Forest Soil Genetic Properties And Taxonomy On The Northern Slope Of Middle Tianshan

The northern slope of middle tianshan is taken as sample area. The soil genetic properties and soil taxonomy are studied on basis of field survey and analysis physical and chemical properties of soil on the northern slope of middle tianshan are performed by Chinese Soil Taxonomy (CST).The research results are listed as follows:The results of soil morphological character's research show that:soil thickness is increasing as the increased of altitude. While it decreasing as the increased of altitude after it reaches the maximum at the 1900m altitude. The reasons are that:on the on hand, there is the loess parent material in the sample, an the other hand, the soil is accumulated on the slope. The results of soil mechanical composition show that:Soil texture is gradually refined as the increased of altitude and the soil mechanical composition is composed mainly by sand pebble, silt particle and clay particle. The results of studied on soil micromorphological character in this sample show that:In the lower part of this sample:The soil structures main are sandy single grain micro-structure, and there is little plant residue in the upper soil layer, there is not optically oriented clays in B layer, so that there is not clay moment and clay particle in B layer. The soil bones particles taking quartz and feldspar as main. The soil has a lower developed degree. In the middle part of this sample:Soil micro-structure taking aggregate micro-structure as main. There are many plant residues, dark color humus and dark color animal excrement in soil. The soil bones particles taking quartz and feldspar as main. There is optically oriented clays in B layer, so that there is clay moment and clay particle in B layer. The soil developed well and the diameters of the mineral particles are shorter. In the upper part of this area:Soil micro-structure taking aggregate micro-structure as main. There are visible plant residues, dark color humus in both soil upper layer and middle layer. The reasons are that:The plant coverage on ground is higher and there is source of soil humus. But the decomposed speed of humus is slowly because of the lower temperature at the high altitude. There is not optically oriented clay in B layer, so that there is not clay moment and clay particle in B layer.The results of soil physical chemical properties research show that:In the lower part of this sample: there is not much soil organic matter because there is a low plant coverage degree on ground and there is little of source of soil humus, and the speed of soil organic matter is quick in the dry and hot climate. In the middle part and upper part on this sample:there is much soil organic matter because of that:The plant coverage on ground is higher and there is source of soil humus. But the decomposed speed of humus is slowly because of the lower temperature at the high altitude. The results of soil mineral total elements research show that:Si taking the main position in the soil mineral total elements, and 80% of the mineral total element is Si, Al and Fe. Si of soil is decreasing as the increased of soil depth. It doesn't accord with general rule. The reasons are maybe that:the soil parent material layers are homogeneous because of the slope product parent material and pluvial parent material and there is gravel layer in the lower part of soil. The soil Al and Fe are almost not changed as the increased of soil depth. In the middle part and upper part of this sample:there is a certain weathering in the upper layer of soil because the Si is increasing as the increased of soil depth. There is a certain leaching in a micro acid environment because the A1 and Fe is increasing as the increased of soil depth. The results of other soil physical chemical properties research show that:there is a partial alkaline environment and a high calcium carbonate content and a low cation exchange capacity content in the lower part of this sample and the soil base saturation is saturated. There is a partial acid environment and a low calcium carbonate content and a low cation exchange capacity content in the middle part of this sample and the soil base saturation is unsaturated. There is a partial alkaline environment and a low cation exchange capacity content in the upper part of this sample and the soil base saturation is saturated and there is non calcium carbonate.The soil of sample was divided into four soil ordesr are Aridisols, Entisols, Luvisols and Isohumsols on basis of field survey and analysis physical and chemical properties of soil by Chinese Soil Taxonomy. The soil was further divided into five soil suborders are Orthic Aridisols, Alluvic Entisols, Orthic Entisols, Ustic Luvisols and Udic Isohumisols, five soil groups are Hap-Orthic Aridisols, Ust-Alluvic Entisols, Ust-Orthic Entisols, Hap-Ustic Luvisols and Hap-Udic Isohumisols, five soil subgroups are Lit-Hap-Orthic Aridisols, Lit-Ust-Alluvic Entisols, Typ-Ust-Orthic Entisols, Typ-Hap-Ustic Luvisols andTyp-Hap-Udic Isohumisols. And the soil altitudinal zonation was established on basis of the CST.