基于碳足迹的江西省农田生态系统碳源/汇时空差异

利用2001~2010年江西省农业投入和农作物统计数据，采用碳排放系数法计算了江西省农田生态系统碳源/汇及碳足迹，分析了江西省农田生态系统碳源/汇时空特征，并进一步分析了碳足迹变化特征及原因。结果表明：(1)2001~2010年，江西省农业投入引起的碳排放量从2001年的11910 1×106 t，增加至2010年的5872 8×106 t，增加了103倍，农业机械化对碳排放总量贡献率最大。碳排放强度呈现先增加后减少的趋势。2008年赣州市碳排放量最多，景德镇市最少；(2)2001~2010年江西省农田生态系统碳吸收量先减少，后逐年增加，到2010年又减少，整个2001~2010年间增加3209 9×106 t。各类农作物中，水稻碳吸收量最多。2009年碳吸收量最多的是宜春市，最少的是萍乡市;(3)江西省农田生态系统碳足迹从2001年的07518×106 C〖DK〗·hm-2〖DK〗·a-1，增加至2009年的1473 4×106 C〖DK〗·hm-2〖DK〗·a-1,单位面积碳足迹呈现逐年增加的趋势。2008年碳足迹最多的是赣州市，最少的是萍乡市。南昌市、景德镇市、吉安市和宜春市表现为生态盈余，其余表现为生态赤字。江西省应减少农药、化肥等的使用，控制农业机械化，特别是赣州市，从而达到减少碳排放的目的

SPATIAL TEMPORAL DYNAMICS OF FARMLAND ECOSYSTEM CARBON SOURCE/SINK BASED ON CARBON FOOTPRINT IN JIANGXI PROVINCE 

The processes of terrestrial ecosystem carbon cycle and source change are key scientific problems in global climate change and ecology now. We used statistic data in Jiangxi Province from 2001 to 2010, and the carbon emissions coefficient method to calculate the carbon source/sink of farmland ecosystems and carbon footprints in Jiangxi Province, and analyzed the spatiotemporal differences of carbon source/sink and the changes and reasons of carbon footprints. The results showed as follows. (1) From 2001 to 2010, carbon emissions caused by farmland use in Jiangxi Province increased by 103 times, from 11910 1×106 t in 2001 to 5872 8×106 t in 2010. Agricultural mechanization was the biggest contribution to farmland ecosystem carbon emissions in Jiangxi Province. Carbon intensity of farmland ecosystems in Jiangxi Province showed a trend of increased followed by decreased as a whole. With respect to the regional difference, Ganzhou had the largest farmland ecosystem carbon emissions in Jiangxi Province in 2008; Jingdezhen was the minimum, and its carbon emissions intensity was also the lowest. (2) Carbon uptake of farmland ecosystem in Jiangxi Province during 2001-2010 decreased at first, then increased year by year, and decreased in 2010; the whole carbon uptake from 2001 to 2010 increased by 3209 9×106 t. All kinds of crops, rice had the largest carbon uptake, accounting for more than 75%. From the point of carbon absorption intensity, farmland ecosystem carbon intensity in Jiangxi Province was enhanced followed by weakened. From a regional view, Yichun had the most carbon uptake in various districts of Jiangxi Province in 2009, while Pingxiang had the least. The highest carbon absorption intensity was Fuzhou city, while Jiujiang was the weakest. (3) The carbon footprint of farmland ecosystem in Jiangxi Province rose from 0751 8×106 C〖DK〗·hm-2〖DK〗·a-1, to 1473 4×106 C〖DK〗·hm-2〖DK〗·a-1 in 2009, increased by 0698 1×106 C〖DK〗·hm-2〖DK〗·a-1, and per unit carbon footprint presented an increasing trend year by year. From the perspective of the regional differences, Ganzhou was the most carbon footprint city in Jiangxi Province in 2008, while Pingxiang was the least. The per unit carbon footprint of Ganzhou was the largest, while Jian was the smallest. Nanchang, Jingdezhen and Yichun performed ecological surplus, while other seven regions showed ecological deficit. Ganzhou had the largest ecological deficit, while Yingtan city had the least deficit. Conclusion: Jiangxi Province should reduce the use of pesticides, fertilizers, etc., and control the utilization of agricultural mechanization, especially in Ganzhou city, in order to achieve the purpose of reducing carbon emissions