不同植被下中国土壤有机碳的储量与影响因子

基于第二次土壤普查和新疆土壤调查等 2 4 4 0个典型土壤剖面数据和 1∶4 0 0万中国植被图 ,对中国不同植被类型下的 1 0 0cm和 2 0cm厚度土壤有机碳密度和储量进行估算 ,绘制了土壤有机碳储量的地理分布图 ,并且对土壤有机碳储量与生境条件之间的关系进行统计分析。结果表明 :不同植被类型下的土壤有机碳密度存在显著差异 ,草甸和森林最高 ,灌木和农田次之 ,再其次是草原 ,最低的是荒漠 ;基于植被分类计算的我国 1 0 0cm和 2 0cm厚度土壤有机碳总储量分别为 6 9.38Gt和 2 3.81Gt。 1 0 0cm深度土壤碳储量在森林、农田、灌丛、草甸、草原、荒漠植被下分别为 1 7.39Gt、1 4 .6 9Gt、1 3.6 2Gt、1 2 .2 2Gt、7.4 6Gt、3.93Gt;土壤有机碳储量的空间分布差异明显 ,具有明显地域性 ,青藏高原东南地区、阿尔泰山和天山山地等高寒草甸、灌丛草甸区是土壤有机碳储量最高的地区 ,其次是东北地区北部的针叶林、草甸区和我国南方的亚热带阔叶林区 ,土壤有机碳储量最低的地区是西北地区和藏北高原的荒漠、草原干旱区 ;在不同生态系统中环境变量对土壤有机碳储量的影响是不同的 ,在温带草原年平均温度是土壤有机碳储量主要控制因素 ,而对于针叶林海拔是导致土壤有机碳储量变异的主导因子 ;随着研究尺度的细化 ,环境变

SOIL CARBON STOCKS AND THEIR INFLUENCING FACTORS UNDER NATIVE VEGETATIONS IN CHINA

Soil organic C plays a key role in carbon cycle and carbon storage in the natural ecosystem.The soil carbon stocks under native vegetations in China were estimated by making use of 2 440 profiles from the second national soil survey and the vegetation map (14 000 000) of China,and map the distribution of soil carbon density under native vegetations.With the aid of a simplified vegetation classification system,the digitalized vegetation map units were sorted into 6 categories and 26 types of vegetation.The median carbon stocks of the soils in China are 8.23 kg m^-2 in 0~100 cm soil layer,and 2.67 kg m^-2 in 0~20 cm topsoil.The difference in the soil carbon density among vegetation categories is prominent.The soil carbon density in 0~100 cm under forests,scrubs,deserts,steppes,meadows and croplands is 11.59,7.25,3.14,5.29,14.90 and 8.07 kg m^-2,re spectively.On the basis of vegetation types,the total soil carbon stocks were calculated at 69.38 Gt in 0~100 cm and 23.81 Gt in 0~20 cm.In 0~100 cm,the soil carbon stock under forests (17.39 Gt) was the highest,accounting for 25% of the total in China despite the fact that the forest soil amounted to only 15.81% of the total territory of the country.Under croplands,it was 14.69 Gt or 21.2%,a little higher than the percentage (19.18%) of the soil in area.Though the soil under the vegetation of meadows and swamps was low (8.64%) in percentage in area,its carbon storage amounted to 12.22 Gt or 17.63%.The soil carbon stocks under steppes were 14.69 Gt or 10.76% of the total,lower than the percentage (14.86%) of the soil in area,and it was 3.93 Gt or only 5.66% under deserts,much lower than the percentage (13.17%) of the soil in area.