### Soil Organic δ13C Change Along a Vertical Gradient in the Northern Slop of Tianshan Mountains

XU Wen-qiang1;LUO Ge-ping1;CHEN Xi1;FENG Yi-xing2;LI Chao-fan3

1. 1.State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; 2.Bureau of Land and Resources Reserve of Qiannan State, Duyun 558000, China; 3.Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
• Online:2016-08-20 Published:2016-08-10

### 天山北坡土壤有机碳δ13C组成随海拔梯度的变化

1. 1.中国科学院 新疆生态与地理研究所，荒漠与绿洲生态国家重点实验室，新疆 乌鲁木齐830011;2.贵州省黔南州国土资源储备局，贵州 都匀558000;3.中国科学院 南京土壤研究所，江苏 南京210008

Abstract:

Soil organic carbon (SOC) pool integrated the vegetation succession information from several years to thousands of years scales. It is an ideal tool to understand carbon isotope composition change and terrestrial ecosystem pathways. In this study, the Sangong river watershed was taken as a case. We had estimated the change of vegetation and soil organic along a vertical gradient using the carbon isotopic method, and analyzed the variations of mean SOC δ13C values with the annual precipitation, and researched the variations in SOC and δ13C values with profile depth in the study area. The results showed that the SOC δ13C decreased significantly with the increasing annual precipitation (R2=0.97) where the annual precipitation was less than 300 mm. When the annual precipitation was 300 mm~500 mm, the SOC δ13C was not significant changed with the increasing annual precipitation (R2=0.04). The enrichment effect of SOC δ13C with depth was significant in the sample site of pure C3 vegetation, that means lower layer SOC δ13C of profile was greater than the upper layer. The average difference of SOC δ13C between lower layer and upper layer was 1.01‰. The opposite trend of SOC δ13C was presented in the Desert and Shrubland sites. And that, the SOC δ13C value of upper layer closed to C4 vegetation source, and the lower layer closed to C3 vegetation source. Therefore, we can infer that the vegetation may have experienced from C3 to C4 in the sandy desert and terrene desert sites.