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195 results on '"Wei, Chaofu"'

15. Distribution Characteristics of Soil Heavy Metals, their Source Identification and their Changes Influenced by Anthropogenic Cultivation Activities in Purple Hilly Regions of Sichuan Basin, China

Author

Du, Jing, Wang, Zhengkui, Liu, Juan, Zhong, Shouqin, and Wei, Chaofu

Abstract

To investigate the distribution and, possible sources of soil heavy metals and the effects of anthropogenic cultivation activities on the contents of these metals in purple hilly regions of China, samples of soils and parent materials in purple hilly regions of China were collected before and after land consolidation and after 7 and 19 months of intensive agricultural production, and contents of Pb, Cd, Cu, Zn, Cr, Ni, Hg, and As were analyzed. The results showed that, in the soil samples compared with the parent materials, the greatest accumulation of Cd, As, and Hg occurred in surface layer and a few other horizons. Furthermore, the Cd and Hg contents showed the largest differences among different soil horizons. Parent materials played an important role and anthropogenic cultivation activities greatly affected the soil heavy metals. Under traditional agriculture, Pb, Cd, and Hg had higher contents in surface paddy soils than in surface dry land soils. Land consolidation induced the homogenization of heavy metal elements and dramatically reduced Cd and Hg in the surface soils. The As and Hg contents in the surface soils increased after 19 months of intensive agricultural production. Multivariate statistical analysis (correlation analysis and principal component analysis (PCA)) showed that all eight metals were well represented by the first two principal components (PCs). PC1, which showed relatively high loadings for Cr, Zn, Cu, Ni, and As, was associated with parent materials and therefore represented natural sources. PC2 showed relatively high loadings for Pb, Cd, and Hg, reflecting the effect of air pollution under traditional agriculture, and showed relatively high loadings for Cd, Hg, As, and Pb, reflecting the effect of fertilization under intensive agriculture. This study provides guidelines for the prevention of soil heavy metal pollution and the remediation of polluted soils in purple hilly regions of Sichuan Basin, China.

Published
2024
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18. How do Microtopography Act in the Pedogenic Characteristics of Mudstone-derived Soils in Hilly Mountainous Regions?

Author

Luo, Banglin, Li, Jiangwen, Tang, Jiahong, Wei, Chaofu, and Zhong, Shouqin

Abstract

The topography is a critical factor that determines the characteristics of regional soil formation. Small-scale topographic changes are defined as microtopographies. As a characteristic topographic condition in hilly mountainous regions, the redistribution of water and soil materials caused by microtopography is the main factor affecting the spatial heterogeneity of soil and the utilization of land resources. In this study, the influence of microtopography on pedogenesis was investigated using soil samples formed from mudstones with lacustrine facies deposition in the middle of the Sichuan Basin and developed into hill landforms by erosion of flowing water. Soil profiles were sampled along the slopes at the summit, shoulder, backslope, footslope, and toeslope positions. The morphological, physiochemical, and geochemical attributes of profiles were analysed. The results showed that the soil thickness increased significantly with changes in the soil profile configuration from the summit to the toeslope, and the profile configuration changed from A-C to A-B-C. The migration direction of Ca and Na at the summit, backslope, and footslope changed from enrichment to leaching, whereas that of Al, Fe, and Mg changed from leaching to enrichment. At the summit and shoulder of the hillslope, weathered materials are transported away by gravity and surface erosion, and new rocks are often exposed; therefore, the characteristics of soil development is relatively weak. However, in flat areas such as the footslope and toeslope with sufficient water conditions, the long-term contact between water, soil, and sediment leads to further chemical weathering, resulting in highly developed characteristics. Microtopography can affect physicochemical properties, chemical weathering, and redistribution of water and materials, resulting in differences in pedogenic characteristics at different slope positions.

Published
2023

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