Morphologies Characteristics And Driving Factors Of Erosion Gully In The Northern Slope Of Tianshan Mountains

Erosion gully is formed from the surface runoff when slope or elevation change and lacking plant protection, crack point together to form, accounting for important position in the soil and water loss. Soil erosion condition is the important indicators to test environment quality,the space-time change of which will directly or indirectly affect the production development and national economic growth. North slope of Tian Shan mountain has unique topography and geomorphology,climate factors and the impact of human activities, leading to the area of soil and water erosion phenomenon urgently, especially the phenomenon of soil erosion gully. This paper chooses erosion gully on the north slope of Tian Shan mountain foothills as the research object, Using GIS and RS technology combined with field investigation, to research and analyze the area spatial pattern. The results showed that:1 This paper draws the spatial distribution of gully erosion in the study area, which includes 35 shallow ditch and 23 gully through the field investigation to measure gully erosion parameters and the image interpretation of remote sensing to check mutually results. At the same time, 10 typical shallow ditch and 10 gully are chosen to analyze characteristic value. The interpret results indicates that there are four kinds of Land use type in the area, respectively medium coverage grassland, low coverage grassland, desert and bare. Among these, the former two are occupied more than 80% of the total.2 Based on remote sensing and field survey analysis and by constructing a model analysis of typical erosion gully morphological characteristics in the study area,The study found that:First,There is a three certain relationships between characteristic value in this study area typical erosion gully: firstly,they have a very significant positive correlation each other,such as average depth of Shallow groove with the average width,the cross sectional area of Shallow groove with average groove width and average groove depth,shallow gully volume with average groove depth and Cross-sectional area,Shallow gully catchment area with ditch,the cross sectional area of gully with average groove width and average groove depth,gully volume with Cross-sectional area and Gully area.Secondly,they have a significant positive correlation,such as area of shallow gully with ditch,shallow gully volume with gully area and average groove width,shallow gully catchment area with gully area,gully area with ditch,volume of gully with average groove width and average groove depth.Lastly, they have no correlation with others,such as gully length,average trench width and average depth of furrow,the catchment area and characteristic value.Second Typical shallow groove and gully belong to Open and Weak degree separation erosion in the study area.Third,slope is one of the important topography factors to affect farmland soil erosion.The density of shallow groove erosion and gully erosion is positively correlated with slope,the greater the slope leading to the generation and development of erosion gully,the greater the density.Gully length has obvious relation with erosion gully density,which increases as the density changes presenting the trend from rise to decline.3 There are three soil erosion in the study area,respectively strong erosion,moderate erosion and slight erosion.The area of study area is 458.36hm2.Soil erosion area more than mild occupy 158.18 hm2,which is the 34.51 percent of the study area.Shallow groove and gully partly accounts for 39.04% and 60.96% of the proportion of the erosion area. Shallow groove and gully partly accounts for 44.82hm2 and 54.18hm2 of the Low coverage grassland,11.36hm2 and 25.57hm2 of the medium coverage grassland,4.8hm2 and 16.47hm2 of the desert.In addition, bare land is given priority to shallow gully erosion,which occupy 0.99 hm2.The slope of study area locates in 0 ~ 25.52°.Of these,the slope of 0 ~ 5°makes up 84.68 hm2, shallow groove gully erosion respectively account for 21.44 hm2 and 63.24hm2.the slope of 5 ~10 ° makes up 48.59 hm2, shallow groove gully erosion respectively account for 27.50 hm2 and 21.09 hm2.the slope of 10 ~ 15°makes up 13.40 hm2, shallow groove gully erosion respectively account for 7.04 hm2 and 6.37 hm2.the slope of 15 ~ 20° makes up 11.50 hm2, shallow groove gully erosion respectively account for 5.98 hm2 and 5.52 hm2.Erosion gully are mainly distributed in the southwest,the southern and the west slope, being less in other slope.The research results illuminate the area spatial pattern of distribution,which provide a scientific basis for defensing and governing erosion gully.