不同放牧强度下荒漠草原土壤有机碳及其δ^(13)C值分布特征  

Distribution Characteristics of Soil Organic Carbon and Its Stable Carbon Isotope Composition in Desertification Grassland under Different Grazing Intensities

作　　者：张林[1] 孙向阳[1] 乔永[1] 高程达[1] 曹吉鑫[1] 阿拉塔 宝音贺希格 

机构地区：[1]北京林业大学水土保持学院,北京100083 [2]内蒙古农牧科学院,呼和浩特010031

出　　处：《水土保持学报》2009年第6期149-153,共5页Journal of Soil and Water Conservation

基　　金：国家自然基金(30671660);教育部新世纪优秀人才支持计划(NCET-05-0137);教育部高等学校博士学科点专项科研基金(20050022014)

摘　　要：以内蒙古短花针茅荒漠草原为研究对象,通过测定不同载畜率下土壤部分理化性质、土壤有机碳含量和δ13C值,探讨随放牧强度增加土壤有机碳深度分布和δ13C值的组成差异特征。结果显示:随深度增加,有机碳含量呈线性急剧降低,变化范围在16.17～6.26g/kg之间;而土壤有机碳的δ13C值不断增大,变化范围在-22.5‰～-14.3‰。放牧对土壤有机碳的影响主要在0-20cm土层,且放牧强度越大,有机碳含量越低,有机质分解程度越大,δ13C值越偏正。δ13C值的深度变化特征还表明,土壤剖面形成发育过程中当地气候和植被发生了很大的变化,可能实现了由C4植物占优势向C3植物占优势的变迁。Stipa breviflora desertification grassland in Inner Mongolia were selected as a case to study effect of spatial distribution Characteristics of soil organic carbon and difference in stable carbon isotope composition with the increase of grazing. The results showed that the soil organic carbon contents showed a sharp linear decrease with the depth increasing,being 16.17～6.26 g/kg,but with the depth increase the δ^13C value of soil organic carbon also increasing,and the δ^13C value are between -22.5 ‰～-14.3 ‰. The influence of grazing on soil organic carbon mainly in 0-20 cm layer,and the greater the grazing intensity,the lower the soil organic carbon contents,the greater the degree of organic matter decomposition,and the great the δ^13C value. The spatial distribution characteristics of δ^13C also shows that the local climate and vegetation changed a lot when soil profile development process,and experienced the changes of C4 to C3 in the dominant plant possibly.

关 键 词：放牧强度 短花针茅荒漠草原 土壤有机碳 δ^13C值 

分 类 号：S155.47[农业科学—土壤学] S153.6[农业科学—农业基础科学]