中国农业净碳汇时空演化特征分析

论文以全国范围县级单元为研究对象,对1991—2011年长达21 a的农业净碳汇时空格局变化规律展开了深入分析。研究表明：1）从时间变化角度可以发现,整体上我国农业在长达21 a内均以净碳汇为主,并且总体上处于波动上升趋势,农业净碳汇净增93.7%;2）我国农业碳汇结构相对比较稳定,稻谷、小麦和玉米三者共同占到了80%左右,而碳源结构则在1991—2011年间发生了较大变化,由1991年农药为主,化肥、牛为辅转变成为化肥为主,农药、地膜、牛为辅的结构;3）空间分布方面,我国县域农业净碳汇量地区间差距在不断缩小,存在4种农业碳生态类型区;4）1991—2011年间净碳汇为负值的县级单元数量增多,并且在空间上主要分布于西南地区与内蒙古。农业种植量相对较小,作物生长碳吸收不明显,单位产量农业投入要素多以及农业类型以畜牧业为主是这些地区农业净碳汇为负值的主要原因。

Spatial-temporal Characteristics of China’s Agricultural Net Carbon Sink

This article uses the county-level dataset to analyze the spatial-temporal characters of agricultural net carbon sink from 1991 to 2011 in China. Research shows that: 1) Overall, the agricultural net carbon sink is positive and increasing, with a net increase of 93.7% during this period. 2) The structure of agricultural carbon sink is relatively stable with rice, wheat and maize accounting for about 80% all together, while the structure of carbon source in the same period changed greatly that the main contributing factor of the carbon source changed from pesticide to agricultural fertilizer. 3) The spatial distribution shows the gap of agricultural net carbon sink among regions is narrowing, and there exists three kinds of agricultural carbon ecological zones. 4) During the period of 1991-2011, counties with negative net carbon sink increased in amount and mainly located in the Southwest China and Inner Mongolia. The decreasing agricultural activities, low absorption of carbon during the growth of agricultural grains, more agricultural input factors, and livestock-leading agricultural activities in these regions may be the main reason.