LI Yacui1, JI Hongbing1,2, ZHANG Tao1, HAO Yating1
(1 Capital Normal University, Beijing 100048, China;
2 University of Science and Technology Beijing, Beijing 100083, China)
Abstract: Distributions of contents of soil organic carbon (SOC) and total nitrogen (TN) as well as their stable isotope compositions (δ13C and δ15N) along four typical soils profiles, grassland (SL1), garden area (SL2), forest land (DP), wasteland (XNC) and residential land (QST), in the Shilin area were studied. Results showed that: (1) in the upper soil layer (0-10 cm), SOC contents showed a trend of QST (29.25 g/kg) > SL1 (21.53 g/kg) > SL2 (21.18 g/kg) > XNC (9.42 g/kg) > DP (9.19 g/kg), along the profile from top to bottom, SOC contents decreased gradually and then reached stable values, except SL1, which showed a zigzag trend, while C/N ratios decreased along all soil profiles; (2) generally, δ13C values of soil organic matter (SOM) increased downward along the soil profiles, specifically, the variation of δ13C along the QST profile showed a consistently increasing trend, it started with an increasing trend then followed by a decreasing trend and then became a relatively stable value along SL1, SL2 and XNC profiles, and it started with a decreasing trend then followed by an increasing trend and then showed a "S" shape variation after certain depth along the DP profile; (3) the δ15N values of SOM showed no consistent variation along the four soil profiles. In summary, we believed that the different sources and decomposition degrees of SOM, which may be controlled by soil pH, vegetation type and human disturbance degree, are important factors affecting SOC, TN, δ13C and δ15N contents of soils in different land use type sites of the Shilin area.
Key words: Shilin area; land use types; soil organic carbon; total nitrogen; stable carbon and nitrogen isotopes
EARTH AND ENVIRONMENT Vol.46, No.5, Tot No.325, 2018, Page 437-443
