| Soil erosion is affected and restricted by a variety of factors and has significant regional heterogeneity in spatial distribution.The study of soil erosion under the combined action of natural factors and human activities is great importance to the prevention and control of regional water and soil loss.The north slope of Tianshan Mountain is not only the focs of Xinjiang’s economic,scientific,technological and social development,but also the region with the greatest development potential.The special topography and arid climatic conditions determine the fragile ecological environment on the northern slope of the Tianshan Mountains.With economic development and resource development,the constraints and protection of the water and soil resource environment have become one of the main factors that restrict regional economic and social development.There are still no systematic quantitative studies on the differentiation characteristics of soil erosion areas and the layout of prevention and control.This paper takes the Fukang City which is on the northern slope of the Tianshan Mountains as a research area.Through the methods of geostatistical analysis,model calculation and spatial overlay analysis,this paper analyzes the regional differentiation characteristics of soil erosion and influencing factors in Fukang City on the northern slope of Tianshan Mountain,and studies the layout of the soil and water conservation area,combined with the needs of social and economic development and soil and water conservation,delineated the key areas and targets of soil erosion control,in order to provide basic data and technical support for soil erosion prevention in the eastern section of the northern slope of the Tianshan Mountains,and also provide science basis for the construction of soil and water conservation ecological environment in Xinjiang.The main research results are as follows:(1)The spatial differentiation of the main influencing factors of soil erosion is significant.The landscape is dominated by hills and terraces,accounting for 75.95%,forming the landscape pattern of southern mountains and hills,central oasis plain and northern desert hills.Slope with gentle slope(<5°)is given priority to,accounting for 71.53%,Southern mountain slope is given priority to with 8-35°slope,accounted for 68.86%,and the slope as the altitude rises;And about 91.58%of the central plain with<5°.Northern desert area with<8°is given priority to,accounting for 97.23%.The annual average rainfall decreased from south to north,and the highest in the southern mountainous area was 572mm,while the northern desert area was less than 100mm.The annual average wind speed decreased from south to north,the highest in the southern mountainous area was 3m/s,and the highest in the northern desert area was less than 2m/s.The soil type is mainly aeolian desert soil,accounting for 50.55%.The vertical differentiation of soil type is obvious in the southern mountainous area.The elevation is distributed from low to high in order:brown calcium soil,chestnut soil,gray brown soil,subalpine meadow soil,alpine meadow soil and alpine desert soil.The soil moisture is between 0and 60%,decreasing from south to north.The soil moisture in the southern mountainous area is between 5 and 60%.The soil moisture increases with the elevation.The soil moisture in the central plain is between 5-25%.The overall soil moisture in the northern desert is below 5%.The average annual vegetation coverage is mainly medium and low(30-45%),accounting for 67.03%.The southern mountainous area has prominent vertical zonal characteristics.The alpine subalpine meadow and lowland grassland are dominated by low coverage(15-30%),while the zhongshan forest belt is dominated by high coverage(>75%).The central plain area is composed of alluvial fan grassland,plain plantation forest and desert grassland.The northern desert area is a desert steppe dominated by middle and low coverage.Grassland was the main land use,accounting for 77.14%,followed by cultivated land and woodland,accounting for 10.76%and 4.3%,respectively.The main land use in the southern mountainous areas was grassland and woodland,accounting for 77.61%and 16.03%respectively.The central plain is mainly grassland and cultivated land,accounting for 42.21%and 37.36%respectively.The northern desert area is mainly grassland,accounting for 96.45%.Human activities mainly involve oil and gas,mineral resources development,agriculture and animal husbandry production and urban construction.The central plain is dominated by urban construction and agricultural production.The northern desert is dominated by oil and gas production.(2)The regional soil erosion intensity is mainly mild and the spatial differentiation is obvious.The area of soil erosion is 7652.79km~2,accounting for 94.59%of the land area.The average regional soil erosion modulus is 1331t/(km~2·a).In the area of soil erosion,mild erosion accounts for 86.99%,while moderate,strong,extremely strong and severe erosion accounts for7.84%,2.40%,1.81%and 0.96%respectively.Soil erosion was mainly mild erosion,and the proportion of soil erosion intensity decreased with the increase of soil erosion grade.The spatial differentiation of soil erosion presents obvious zonality of north-south gradient,from wind erosion in the northern desert area to geomantic complex erosion in the central plain,and then to water erosion and freeze-thaw erosion in the southern mountainous area.The northern desert was dominated by slight wind erosion,accounting for 97.66%.Moderate and above wind erosion was concentrated in the flow,semi-fixed sand dunes and the vicinity of oil and gas fields in the northeast corner of the study area.The central plain was dominated by mild composite erosion,accounting for 72.49%.Strong and above erosion is distributed in the front alluvial fan area.The southern hilly area was dominated by slight water erosion,accounting for50.59%.Strong and above water erosion is concentrated in overgrazing and mining areas.On the whole,soil erosion intensity is lower in the middle and high mountain areas with high forest and grass coverage in the south,while soil erosion intensity is higher in the plain areas where human activities are relatively concentrated,on both sides of rivers and gullies,in the hilly areas and desert oil and gas fields.Thus it can be seen that natural factors are the prerequisite for the regional differentiation of soil erosion,and the difference of human activities further aggravates the regional differentiation of soil erosion.(3)To conduct research on the distribution of soil and water conservation areas and delimit the scope of key prevention and control.According to the regional differentiation characteristics of soil erosion and its influencing factors,combined with the analysis of basic functions of soil and water conservation,the study area is divided into three areas:windbreak and sand-fixing area in the northern desert,farmland protection and settlement environment protection area in the central plain,and water conservation and ecological protection area in the southern mountain.Based on high-resolution remote sensing,field investigation,characteristics of human activities and ecological environment construction needs of soil and water conservation,this paper puts forward the division index of the scope and objects of key prevention and control,and delimit the scope and objects of key prevention and control,and the area of key prevention and control is 1880.90km~2.Among them,there are 3 key prevention areas,and the prevention area is 1361.82km~2,involving 11 key prevention objects,mainly concentrated in the forest and grassland area on the north slope of tianshan mountain,the central reservoir and salinization area,the northern desert irrigation canal and the areas on both sides of the road.The key treatment area is 519.08km~2,involving four key treatment objects,mainly concentrated in the interlaced area of plain and desert,plain and mountain,the concentrated distribution area of mineral resources and the two sides of river channel. |
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