Soil erodibility(K) is a key factor of soil erosion, and its appropriate quantification and interpolation are vitally important for soil and water conservation.The traditional point-represent-polygon approaches and common kriging method for the estimation of K, however, do not sufficiently represent the original data. The objectives of this study were to simulate the spatial distribution of K using a sequential Gaussian algorithm and analyze the uncertainty in evaluating the risk of soil erodibility in southeastern China. We determined 101 sampling points in the area and collected disturbed soil samples from the 0–20 cm layer at each point. Soil properties were determined, and K was calculated using five common models: the EPIC(Erosion/Productivity Impact Calculator),approximate nomograph, Torri, Shirazi, and Wang models. Among the chosen models, the EPIC model performed the best at estimating K(KEPIC), which ranged from 0.019 to 0.060 t ha h(ha MJ mm)~(-1), with a mean of 0.043 t ha h(ha MJ mm)~(-1). The KEPICwas moderately spatially variable and had a limited spatial structure, increasing from south to north in our study area, and all spatial simulations using the cooperative kriging(CK) interpolation and the sequential Gaussian simulation(SGS) with 10, 25, 50, 100, 200, and 500 realizations had acceptable accuracies. The CK interpolation narrowed the range,and the SGS maintained the original characteristics of the calculated data. The proportions of the risk area were 38.0% and 10.1%, when the risk probability for K was 60% and 80%, respectively, and high risk areas were mostly located in the north. The results provide scientific guidance for managing the risk of soil erodibility in southeastern China. 相似文献
The aims of this study were to investigate the composition of clay minerals in soils derived from different parent materials and to elucidate how parent materials and pedogenic environment affect the distribution of clay minerals and reveal the implications for pedogenetics and taxonomy in Stagnic Anthrosols.
Materials and methods
Clay mineralogy and physicochemical properties of the Hydragric horizon of Stagnic Anthrosols derived from granite (GR), plate shale (PS), quaternary red clays (QRC), limestone (LS), purple sandy shale (PSS) and fluvial-lacustrine deposit (FLD) located in Hunan Province of China were analysed to explore the relationships between the conditions influencing the formation of the soil and the composition of clay minerals.
Results and discussion
Results indicated that the composition of clay minerals is closely related to both parent material and type of Stagnic Anthrosols: the soils derived from GR, PS and QRC, which are mostly classified as Fe-accumulic-Stagnic Anthrosols, are dominantly 1:1 type kaolinite and vermiculite and illite/vermiculite mixed layer minerals of widespread distribution. However, soils derived from LS, PSS and FLD were mainly classified as Hapli-Stagnic Anthrosols and are mainly composed of 2:1 type illite/smectite mixed layer minerals, where chlorite is commonly found. Illite is widely distributed and its content varies the least among different parent materials. An extremely significant relationship between pH and kaolinite, chlorite and mixed layer minerals was noted, and the two kinds of mixed layer minerals showed highly significant negative correlation.
Conclusions
This study revealed that the types and quantities of clay minerals in the soil are closely related to the types of parent material. This reflected better direction and degree of development in Stagnic Anthrosols, which is related to the physicochemical properties of parent material and can be used as one of the bases for the classification of soil groups and subgroups within the soil family for Stagnic Anthrosols in Chinese Soil Taxonomy.
Journal of Soils and Sediments - Phytolith-occluded carbon (PhytOC) is mainly derived from the products of photosynthesis, which can be preserved in soils and sediments for hundreds-to-thousands of... 相似文献