河北省农田生态系统碳源/汇时空变化及其影响因素

基于1989-2008年河北省主要农作物产量、耕地面积、有效灌溉面积、化肥施用量及农业机械动力等方面的统计数据,估算了河北省近20a来农田生态系统碳源/汇,并探讨了碳源/汇时空变化及其影响因素。结果表明,近20a来河北省农田生态系统碳吸收总量总体呈现波动增加态势,碳排放总量也呈逐年上升的趋势,且碳吸收增长的速度大于碳排放的速度,总的来说,河北省农田生态系统是碳汇;从空间上来看,河北省碳汇强度由南向北逐渐降低;在各种作物中,小麦和玉米的碳吸收所占比重最大;对影响农田生态系统碳源/汇因素分析表明,农业灌溉对作物碳吸收影响最显著,其次是化肥施用,在农田生态系统3种主要碳排放途径中以化肥施用带来的碳排放所占的比重最大。

Temporal and Spatial Variation and Influence Factors of Carbon Source and Sink of Farmland Ecosystem in Hebei Province

Based on the statistic data of crop yield,planting area,effective irrigation area,fertilizer usage and agricultural machinery power of Hebei Province from 1989 to 2008,the carbon source and sink of the farmland ecosystems in Hebei Province were estimated.Furthermore,the temporal and spatial variations and the influencing factors of carbon source and sink were analyzed.The results showed that the total carbon sequestration and emission of the farmland ecosystems in Hebei Province showed a gradually rising process in the last 20 years,and more carbon was sequestrated than emitted.Overall,the farmland ecosystem of Hebei Province was a carbon sink.Spatially,the density of carbon sink declined from southeast to northwest.The carbon sequestrated by wheat and corn plants accounted for the largest proportion.In addition,the process of agricultural irrigation was the main controlling factor for carbon sequestration.The carbon emitted from fertilizers contributed the biggest proportion among the three major carbon emission sources of the farmland ecosystems.