河西绿洲农田生态系统碳源/汇的时空差异研究

Research on the temporal-spatial differences of carbon sources and sinks of farmland ecosystems of Hexi oasis in Gansu

研究了1949-2005年甘肃河西绿洲农田生态系统部分碳吸收、碳排放以及净碳汇,结果表明,1)1949-2005年河西绿洲农田生态系统碳吸收呈阶段性增长趋势,碳吸收总量从1949年的24.39万t增加到2005年的298.37万t,净增加273.98万t,增长了12.23倍。2)1949-2005年河西绿洲农田生态系统碳排放呈急剧增加的态势,从1949年的0.25万t增加到2005年的75.70万t,净增加75.45万t,增长了302.8倍。其中肥料施用导致的间接碳排放所占比例最大,且增速最快;而农业机械带来的碳排放最低,保持较低水平,基本上呈持平状态。3)1949-2005年河西绿洲农田生态系统净碳汇与碳吸收大致相同,也呈阶段性增长趋势,说明碳吸收明显大于碳排放,进而表明河西绿洲农田生态系统具有较强的碳汇功能,但是碳排放的增长速度远远超过了碳吸收,这种形势不容乐观。

Temporal-spatial differences of carbon sources and sinks of farmland ecosystems of Hexi oasis in Gansu in 1949-2005 were studied. 1） Carbon absorption of farmland ecosystems showed an increasing trend from 243.9 thousand tons in 1949 to 2 983.7 thousand tons in 2005, a net increase of 2 739.8 thousand tons （a 12.23 fold increase）. 2） Carbon emissions from the farmland ecosystem of the Hexi oasis in Gansu in 1949-2005 showed a rapid, increasing trend from 2.5 thousand tons in 1949 to 757 thousand tons in 2005, a net increase of 754.5 thousand tons （a 302.8 fold increase）. Fertilizer use played a leading role, and showed a rapid increase. Carbon emissions from agricultural machinery were low on the smooth terrain. 3） There was an increasing trend of net carbon sink in the farmland ecosystems of the Hexi oasis in Gansu in 1949-2005. Carbon absorption was more than carbon emission of these farmlands and farmland ecosystems had a large carbon sink capability. However, the increasing speeds of carbon emissions compared with carbon absorption do not give a reason ity. However, the increasing speeds of carbon emissions compared with carbon absorption do not give a reason for optimism.