中国土地沙漠化对大气CO_2含量的影响

ATMOSPHERIC CO_2 CONTENT AFFECTED BY DESERTIFICATION IN CHINA

本文根据我国不同地区沙漠化类型的面积、土壤有机碳的含量及沙漠化的正逆转速率，计算了我国沙漠化土地中有机碳的变动。结果表明，我国沙漠化土地０－５０ｃｍ土层中有机碳的，总贮量为７５３．１４３Ｍｔ，近４０年来因土地沙漠化而释放到大气中的ＣＯ２，总量达１７３．２８６Ｍｔ，而逆转过程中固定的ＣＯ２量为５９．１２４Ｍｔ碳，所以，近４０年来我国沙漠化土地净释放到大气中的ＣＯ２量为１２４．４７５Ｍｔ碳，占全球温带和寒带土地每年释放ＣＯ２量１３３Ｍｔ碳的９３．５％。

The paper,according to areas and conversion rates( positive and negative)of desertified lands, contents of organic carbon in soils, calculates the quantitative dynamics of China desertified lands, the results show: The organic carbon stored in0-50cm soil layers of national desertified lands amounts to 753.143Mt; over the recent 40 years, 173. 286Mt of CO2 are released from desertified lands, however, only 59.124Mt of CO2 are fixed In the reverse processes to desertificafion; that is, China desertified lands have released 124.475Mt of CO2 into the air over the 40 years.