Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin, Heilongjiang 150081, PR China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Water and Soil Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, PR China.
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Water and Soil Conservation, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
Sci Total Environ. 2021 Jun 10;772:145540. doi: 10.1016/j.scitotenv.2021.145540. Epub 2021 Feb 3.
Soil erodibility is an indispensable parameter for predicting soil erosion and evaluating the benefits of soil and water conservation. Slope situation can alter revegetation and its effects on soil properties and root traits, and thus may affect soil erodibility. However, whether slope situation will change the effect of revegetation on soil erodibility through improving soil properties and root traits has rarely been evaluated. Therefore, this study was conducted to detect the response of soil erodibility to slope situations (loess-tableland, hill-slope and gully-slope) in a typical watershed of the Loess Plateau. Five soil erodibility parameters (saturated soil hydraulic conductivity, SHC; mean weight diameter of aggregates, MWD; clay ratio, CR; soil disintegration rate, SDR; soil erodibility factor, K) and a comprehensive soil erodibility index (CSEI) are selected to clarify the study targets. The results revealed that soil properties, root traits, soil erodibility parameters and CSEI were affected by slope situation significantly. Soil and root can explain 79.7%, 79.1% and 69.8% of total variance in soil erodibility of loess-tableland, hill-slope and gully-slope, respectively. Slope situation influenced soil erodibility by changing the effects of revegetation on soil properties and root traits. Evidently, the slope situation greatly changed the relations between CSEI and soil and root parameters, whereafter a model considering slope situation (slope steepness), sand, organic matter content and root surface area density was reliable to estimate soil erodibility (CSEI). Our study suggested that the Armeniaca sibirica, the combination of Bothriochloa ischcemum and Robinia pseudoacacia and the combination of Armeniaca sibirica and Lespedeza bicolor can be used as the optimal selection for mitigating soil erodibility of loess-tableland, hill-slope and gully-slope, respectively. This study is of great significance in optimizing the spatial layout of soil and water conservation measures for different slope situations of the Loess Plateau.
土壤可蚀性是预测土壤侵蚀和评估水土保持效益的不可或缺的参数。坡度情况会改变植被恢复及其对土壤性质和根系特征的影响，从而可能影响土壤可蚀性。然而，坡度情况是否会通过改善土壤性质和根系特征来改变植被恢复对土壤可蚀性的影响，这很少得到评估。因此，本研究旨在检测黄土高原典型流域不同坡度（黄土塬、坡地和沟坡）情况下土壤可蚀性对植被恢复的响应。选择五个土壤可蚀性参数（饱和土壤水力导率、MWD；粘粒比、CR；土壤崩解率、SDR；土壤可蚀性因子、K）和一个综合土壤可蚀性指数（CSEI）来阐明研究目标。结果表明，土壤性质、根系特征、土壤可蚀性参数和 CSEI 受到坡度情况的显著影响。土壤和根系分别可以解释黄土塬、坡地和沟坡土壤可蚀性总方差的 79.7%、79.1%和 69.8%。坡度情况通过改变植被恢复对土壤性质和根系特征的影响来影响土壤可蚀性。显然，坡度情况极大地改变了 CSEI 与土壤和根系参数之间的关系，因此，考虑到坡度情况（坡度陡峭度）、沙、有机质含量和根表面密度的模型更可靠地估计土壤可蚀性（CSEI）。我们的研究表明，在黄土塬、坡地和沟坡上，分别可以选择沙棘、芨芨草和刺槐、沙棘和胡枝子作为减缓土壤可蚀性的最佳选择。本研究对于优化黄土高原不同坡度的水土保持措施的空间布局具有重要意义。
