摘要
定量分析了青藏高原各类草地 0～ 0 65m深度范围内有机碳储量 ,结果表明 :青藏高原总面积为 1 60 2 7× 1 0 8hm2 的草地有机碳量达到 335 1 973× 1 0 8tC ,其中以高原草甸土和高原草原土有机碳积累量为主 ,两者之和达到 2 32 36× 1 0 8tC ,占全国土壤有机碳量的 2 3 44% ,是全球土壤碳库的2 4% .在有机碳储量分析的基础上 ,按土壤碳释放的两种主要途径 :土壤呼吸作用和土地利用方式变化与草地退化 ,对草地土壤碳排放进行了估算 ,揭示出青藏高原草地土壤通过呼吸每年排放的CO2 达到 1 1 78× 1 0 8tC·a- 1 ,约占中国土壤呼吸总量的 2 8 3 % ,明显高于全国乃至全球平均值 ;近 30a来 ,青藏高原草地土壤由于土地利用变化和草地退化所释放的CO2 估计约有 30 2 3× 1 0 8tC .
A study of carbon (C) storage in the range of 0～0 75 m deep of soils of various grasslands on the Tibetan Plateau was carried out. It is found that there are 1 627 million km 2 of grasslands in the plateau, where organic carbon content reaches 33 52 Pg of C. Organic carbon is mainly stored in meadow and steppe soils, reaching 23 2 Pg of C stored in organic form. This accounts for 23 44% of China s total organic soil stored carbon or 2 5% of the global soil carbon pool. Carbon emission from the grasslands was estimated, based on the two major modes of emission: (i) natural soil respiration and (ii) shifts in net C flux to/from soil due to land use change and their potential influence on organic matter decomposition. CO 2 emission from the grasslands of the plateau driven by annual soil respiration reaches 1 17 Pg·a -1 of C, accounting for 26 4% of China s total soil respiration or 1 73% of global soil respiration. Because the grasslands is accounted for 1 02% of the global terrestrial area or 16 9% of China s total terrestrial area, this CO 2 emission rate is significantly higher than the mean annual rate of China (about 4 2 Pg·a -1 of C ), and even higher than the global mean rate (about 68 Pg·a -1 of C). In the last 30 years, about 3 02 Pg of C have been emitted from the grasslands of the plateau due to change in land use and grassland degradation. The total CO 2 emission rate from the grasslands of the plateau reaches 1 27 Pg·a -1 of C. Protecting grasslands on the plateau is of great importance for limiting global climate change.
出处
《冰川冻土》
CSCD
北大核心
2002年第6期693-700,共8页
Journal of Glaciology and Geocryology
基金
中国科学院知识创新工程项目 (KZCX1 10 0 6 )
国家自然科学基金项目( 90 10 2 0 0 6 .)
中国科学院"西部之光"项目资助
