Soil Pedogenesis And Environmental Significance Based On Aeolian Parent Materials In Western Sichuan

Under the influence of environment,soil is constantly evolving and its physical,chemical and biological properties are changing.Different environmental factors have different strength and manner effects on soil.Studying the relationship between pedogenesis and environment is helpful to understand the intensity and mode of environmental factors to soil action,to find the determinants affecting soil pedogenesis,and to reveal the influence of environment on pedogenesis.At present,the studies on the quaternary aeolian sediments in China mainly focuses on their causes and sources,but lacks the properties of pedogenesis and the research of regional comparison.Therefore,Therefore,this study took the soil developed on loess of the upper Minjiang and Chengdu Clay as the research object,and compared the characteristics of soil color,particle composition,magnetic susceptibility,organic matter,calcium carbonate and a series of geochemical parameters.In addition,combining with the pedogenesis of soil developed on aeolian sediments in other regions,the differences and causes of genetic characteristics of soil developed on aeolian sediments in different regions were explored,and the pedogenesis properties sensitive to environmental response were found to establish the quantitative relationship between environmental sensitive indexes and climatic factors.The main results are as follows:?1?The pedogenesis properties of soil developed on the loess in the upper Minjiang showed that the color of surface soil is darker than that of other layers,and the content of clay and organic matter shows phenotypic polymerization.Soil magnetic susceptibility are affected by land use types.Soil CaCO₃,organic matter,CaO and geochemical parameters all show spatial differentiation on elevation gradient,which indicates that soil in high altitude area has a stronger chemical weathering degree.?2?The pedogenesis properties of soil developed on Chengdu Clay show that the surface soil has the darkest color,and the sand and organic matter content are all surface-polymerized.Soil magnetic susceptibility organic matter content,and geochemical parameters indicate that soil development is related to land use type.The soil pedogenesis properties of forest indicate that it has a stronger chemical weathering degree.?3?Comparison of the pedogenesis properties of soil developed on the loess in the upper Minjiang and Chengdu Clay showed that the CIA,Ba/Sr,Rb/Sr and residual coefficient of soil in Chengdu Clay are higher,while magnetic susceptibility,CaCO3,pH,leaching coefficient and alkali coefficient are lower.It is indicated that the soil developed on Chengdu Clay has a stronger chemical weathering degree,which implies the warm and humid climatic characteristics of Chengdu Plain.The soil developed on the loess in the upper Minjiang has lower CIA,Ba/Sr,Rb/Sr,residual coefficient,higher magnetic susceptibility,CaCO_3,pH,leaching coefficient and degeneration coefficient,which indicates that the soil developed on the loess in the upper Minjiang is weaker,suggested the climatic characteristics the climatic characteristics of the upper Minjiang relative to dry and cold.?4?Comparing the pedogenesis properties of western Sichuan and other regional,it is found that the particle size composition,element composition characteristics of aeolian sediments in different regions are highly consistent,indicating the same sedimentary basis,but the degree of pedogenesis experienced by them is obviously different,which is manifested as Xiashu Loess>Chengdu Clay>Hanjiang loess>Loess of Loess Plateau>Minjiang Loess.In space,the pedogenesis trend of the developing soil on the aeolian sediment decreases from the southeast to the northwest,which is same as the spatial difference of the monsoon climate in China.Among them,the chemical weathering degree of soil in the upper Minjiang and Loess Plateau are close,and the chemical weathering degree and direction of the soil developed in Chengdu Clay,Xiashu loess and Hanjiang loess are close.?5?By means of correlation analysis and regression analysis,the CaCO₃,magnetic susceptibility and CIA are selected as the precipitation sensitive indexes,and magnetic susceptibility can also be used as a temperature-sensitive index to establish the quantitative relationship between the occurrence index and the climatic elements.?6?Pedogenesis properties of the soil on the loess in the upper Minjiang reflect the spatial difference,and the soils pedogenesis in the high-altitude soils are stronger.The pedogenesis properties of the soil in Chengdu reflect soil pedogenesis is affected by the land use pattern,and the woodland soil has the strongest pedogenesis.The pedogenesis of Chengdu Clay development soil is generally stronger than that of loess-developed soil in the upper Minjiang,indicating that the climate of Chengdu is warm and humid,with more precipitation.The loess developed in the upper Minjiang has dry climate and less precipitation.The chemical weathering degree of the developed soil on the aeolian sediments in western Sichuan and other regions is significantly different,and it is consistent with the spatial difference of monsoon climate in China,indicating that regional climatic conditions?precipitation and temperature?have significant effects on soil genetic characteristics.The values of calcium carbonate and CIA are affected by precipitation,and the magnetic susceptibility is affected by precipitation and temperature,but the susceptibility is more sensitive to temperature.