameters,and have an uncertainty associated with them,further studies are need.