Land-use effects on soil carbon and nitrogen in a typical plateau lakeshore wetland of China

Abstract

Wetland soils (WS) can store a significant amount of soil organic carbon (SOC) and total nitrogen (TN). Surface soils (0–20 cm) were sampled in WS, 20-yr-old conventionally tilled soils (CTS20), 2-yr-old abandoned tilled soils (ATS2), and 6-yr-old abandoned tilled soils (ATS6) to estimate changes in SOC and TN contents due to cultivation and abandonment. Our results showed that SOC and TN contents were significantly higher in WS than those in CTS20, ATS2, and ATS6. As a result of 20-yr cultivation, SOC and TN contents decreased from 43.75 to 24.06 g kg⁻¹ and from 4.96 to 2.32 g kg⁻¹, respectively. However, after the abandonment of cultivated wetlands, SOC and TN contents showed a slow increase but the change was not significant among CTS20 and ATS2. The findings of this study suggest that SOC and TN contents in top 20 cm soils of wetlands can be reduced significantly by cultivation, but they are restored slowly after abandonment.

Keywords:

• soil organic carbon
• total nitrogen
• wetland soils
• tillage
• abandonment

Acknowledgements

We express our thanks to the members of the project who provided invaluable support during the course of collecting soil samples and chemical analysis of the soil samples.

Funding

This work was financially supported by the National Natural Science Foundation [grant number 51179006]; the Programme for New Century Excellent Talents in University [grant number NCET-10-0235]; the Fok Ying Tung Education Foundation [grant number 132009].