Land Use Changes In Lanzhou New Area Impact On Ecological Environment And Evaluation

In the course of the development of human society,the location of land resources is of utmost importance.People's changes in the use of land have led to the development of social economy on the one hand,and have also had a great impact on the natural ecological environment.The development and construction of Lanzhou New District is of great significance to the economic development of Gansu Province and the northwest region.Moreover,the Lanzhou New District is located in the northwest inland,with low rainfall,dry climate,poor natural conditions,large land resources and low quality,and the ecological environment is relatively fragile.Therefore,it is very necessary to study the impact of changes in the use of land resources in Lanzhou New District on the ecological environment.Based on the analysis of the current situation of land use in Lanzhou New District and the changes in land use since the construction of the new district,this study found: The total land area of Lanzhou New District in 2016 was 174,408.05 hm2,of which 91.45% were agricultural land,7.85% were construction land,and 0.7% were natural reserves.(1)From 2012 to 2016,the area of agricultural land in the New District increased by 27.45%,of which the cultivated area decreased by 6.72%,the garden area decreased by 0.49%,the pasture area increased by 44.79%,the forest area increased by 0.36%,and the pasture area increased significantly.The change in cultivated land area is mainly due to the conversion of dryland,dry sand land,and abandoned land to non-irrigated dry land,which has no significant impact on the ecology.The reduction in garden area has mainly changed into other agricultural lands;the large-scale increase in forest area has affected the ecology.It has not yet fully emerged.The newly added forest lands are mainly based on unforested afforestation land,nurseries,forestry production,etc.,which relieves the erosion of wind and sand and plays a role in preventing soil erosion.(2)The area of construction land increased by 1267.45 hm2,of which the urban land area increased by 3249.72 hm2,the traffic construction water use land increased by 560.6 hm2,and the natural reserve area decreased by 28.18%.The increase of urban construction land area caused PM10 and PM2.5 to exceed the standards,which affected the air quality;the rainfall decreased from 300 mm to 219.9 mm before 2010,and the rainfall decreased significantly,And surface water,groundwater total nitrogen,and total phosphorus were significantly exceeded.It shows that the increase of urban and rural living land affects the hydrological and meteorological environment and the quality of water bodies;the change of urban and rural construction land area has no significant impact on the soil quality of the new area,and the soil quality meets the requirements of environmental quality standards.The increase in the area of transport construction land is mainly due to the increa se in the area of exposed bare land,which has caused an increase in dust-flood weather in the New District;the increase in the area of land for water conservancy facilities is mainly due to the use of the water supply channels of “drawing into the Qin Dynasty”,due to the extensive use of water resources in traditional agricultural production.Soil secondary salinization in some irrigation areas is intensified.It was mainly transformed into the area of forest land and construction land,and had a negative effect on the ecological environment in the short term.In the long-term,it had a positive effect on ecological environment protection.(3)The results of land ecological sensitivity in Lanzhou New District show that the ratio of low sensitive area,insensitive area,moderately sensitive area and highly sensitive area to the new area is 69.64%,30.10%,0.23% and 0.03%,respectively.The analysis results of the bearing capacity of land resources in the New District indicate that the northern region is suitable for the development of industrial clusters of wind and sand and new areas,the central area is mainly for water conservation and ecological agriculture,the central area is suitable for building urban life function areas,and the south is suitable for constructing urban tourist wetland ecological landscapes.There is an urgent need for the development and management of barren hills in the west.