Institute of Earth Sciences, China University of Geosciences (Beijing), Beijing 100083, China.
School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China.
Int J Environ Res Public Health. 2020 Jan 28;17(3):801. doi: 10.3390/ijerph17030801.
Soil erosion has become a serious ecological problem in many catchments. Soil erodibility K factor can be estimated based on a series of soil properties, however, the identification of dominant soil properties that affect K factor prediction at different soil types has been little concerned. In this study, 3 soil profiles from the Jiulongjiang River Catchment (JRC) of granite region in Fujian province and 18 soil profiles from the Chenqi Catchment (CC) of karst region in Guizhou province were selected. Soil properties, including soil particle size distribution, soil organic carbon (SOC) and soil organic nitrogen (SON) content, and soil pH, were determined, and the K factors were estimated in the erosion productivity impact calculator (EPIC) model. The soils in the granite region were characteristic for coarse texture, low SOC and SON, and strong acidity compared with limestone soils. Although the K factors in both regions ranged from 0.009 to 0.018, they were overestimated in limestone soils due to frequent soil aggregation, which enhanced soil permeability, hence reduced soil erodibility. The results of principal component analysis (PCA) and structural equation model (SEM) showed that (1) K factor estimation in the soils of the granite region mainly depended on soil texture, of which silt was the most important factor; (2) while K factor in limestone soils was mainly controlled by soil organic matter (SOM) content, other soil properties, including soil pH, clay and silt contents, could indirectly affect prediction of K factor by affecting SOM accumulation.
土壤侵蚀已成为许多集水区的严重生态问题。土壤可蚀性 K 因子可以根据一系列土壤特性来估算，然而，对于影响不同土壤类型 K 因子预测的主要土壤特性的识别却很少受到关注。本研究选取了来自福建省花岗岩区九龙江集水区（JRC）的 3 个土壤剖面和来自贵州省喀斯特区赤坭集水区（CC）的 18 个土壤剖面。测定了土壤特性，包括土壤粒径分布、土壤有机碳（SOC）和土壤有机氮（SON）含量以及土壤 pH 值，并在侵蚀生产力影响计算器（EPIC）模型中估算了 K 因子。与石灰岩土壤相比，花岗岩区的土壤具有粗质地、低 SOC 和 SON 以及强酸性的特点。尽管两个地区的 K 因子范围在 0.009 到 0.018 之间，但由于频繁的土壤团聚作用增强了土壤渗透性，从而降低了土壤的可蚀性，石灰岩土壤中的 K 因子被高估了。主成分分析（PCA）和结构方程模型（SEM）的结果表明：（1）花岗岩区土壤的 K 因子估算主要取决于土壤质地，其中粉土是最重要的因素；（2）而石灰岩土壤的 K 因子主要受土壤有机质（SOM）含量的控制，其他土壤特性，包括土壤 pH 值、粘土和粉土含量，也可以通过影响 SOM 积累间接影响 K 因子的预测。
