| The Qinghai-Tibet Plateau is the highest and most complicated plateau in the world.It has unique landforms and natural geographical features.It is also the main source of many rivers in China.Hydrological and climatic characteristics will have a significant impact on global climate change.In recent years,with the gradual warming of the global climate,the permafrost in the Qinghai-Tibet Plateau has also shown a trend of degradation as a whole,causing the ecological environment of the Qinghai-Tibet Plateau to have changed significantly,and it has become one of the areas where the ecological environment of China has been seriously degraded.However,due to inconvenient transportation and extreme climatic conditions in the Qinghai-Tibet Plateau,it is difficult to collect soil and vegetation data in the inaccessible plateau hinterland,so there is little basic information required for existing soil and vegetation models.Soil texture is the most basic physical attribute of soil,and it is also an important input parameter for land surface process models,hydrological models,and atmospheric models coupled with land surface processes.At present,studies on soil particle composition in permafrost regions of the Qinghai-Tibet Plateau have been reported,but little research has been done on the distribution pattern of soil texture profiles.In addition,because the profile distribution pattern of soil texture may be complex and diverse,and it is difficult to predict quantitatively,the profile distribution pattern of soil particle composition on the Qinghai-Tibet Plateau and its relationship with environmental factors are unclear.This paper selects the typical areas in the eastern and western Qinghai-Tibet Plateau,and based on soil data obtained from the background survey of permafrost in the Qinghai-Tibet Plateau,the Wenquan area in the eastern Qinghai-Tibet Plateau,the Budongquan-Qingshuihe area,and the western Kunlun area and Gaize area According to the remote sensing data,a random forest model is used to explore the main controlling environmental factors of each distribution mode.The main research results of the paper are as follows:(1)The content of soil sand in the Wenquan area of the Qinghai-Tibet Plateau is the largest,accounting for more than 80% of the total content,but the coefficient of variation of the clay is the largest.The profile distribution model of clay content in the Wenquan area can be divided into four types: decreasing type,increasing first then decreasing type,decreasing first then increasing type and irregular type.Overall,the topographic and climatic factors are the decisive factors affecting the soil clay profile distribution pattern in the Wenquan area of the Tibetan Plateau.(2)The content of soil silt in the Budongquan-Qingshuihe region of the Qinghai-Tibet Plateau is the largest,accounting for more than 75% of the total content,but the coefficient of variation of the sand is the largest;the profile distribution pattern of the sand content in the Budongquan-Qingshuihe region can be divided into five types: increasing type,decreasing type,increasing first then decreasing type,decreasing first then increasing type and irregular type.topographical factors are the decisive factors affecting the distribution pattern of soil sand in the Budongquan-Qingshuihe area of the Qinghai-Tibet Plateau.(3)The content of sand in the western Kunlun region of the Qinghai-Tibet Plateau is the largest,accounting for more than 85% of the total content,but the coefficient of variation of the clay is the largest.There are five types: increasing type,decreasing type,decreasing first then increasing type,increasing first then decreasing type and irregular type.Topographical and climatic factors are the decisive factors affecting the distribution pattern of soil clay profiles in the western Kunlun area of the Qinghai-Tibet Plateau.(4)The soil sand content in the Gaize region of the Qinghai-Tibet Plateau is the largest,accounting for more than 90% of the total content,but the coefficient of variation of the silt is the largest.The profile distribution pattern of the silt content in the region can be divided into four types: increasing type,increasing first then decreasing type,decreasing first then increasing type and irregular type.Topographical factors are the decisive factors affecting the distribution pattern of soil silt profile in this region.(5)The soil in the permafrost region of the Qinghai-Tibet Plateau has the largest sand content,which accounts for more than 60% of the total content,but the coefficient of variation of the silt is the largest;the profile distribution pattern of soil silt content in the permafrost region of the Qinghai-Tibet Plateau can be divided into five types: increasing type,decreasing type,increasing first then decreasing type,decreasing first then increasing type and irregular type.Topographic and climatic factors are the decisive factors affecting the distribution pattern of soil silt profiles in the permafrost regions of the Tibetan Plateau.(6)There are obvious differences in topography and climate between the east and west of the permafrost region on the Qinghai-Tibet Plateau.The distribution patterns of soil texture profiles and their influencing factors have both differences and some similarities.Due to the differences in the types and climate of the mother rocks in the Wenquan area of the eastern Qinghai-Tibet Plateau and the Budongquan-Qingshuihe area,there is a large difference in the content of soil texture composition.Overall,topographic factors are the main environmental factors that affect the distribution pattern of soil texture profiles in the eastern Tibetan Plateau.The climate in the western Qinghai-Tibet Plateau is extremely arid and cold.The mother soils in the West Kunlun and Gaize regions are mainly Quaternary,so their soil texture and composition are similar.Topography and climatic factors are the main environmental factors that affect the distribution pattern of soil texture profiles in the western Tibetan Plateau. |
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