Spatial And Temporal Pattern And Classification Of Soil Erosion In Lankao County

Mastering and understanding the status quo of soil erosion and its temporal and spatial distribution pattern is of great significance to the planning and management of soil and water conservation and the improvement of the ecological environment.This paper selects Lankao County in Henan Province as the main research object,guided by the theory of soil and water conservation,and remote sensing data such as GF-1,MODIS/NDVI,and SMAP Level 3 as the main information source.Using remote sensing monitoring technology and field survey verification method,using wind erosion model and CSLE model combined with Arc GIS platform to study the temporal and spatial distribution of soil erosion pattern in the study area and the division of soil erosion type areas,with a view to optimizing soil erosion calculation methods for water and soil Provide scientific basis for conservation planning and regional water and soil conservation management.The main research results and conclusions are as follows:1.Temporal and spatial characteristics of soil erosion factors(1)Wind erosion factor:Wind factor: In terms of time,the pattern of "M" increase and decrease changes throughout the year,reaching the highest value in March.In terms of space,the overall trend is gradually decreasing from east to west.Topsoil humidity factor: In terms of time,there is an alternating pattern of increase and decrease throughout the year,reaching its highest value in August.In terms of space,regional changes are obvious,and the overall performance is a gradual decrease from east to west.Surface roughness factor: In terms of time,the overall trend is "single-peak",reaching the annual maximum in August and September.Spatially,because the surface roughness is obtained by assigning values,it is mainly distributed in cultivated land.Vegetation factor: In terms of time,the average value of vegetation factors of forests,gardens and grasses shows a "single-peak" pattern throughout the year,reaching the annual maximum in July.The average value of the county’s vegetation factors showed a "single peak" trend,reaching the maximum in July.Spatially,vegetation factors show a trend of uniform distribution.(2)Water erosion factorRainfall erosivity factor: In terms of time,July to September is relatively strong,and other months are relatively weak.In terms of space,the overall trend is gradually decreasing from southeast to northwest.Soil erodibility factor: spatially,the overall trend is relatively high in the south and north,and relatively low in the east,west and central.Slope and length factor: The slope factor is relatively large in the southwest and northeast as a whole,and the S value in the rest of the region is relatively small.The slope length factor is relatively large in the southern region as a whole,while the remaining regions are relatively small.2.Characteristic pattern of soil erosion patternWind erosion: The total area of wind erosion in Lankao County is 160.00km~2,accounting for14.34% of the total land area,and the erosion intensity is mainly mild.In terms of time,erosion occurred from January to May and November.Spatially,wind erosion is widely distributed.It is distributed in patches near the edge of the Yellow River in the northwest,in the south of Chengguan Township,in the south of Yifeng Township,and near the border between Zhangjun Tomb Town and Xuhe Township and Xiaosong Township.The main types of erosion are Occurs on the ground irrigated by water.Water erosion: The total area of water erosion in Lankao County is 5.43km~2,accounting for0.49% of the total land area,and the erosion intensity is mainly mild.In terms of time,hydraulic erosion mainly occurs from April to September throughout the year.Spatially,hydraulic erosion is relatively scattered,mainly near the concentrated production and construction projects in the south of Dongbatou Township,in the middle of Guying Town,southeast of Chengguan Township,and near the mining area in the north of Nanzhang Town.Eroded land mainly occurs on mining land.3.Classification of erosion typesBased on the wind and water superimposed erosion grid and land use plots,according to the principle and basis of the division,combined with the characteristics of soil erosion plots and the boundaries of administrative divisions,Lankao County is divided into three types of erosion areas:wind erosion area,water erosion area and fengshui compound Erosion zone.The total area of wind erosion area is 578.06 km~2,accounting for 51.80% of the total land area;the water erosion area is 531.53 km~2,accounting for 47.63% of the total land area;the composite erosion area of wind and water is 6.41 km~2,accounting for 0.57% of the total land area.The wind erosion areas are mainly distributed in Sanyizhai Township-Chengguan Township-Yifeng Township-Putaojia Township-Zhangjun Tomb Town-Xuhe Township Area and Dongbatou Township-Guying Town Area and Zhuoying Township-Xuyang Town-Meng Zhaixiang-Nanzhang Town area;water erosion areas are distributed in Chengguan Township-Dongbatou Township-Zhaoying Township Guying Town Area,Hongmiao Town-Yanlou Township-Xiaosong Township-Nanzhang Town Area and the southwest of Zhangjun’s Tomb Town Fengshui compound erosion areas are all mining land,distributed in the northwest of Xuhe Township,the north of Nanzhang Town,the northeast of Hongmiao Town,the south of Dongbatou Township,and the southeast of Chengguan Township.