摘要
应用稳定碳同位素技术测定土壤无机碳稳定碳同位素组成(soil inorganic carbonδ13C,SICδ13C),并对干旱区绿洲土壤无机碳进行区分,结合土壤有机碳(soil organic carbon,SOC)与SIC含量关系进一步探讨SOC向SIC转移的碳量.结果表明,4种类型土壤SICδ13C值差异性极显著(P<0.01),风沙土SICδ13C值最高且为正,均值为(0.32±0.04)‰,随土层深度增加而增加,说明风沙土原生性碳酸盐占绝对优势;灌漠土、棕漠土和盐碱土SIC的δ13C均值分别(-0.30±0.24)‰、(-1.96±0.66)‰和(-1.24±0.49)‰,随土层变化均呈先降低后逐渐增大的趋势,说明灌漠土原生性碳酸盐占优势,棕漠土和盐碱土发生性碳酸盐相对前者占优势.风沙土、灌漠土、棕漠土和盐碱土的发生性碳酸盐占SIC比例均值分别为1.33%、4.72%、15.01%、35.71%,均小于50%,说明干旱区绿洲土壤发生性碳酸盐比例总体水平较低.风沙土、灌漠土、棕漠土和盐碱土在土壤发生性碳酸盐形成或重结晶过程中固定土壤CO2的量分别为0.30、2.44、4.96、12.40 g·kg^(-1),其中固定来自大气CO2量平均为0.18、0.79、1.45、8.67 g·kg^(-1),来自SOC氧化分解转化为CO2的量分别为0.06、0.83、1.62、1.86g·kg^(-1),说明盐碱土、棕漠土SOC的贡献相对较高,灌漠土、风沙土较低;对土壤固定CO2量的来源比较发现,风沙土、盐碱土固定土壤CO2的量来自大气CO2量较高,SOC的贡献较低,而灌漠土、棕漠土固定来自SOC氧化分解CO2的量较高,大气贡献较低.研究区整体SOC向SIC的碳转移量介于0.03~2.38 g·kg^(-1)之间,平均每千克土壤固定1.09 g的CO2,说明干旱区绿洲土壤发生性碳酸盐所占比例较低,SOC的贡献较少.
The northern margin oasis of the Tarim Basin in the central arid region of Asia was selected as the study area. The study analyzed the δ13C values of the SIC（ soil inorganic carbon） and distinguished the pedogenie carbonate in soil from the total SIC using the stable carbon isotope techniques and models. Based on the relationship between soil organic carbon and inorganic carbon contents in soil, the transfer of SOC to SIC was discussed. The results showed that the δ3C values of the SIC of 4 types of arid oasis soil were significantly different （P 〈 0. 01 ） , the δ13C values of the SIC of aeolian sandy soil was （0. 32 ± 0. 04 ） %o, which increased with increase in depth. This indicates that the lithogenic carbonates of the sandy soil are advantageous. The δ13C values of the SIC of irrigated desert soil, brown desert soil, and saline soil were （ -0.30 ±0.24）%o, （ - 1.96 ±0.66）%o and （ - 1.24 ±0.49）%o, respectively, and decreased with increase in depth. This indicates that the lithogenie carbonates dominated the irrigated desert soil, and the pedogenic carbonates dominated brown desert and saline soils. In the aeolian sandy, irrigated desert, brown desert, and saline soils, pedogenic carbonate accounted for 1.33% , 4. 72% , 15.01% , and 35.71% of SIC, respectively, which were less than 50% . This shows that the level of soil pedogenie carbonates was low in arid oasis. During pedogenic carbonate formation or recrystallization, the aeolian sandy, irrigated desert, brown desert, and saline soils fixed 0.30, 2.44, 4.96, and 12.40 g＇kg-1 of soil CO2, respectively, the average amount of CO2 fixed from the atmosphere was 0. 18, 0.79, 1.45, and 8.67 g＇kg-l, respectively. Furthermore, the transfer of SOC to SIC was 0. 06, 0. 83, 1.62, and 1.86 g· kg -1 , respectively. The total transfer of SOC to SIC was between 0.03 and 2.38 g·kg-1 , with an average of 1.09 g·kg-1 of COz. This shows that the proportion of soil pedogenic carbonates and the contribution of SOC were not high in the arid
作者
李杨梅
贡璐
安申群
孙力
陈新
LI Yang-mei;GONG Lu;AN Shen-qun;SUN Li;CHEN Xin(College of Resources and Environment Science,Xinjiang University,Urumqi 830046,China;Key Laboratory of Oasis Ecology,Ministry of Education,Xinjiang University,Urumqi 830046,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2018年第8期3867-3875,共9页
Environmental Science
基金
国家自然科学基金项目(41461105)
新疆维吾尔自治区科技厅优秀青年科技人才培养项目(qn2015yx002)
新疆维吾尔自治区教育厅研究生科研创新项目(XJGRI2016023)
