中国沿海地区农田生态系统部分碳源/汇时空差异

Temporospatial Variation of Partial Carbon Source/Sink of Farmland Ecosystem in Coastal China.

运用1981—2001年作物产量、农业投入等统计数据,对沿海10个省市自治区农田生态系统部分碳源/汇进行了估算,得到以下主要结论:(1)总碳吸收从1981年以来呈波动增加趋势,总碳排放则呈明显增长趋势。二者相比,碳排放明显低于碳吸收,但由主要途径农业投入导致的间接碳排放的增长速度(94%)超过了作物生育期碳吸收的增长速度(44%)。(2)各省市自治区碳吸收、碳排放变化的区域差异显著,单位面积碳吸收、碳排放变化的差异也十分明显。其中,各省市自治区总碳排放和单位面积碳排放基本上逐年增加,表明沿海发达地区农业投入较高;而碳吸收变动幅度较大,发达地区(如浙江、福建和上海等)碳吸收呈下降趋势,反映沿海地区农作物种植面积下降致使农作物生育期总碳吸收量降低。(3)沿海地区农田生态系统主要粮食作物碳吸收占全国比例有所下降,说明沿海地区农业种植面积减少和农业投入增加削弱了农田生态系统的碳汇功能。

Based on the statistic data of crop yield and agricultural input in the period from 1981 to 2001 ,carbon sources and sinks of the farmland ecosystems in the 10 coastal provinces ,metropolises and autonomous regions of China were estimated. Conclusions are reached as follows ： （ 1 ） The total carbon sink of the farmland ecosystem in coastal China was zigzagging upward since 1981 ,and the total carbon emission climbing rapidly. But comparison shows the former went at a higher rate than the latter. However,the increasing rate （94%） of the indirect carbon emission caused by agricultural input exceeds that of carbon sink （ 44% ） during the crop growing season. （ 2 ） Significant temporospatial variation is observed of total carbon sink and emission and of carbon sink and emission per unit area between different regions and among them, both total emission and emission per unit area showed a rising trend with each passing year. The drastic variation of the carbon sink in developed regions is a result of relatively higher agricultural input. The total carbon sink in relatively developed regions showed a downward trend from 1981 to 2001 ,which indicates that decreased acreage of farmland in the costal regions reduced carbon sink during the crop growing season. （3） The proportion of carbon fixed by the main crops in the farmland ecosystem of the coastal region against that of the whole nation＇s was decreasing,which indicates that with the decrease in acreage of cropland and increase in agricultural input,the carbon sink function of the coastal region is weakened.