Study On Physical-Specific Properties Of Vertisols In Fujian Province

Vertisols developed on the weathering products of the basalt, distributed over hilly land and terraces along Fujian coast have been distinguished into the lateritic red earths. Their properties are obviously different. Vertisols properties、soil fertility、agricultural production characters such as nutrient status, soil adsorption, moisture capacity, tillage, cropping system, fertilization effect, irrigation measures and crop yield and quality have many reports and the related achievements come out, but it promulgated the soil particle composed structure、swelling and shrinkage、development of reticular cracks and the mechanism of soil surface crust basically in traditional research, obviously these traditional research straightened up constrained by the method as well as past experimental method relative backwandness cannot satisfy the soil science development.In this paper, Vertisols distribution area、soil-forming conditions and process、 physicochemical properties and agricultural production characteristics are summarized in Fujian. By comparison with the lateritic red soils, there are difference in use and management. Secondly, compared Vertisols and other engineering regional soils, we study on Vertisols with the achievements of engineering mechanics, it can provide more availability for further research on the soils. Vertisols fracture formation mechanisms were explored, it can be concluded that swelling-shrinkage cause Vertisols fracture formation. We clarified the swelling-shrinkage characteristics by special devices.Compared the swelling-shrinking characteristic of Vertisols and lateritic red soils, it was analyzed not only the relationship between the Vertisols sample’s altitude and time in the course of swelling-shrinkage but also the mechanisms of soil surface crust. Thirdly, we used the fractal theory which has the unique superior to the complex system to analyze soil particle composition pellet fractal and the cracks fractal characteristics. It is described the characteristics of the soil texture by the fractal dimension of soil particle-size, in addition the fractal dimension of soil particle-size is a proof of new generation of montmorillonite process. The result shows that negative correlation between the fractal dimension of soil particle-size distribution characteristics and uniformity coefficient (Cu). It shows that fractal dimension of soil particle-size distribution is affected (except clay content dominate) by distribution of particle fractions. Fourthly, Test on disturbed Vertisols fracture’s occurrence and development law, there exist differential fracture shape of disturbed and undisturbed Vertisols, and further research on fracture mechanisms were put forward. It was found that not only raindrop colliding and shock which damages and compacts soil aggregate but also soil particle composition clay mineralogical composition had influence on the formation of surface crust. Soil fine particle realigns crust by transporting to fill stomata with water transformation.The results made some supplements to new generation and crust formation in some aspects.The calculated Vertisols cracks fractal dimension is the fundamentary for the cracked soil permeability by MATLAB. Finally, we investigated the experiments in field runoff lots compared the Vertisols slopes that with and without sandy. This paper assessed systematically the slope process characteristics of erosion and sediment, disclosed the effections of soil surface crust on Vertisols slopes and crops grown. Applies the theory and the anlysis method are without doubt may make a broader region the promotion, this article findings have disclosed the physical-specific properties of Vertisols.