Abstract

Soil organic carbon (SOC) mineralization is closely related to carbon source or sink of terrestrial ecosystem. Understanding SOC mineralization under plum plantation is essential for improving our understanding of SOC responses to land-use change in karst rocky desertification ecosystem. In this study, 2-year, 5-year, and 20-year plum plantations and adjacent abandoned land dominated by herbs were sampled, and a 90-day incubation experiment was conducted to investigate the effect of plum plantations with different ages on SOC mineralization in subtropical China. Results showed that: (1) Plum plantation significantly decreased SOC content compared with abandoned land, but there was no significant difference in SOC content among plum plantations with different ages. Oppositely, the accumulative SOC mineralization (Ct) and potential SOC mineralization (C0) showed different responses to plum plantation ages. (2) The dynamics of the SOC mineralization were a good fit to a first-order kinetic model. Both C0 and Ct in calcareous soil of this study was several- to 10-folds lower than other soils in non-karst regions, indicating that SOC in karst regions has higher stability. (3) Correlation analysis revealed that both Ct and C0 was significantly correlated with soil calcium (Ca), suggesting an important role of Ca in SOC mineralization in karst rocky desertification areas. In conclusion, a Ca-rich geological background controls SOC mineralization in karst rocky desertification areas.

Highlights

  • Due to the fragile geological and ecological conditions, rocky desertification widely occurs in the southwest karst region of China [1], which is characterized by serious soil erosion, devoid of vegetation and soil [2]

  • Plum plantation significantly decreased pH and the contents of soil organic carbon (SOC) and TN (p < 0.05) (Table 1), but there was no significant difference among plum plantations with different ages (p > 0.05)

  • Plum plantation significantly reduced SOC content by about 50% compared with abandoned land, which may be attributed to the changes in agricultural managements

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Summary

Introduction

Due to the fragile geological and ecological conditions, rocky desertification widely occurs in the southwest karst region of China [1], which is characterized by serious soil erosion, devoid of vegetation and soil [2]. To effectively prevent rocky desertification, a series of ecological restorations have been carried out to increase the forest cover and to mitigate soil erosion by the Chinese government [3]. Various land uses, including undisturbed (e.g., grassland and shrub) and man-made (e.g., corn, woodland and fruit crop) ecosystems, have been formed in karst rocky desertification regions. These ecological restoration measures have tremendously affected the physical, chemical, and microbiological properties in soils [4]. Plum plantation is one of the local sustainable development models of characteristic agriculture in karst rocky desertification areas, which can effectively restore the ecological environment, and significantly increase farmers’ income in local.

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