荒漠草原土壤次生碳酸盐形成和周转过程中固存CO_2的研究  

CO_2 SEQUESTRATION IN FORMATION AND TURNOVER OF PEDOGENIC CARBONATES IN SOIL OF DESERT STEPPE,INNER MOGOLIA,CHINA

作　　者：张林[1] 孙向阳[1] 高程达[1] 乔永[1] 李素艳[1] 

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

出　　处：《土壤学报》2011年第3期578-586,共9页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(30671660);教育部新世纪优秀人才支持计划项目(NCET-05-0137)和教育部高等学校博士学科点专项科研基金(20050022014)联合资助

摘　　要：次生碳酸盐是干旱、半干旱地区土壤碳库的一个重要组成部分,较有机碳库大2倍-5倍,其形成与周转对该地区土壤碳平衡具有十分重要的意义。本文以内蒙古四子王旗短花针茅荒漠草原为研究对象,拟通过分析测定土壤碳酸盐（SC）含量及其δ^13C值、土壤CO2的δ^13C值和母质风化物的δ^13C值等,探讨土壤次生碳酸盐形成和重结晶过程中对土壤CO2的固定,并计算其固定量。结果表明：次生碳酸盐的δ^13C值主要由土壤CO2的碳同位素组成决定,可用土壤CO2的δ^13C值计算次生碳酸盐的δ^13C值。对该研究区SC进行区分,发现在40-50、50-60、60-80和80-100 cm土层,次生碳酸盐所占的比例分别为83.6%、65.4%、41.7%和17.4%。应用δ^13C值和化学平衡原理估算该地区次生碳酸盐形成和重结晶过程中固定的CO2量,得出40-50、50-60、60-80和80-100 cm土层每千克土壤中分别固定了38.3、39.2、25.1和9.2 g的土壤CO2。Pedogenic carbonates（PCs） are important components of the soil carbon（SC） pools in arid and semi-arid regions,and the pool of PCs is 2-5 times bigger than that of soil organic carbon therein.Formation and turnover of the PCs plays a significant role in balance of soil carbon in the regions.Soil samples were collected from a Stipa breviflora dominated desert steppe in Inner Mongolia for analysis of content and δ^13C of soil carbonates,δ^13C of CO2 and δ^13C of parent rocks,hence to explore effect of formation and turnover of pedogenic carbonates on sequestration of CO2 and calculate the amount of CO2 sequestrated.Results show that the δ^13C value of PCs was determined mainly by the composition of carbonate isotopes of soil CO2 and could be figured out with the aid of the δ^13C value of soil CO2.Fractionation of the SC in the study area revealed that PCs accounted for 83.6%,65.4%,41.7% and 17.4% in the soil layers of 40-50,50-60,60-80 and 80-100 cm,respectively.With the help of δ^13C values and the principles in chemical balance,the amount of CO2sequestrated during the process of PCs formation and turnover was worked out,being 38.3,39.2,25.1 and 9.2 g kg^-1soil in these layers,respectively.

关 键 词：荒漠草原 碳酸盐 次生碳酸盐 δ^13C值 土壤CO2 

分 类 号：S153.4[农业科学—土壤学] X142[农业科学—农业基础科学]