黄土高原沟壑区梁坡地土壤有机碳质量分数与土地利用方式的响应

Changes in soil organic carbon under different land use types in slope land in gully region of Loess Plateau

通过对比分析陕西省王东沟流域梁坡地上农地、果园、人工林地、草地和苜蓿Medicago sativa地土壤有机碳质量分数及其在土壤剖面上分布差异,研究土地利用方式对土壤有机碳的影响。结果表明:果园土壤有机碳质量分数比农地低2.2%,人工林地、草地和苜蓿地分别比农地高25.3%,17.1%和11.6%;土壤有机碳质量分数在土壤剖面上随着土层的加深而降低,不同土地利用方式下土壤有机碳在剖面上的分布特征不同。不同土地利用方式下,土壤全氮与土壤有机碳存在极显著相关关系。

Soil erosion is serious in the Loess Plateau and soil organic carbon （SOC） in this area is lower than the average in China. SOC is a large component of the global carbon cycle and an important index to evaluate soil quality. In order to understand impact of vegetation on SOC at slope of Wangdonggou Watershed in Gully Region of Loess Plateau, SOC level and distribution characteristic along a slope under vegetation types were investigated. Through comparing the concentration of SOC and its distribution in soil profiles under crop land, orchard, forest land, grass land and clover land, the results demonstrated that compared with crop land, SOC content increased by 25.3%, 17.1% and 11.6% for forest land, grass land, clover land and decreased by 2.2% for orchard. The SOC content and the distribution in soil profile would change with the change of land use typs in slope land in gully region of Loess Plateau. In addition, there was a significantly correlation between TSN and SOC. [ Ch, 1 fig. 3 tab. 16 ref.]