| The self-regulatory capacity of the mountain ecological environment is poor,and the contradiction between people and land is outstanding.Especially in the context of rapid social and economic development,external interferences such as population increase and environmental pollution increase have made the farmland ecosystem of Sanmenxia City more sensitive.Sanmenxia is located in the junction of Henan,Shaanxi and Shanxi,belonging to the the Yellow River triangle area and the node city of the economic belt of the Silk Road.Its ecological environment is of great significance to Henan province and even the whole country.The ecological background of Sanmenxia is good,but with the rapid development of economy and the accelerated process of urbanization,the unordered expansion of urban space is constantly invaded the cultivated land and ecological space.The problems of land degradation and ecological environment deterioration caused by the overuse of cultivated land resources seriously destroy the stability of the cultivated land.Therefore,to evaluate the ecological sensitivity of the cultivated land ecosystem in Sanmenxia,and to provide an important reference for the formulation of different patterns of cultivated land use and development by understanding its sensitivity and its change.This paper uses the theory of system science,ecological economics,sustainable development and spatial geography,which is related to the sensitivity of cultivated land ecosystem,taking Sanmenxia as the research object,taking remote sensing image data and socioeconomic data as the basic data.Under the support of GIS technology,a combination of qualitative and quantitative methods was used to study the changes in cultivated land use and cultivated land ecosystem susceptibility from 2000 to 2015 in Sanmenxia City,specifically including three aspects:(1)Quantitative analysis of the quantity change,utilization rate,utilization degree and spatial and temporal differentiation characteristics of cultivated land in Sanmenxia city were carried out,and corresponding qualitative descriptions were made.(2)Using the bivariate correlation analysis and principal component analysis method in SPSS software,the main social and economic factors affecting the change of cultivated land use are found out.(3)The sensitivity evaluation index system of cultivated land ecosystem is constructed,multi factor weighted sum model is used,and different sensitivity grades are divided,and then the change of sensitivity is analyzed and evaluated.The main conclusions are as follows:(1)Forest land,cultivated land and grassland are the main types of land use in Sanmenxia City.In 2015,among all land use types in Sanmenxia City,woodland accounted for the highest proportion of total land area,accounting for 42% of the city's land;followed by arable land,accounting for 34% of the city's land;grassland ranked third,accounting for the city's land 19%,other land types such as water,urban and rural areas,industrial and mining,and residential land account for a small proportion,and the proportion of unused land accounts for the least.(2)The change of cultivated land use in the city of Sanmenxia is overall slower,but there are great differences in the use of cultivated land in the counties/cities under its jurisdiction.This article analyzes the change of cultivated land use from four aspects: quantity change,utilization speed,utilization degree,and spatial and temporal differentiation characteristics:(1)From 2000 to 2015,the area of farmland in Sanmenxia City increased first and then gradually decreased.However,the area of cultivated land in 2015 was still higher than the initial cultivated area in 2000.The area of irrigated land remained unchanged,and the changing trend of dryland area and the total area of cultivated land.The trend of change remains the same.For the six counties(districts)under the jurisdiction of Sanmenxia City,the changes in the dry land area in the Hubin District,Lingbao City and Shan County are consistent with the change in the total cultivated land area in Sanmenxia City,in Dianchi County,Lushi County,and Yima City.The areas of dry land in the three regions all show a trend of decreasing annual area of dry land area over time.(2)In terms of changes in the use of cultivated land,the dynamics of cultivated land use in Sanmenxia City is relatively small,but the dynamics of cultivated land use in the six counties(districts)under its jurisdiction are greater.Among them,the farmland use change in Yima City is the largest,and Lingbao City is the second largest.Mianchi County ranks third,and the degree of arable land use in Hubin District,Lushi County,and Shanxian County is relatively small,but it is higher than that of Sanmenxia City.(3)In the degree of utilization of cultivated land,Sanmenxia City's land reclamation rate has changed little,but the land reclamation rate of the six counties(districts)under its jurisdiction has changed greatly.The land reclamation rate has declined in Yima City,Mianchi County,Shanxian County,and Lushi County,and the areas with increased land reclamation rates are Lingbao City and Hubin District.(4)In the spatial and temporal characteristics of cultivated land use,the cultivated land in Sanmenxia City and its jurisdiction over 6 counties and cities is distributed on each elevation zone,and as the elevation increases,the distribution area of cultivated land is less and less,showing a clear vertical differentiation rule,and the distribution area on the different slope zones is reduced with the increase of the slope.(5)The increase of cultivated land area is caused by the transformation of the water,grassland and woodland to the cultivated land,in which the water area is the main source of the increase of cultivated land in Sanmenxia,and the direction of the lost arable land is the woodland,the construction land and the water area,and the main reason for the loss of cultivated land is the construction and ecological land reclamation.(3)The most important driving factor of cultivated land use change is economic development,followed by agricultural science and technology progress and industrial structure adjustment.With the rapid economic development,the process of urbanization and industrialization has accelerated,which has led to an increase in the area of cultivated land used for urban construction;the level of agricultural science and technology has a direct impact on the use of arable land and the amount of output,thus alleviating the pressure of population growth on food and land demand;with the continuous development of the secondary industry in the adjustment of industrial structure,the total industrial production value has been continuously increased,and the demand for cultivated land has increased year by year;the impact of urbanization level on the change of cultivated land use is mainly achieved by the conversion of cultivated land to construction land;the development of traffic promotes the conversion of farmland around traffic corridors into construction land.In addition,an important socio-economic factor that influences changes in arable land use is policy factors.(4)The ecological environment of arable land in Sanmenxia City has been improved year by year,and the overall level of ecological susceptibility has increased first and then decreased.From 2000 to 2005,the sensitivity Index of cultivated land ecosystem in Sanmenxia City showed an increasing trend,and the sensitivity level increased from mild sensitivity to high sensitivity.From 2005 to 2010,the sensitivity index of cultivated land ecosystem in Sanmenxia City showed a downward trend,and the sensitivity level consisted of The high sensitivity becomes moderately sensitive,and the sensitivity index of cultivated land ecosystem in Sanmenxia City continues to decline from 2010 to 2015,and the sensitivity level changes from moderate sensitivity to insensitivity.The sensitivity level of cultivated land ecosystems in Sanmenxia City was reduced from highly sensitive to insensitive within the study period,and the ecological environment was significantly improved,the main reason is that the government and farmers pay more and more attention to cultivated land resources,and the policy of cultivated land protection is increasing. |
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