Impact of soil and water conservation on soil organic carbon content in a catchment of the middle Han River, China
2015
Xu, Guoce | Lu, Kexin | Li, Zhanbin | Li, Peng | Wang, Tian | Yang, Yuanyuan
Soil organic carbon (SOC) is essential for improving soil quality, sustaining food production and quality, and maintaining water quality, as well as for mitigating climate change. Understanding the impact of soil and water conservation on SOC content is important for the protection of soil and water quality. In this study, the impacts of soil and water conservation on SOC content and density in a small catchment of the middle Han River were studied based on a grid soil survey. A total of 583 soil samples from 207 sites were collected, primarily from 30 m × 30 m grids. The results indicated that SOC content generally decreased with increasing soil depth, and significant differences existed among the three examined soil layers (0–20, 20–40, and 40–60 cm, p < 0.01). The mean SOC content of the different land use types occurred in the following order: forestland > terraces > grassland > sloping cropland. The spatial variability of SOC decreased as soil depth increased. The mean SOC densities of terraces, forestland, grassland, and sloping cropland at the 0–60 cm soil depth were 4.40, 4.31, 3.86, and 3.62 kg/m², respectively. The high-value zones of SOC density were always observed in the upper slope and basin outlet. SOC storage in the 0–60 cm soil depth was 565.10 tons in the Yujiehe catchment. Land use was the main influencing factor for SOC content in the catchment. Forestland, grassland, and terraces exhibit higher SOC than does sloping cropland. In conclusion, the use of terraces can greatly increase SOC density. Much sloping cropland can be changed to terraces, forestland, or grassland to increase SOC and protect soil and water quality in the water source area of the Han River.
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