Luo Banglin, Li Jiangwen, Tang Jiahong, Wei Chaofu, Zhong Shouqin
College of Resources and Environment/Key Laboratory of Eco-Environment in Three Gorges Region (Ministry of Education), Southwest University, No. 2 Tiansheng Road, Beibei District, Chongqing, 400715, People's Republic of China.
District Agro-Tech Extension and Service Center of Shapingba, Chongqing, 400000, China.
Sci Rep. 2024 May 25;14(1):11998. doi: 10.1038/s41598-024-62540-y.
Topography is a critical factor that determines the characteristics of regional soil formation. Small-scale topographic changes are referred to microtopographies. 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. Soil profiles were sampled along the slopes at the summit, shoulder, backslope, footslope, and toeslope positions. The morphological, physicochemical, and geochemical attributes of profiles were analyzed. The results showed that from the summit to the toeslope, soil thickness increased significantly and profile configuration changed from A-C to A-B-C. The total contents of Ca and Na decreased at the summit, backslope, and footslope, while the total contents of Al, Fe and Mg showed an opposite trend. On the summit and shoulder of the hillslope, weathered materials were transported away by gravity and surface erosion, exposing new rocks. As a result, soil development in these areas was relatively weak. In flat areas such as the footslope and toeslope with sufficient water conditions, the addition of weathered components and the prolonged contact between water, soil, and sediment led to further chemical weathering, resulting in highly developed characteristics. Microtopography may influence physicochemical properties, chemical weathering, and redistribution of water and materials, causing variations in pedogenic characteristics at different slope positions.
地形是决定区域土壤形成特征的关键因素。小规模的地形变化被称为微地形。在丘陵山区，微地形引起的水土物质再分配是影响土壤空间异质性和土地资源利用的主要因素。本研究以四川盆地中部湖相沉积泥岩形成的土壤样本为对象，研究了微地形对土壤发生的影响。沿着山顶、山坡肩部、山坡后坡、山坡脚和坡麓位置的坡面采集土壤剖面样本。分析了剖面的形态、理化和地球化学属性。结果表明，从山顶到坡麓，土壤厚度显著增加，剖面构型从A-C变为A-B-C。山顶、后坡和坡脚的Ca和Na总含量降低，而Al、Fe和Mg的总含量则呈现相反趋势。在山坡的山顶和肩部，风化物质被重力和表面侵蚀带走，露出新的岩石。因此，这些区域的土壤发育相对较弱。在坡脚和坡麓等平坦区域，由于水分条件充足，风化成分的增加以及水、土壤和沉积物之间的长时间接触导致了进一步的化学风化，从而形成了高度发育的特征。微地形可能影响理化性质、化学风化以及水和物质的再分配，导致不同坡位土壤发生特征的变化。
