Grain structure and nutrient degradation characteristics of soil from small watershed’s sloping lands in Yimeng mountainous areas
Shan Guimei, Zhang Chunping, Liu Wudi, Zhang Guangcan, Yao Xiaoyou, Yang Shaoyang, Wang Jing
（1.Shandong Provincial Key Laboratory of Soil Erosion and Ecological Restoration, Department of Soil and Water Conservation, Shandong Agricultural University, Taishan Forest Ecosystem Research Station of State Forestry Administration, 271018, Tai’an, Shandong, China;
2.Monitoring Center Station of Soil and Water Conservation, Huaihe River Commission, Ministry of Water Resources, 233001, Bengbu, Anhui, China）
Abstract：In order to explore the relationship between soil degradation and slope gradient of arable sloping lands, the correlation among soil particle composition, fractal dimension and nutrient content were measured for three land types, i.e., arable sloping lands with different gradients, abandoned arable lands and ecological woodlands, at a typical small watershed in the Yimeng mountainous areas. The results indicated that, 1) for all the three land types, the content of sand was the highest while that of clay was the lowest, with an average of 70.81% and 0.75% respectively; 2) both the fractal dimension of soil particles and organic matter content ranked in a descending order as ecological woodlands > abandoned arable lands > arable sloping lands; 3) the fractal dimension of soil particles declined as the slope gradient increased, showing a highly significantly positive correlation with the silt content and a significantly positive correlation with the clay content; 4) the soil organic matter content was significantly negatively correlated with sand content but significantly positively correlated with the silt and clay contents, while nitrogen, phosphorus and potassium contents had no significant correlations with soil particles content; 5) the soils in the study area were found to have the physical characteristics of coarse texture sand, and the intensified cultivation activity and increased slope gradient of arable sloping lands would aggravate the loss of silt and clay contents, which will further result in the decline of distribution uniformity, fractal dimension, water and fertilizer maintenance capacity as well as nutrient content of soil particles.
2013, Vol. 11 
