荒漠草原碳酸盐岩土壤有机碳向无机碳酸盐的转移  

Transfer of soil organic carbon to soil inorganic carbon in carbonate rock soil of desert grassland

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

机构地区：[1]北京林业大学水土保持与荒漠化防治教育部重点实验室,北京100083 [2]内蒙古农牧科学院,内蒙古呼和浩特010010

出　　处：《干旱区地理》2010年第5期732-739,共8页Arid Land Geography

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：通过在内蒙古中西部四子王旗荒漠草原土壤剖面采集土样,拟分析测定土壤有机碳（SOC）含量、土壤无机碳酸盐（SIC）含量和SIC的δ13C值,探讨SOC向SIC的迁移转化过程及其转移量。结果表明：随深度增加,SOC含量逐渐降低而SIC含量依次增大,SOC与SIC含量具有明显的负相关关系。随土层加深,SIC的δ^13C值降低,在30 cm深度时相对最低为-8.6‰,而后增大,在深度为60 cm时其值为-5.8‰。说明通过＂SOC—CO2—SIC＂的微碳循环系统SOC向SIC发生碳的转移。应用碳稳定同位素技术和模型结合SIC的δ^13C值对该研究区SIC进行区分,发现30～50 cm土层次生碳酸盐（PC）所占比例为58.5%,50～60 cm土层为44.2%。应用δ13C值对该地区SOC向SIC的转化碳量进行估算,该地区30～60 cm土层每千克土壤中大约固定了SOC分解转化的4.97～5.9 g CO2。Collected soil samples of the desertification grassland at Siziwang County in western-central Inner Mongolia,China,the paper analyzed the SOC and SIC contents,the δ ^13C value of the SIC,and explored the migration processes and its transfer volume of the SOC to SIC.The results showed that the SOC content reduce gradually while the content of SIC increases with the soil depth increase.The content of SOC and SIC has obvious negative correlation.With the depth increased,the δ^ 13C value of the SIC decrease.As the depth approach to 30 cm,the minimum value is-8.6 ‰,and then increase.In the depth of 60 cm,the value is-5.8 ‰.This may proof that the carbon transfers from the SOC to SIC through the ＂SOC-CO 2-SIC＂ minor carbon cycle system.The paper applied the stable isotope techniques and models to distinguish the pedogenic carbonate soil from the total SIC.The proportion of pedogenic carbonate is 58.5% in 30-50 cm layers.In 50-60 cm layers,the proportion is 44.2%.With the δ 13C value to analysis the transfer content from SOC to SIC,the paper found that in 30-60 cm layers per kilogram soils can fix 4.97-5.9 g CO 2 from the decomposition of SOC,in the northwest arid areas.

关 键 词：荒漠草原 碳酸盐岩土壤 碳稳定同位素 碳转移 

分 类 号：S153[农业科学—土壤学]