Landuse Evolution And Driving Mechanism In Typical Karst Trough Area

Karst Valley is one of the typical landforms in Karst landforms,but there is little research about it.With its special topographic characteristics,only through long-term and multi-scale exploration of the evolution of land use,we can understand the human-environmental relationship under this environment,to master the law of development of human-environmental relationship in Karst landforms.Yin Jiang county was taken as an example,to explore the spatial and temporal changes of land use in Karst Valley.According to the research ideas from large-scale county to mesoscale trough to small-scale settlement,from the perspectives of land use structure,land use evolution quantity,speed and land use under different elevations,slopes and other topographical conditions,various research methods are used,combined with time background,economic background and changes in infrastructure construction,To explore the temporal and spatial evolution of land use in karst troughs and valleys,the following conclusions are drawn:1.The main types of land use in the Karst Valley area are dominated by grasslands,arable land and forest irrigation land.The law of temporal evolution is characterized by the fact that 1990 is the time node.Before 1990,the number of forest irrigation land decreased,and the number of cultivated land and grassland increased,and vice versa.The types of land use in each district are similar,but the speed of change and the number of changes are different.The construction land hotspot is located at the Valley area,and its economic development is higher than that of other regions.2.Cultivated land and forest irrigation fields have obvious fluctuations at different times.Its amount of arable land increased before 1990,and its growth curve decreased over time;After 1990,the area of arable land was shrinking,and its shrinking curve was increasing over time.Variations in fluctuations vary from region to region.3.The land use change law of Langxi Valley is bounded by 1999.In terms of time,the time limit of land use change in the west slope and the bottom of the valley is 1999,which is faster than the time boundary point of the east slope.On the elevation,the higher the elevation of the west slope and the bottom of the valley,the less the type of land use,and the smaller the area of each land use type.DongPo is the opposite.The higher the altitude,the more balanced the area of land use.4.The evolution law of land use in settlements takes 2004 as the time node.The extended settlements show the location closer to the center of the settlement,and the richer the land use type.But atrophic settlements appear to be closer to the center of the settlement,and the less land use type.The equilibrium invariant settlements show that the change of land use type is not affecte by the distance settlement,but it is related to the economic degree of settlement.5.The land use time and space changes in the county are influenced by the economic development level,population,agricultural policies,etc.Thus,the land use in the Karst Valley area shows a changing space-time dynamics.From a small scale,the development of land use in the valley is also affected by terrain factors,transportation factors,and settlement development factors.