The Temporal And Spatial Changes And Driving Force Of Cultivated Land Quantity And Quality In Miluo

As the most important production factor in nature,cultivated land is the key factor in promoting the sustainable and healthy development of agriculture,maintaining the stability of the ecosystem and ensuring national food security.Strengthening the monitoring of the quantity and quality of cultivated land is conducive to the scientific,rational and unified management.It is impotent to protect and improve the quality of cultivated land.Therefore,this paper takes the analysis of the spatial and temporal changes of the quantity and quality of cultivated land in the research area of Miluo City,Hunan Province.The driving factors of the cultivated land are analyzed by using Principal Component Analysis(PCA),and then identify problems and provide suggestions based on actual conditions.The results achieved are as follows:(1)Miluo City's cultivated land area in 2011 was 49,752.67 hectares,in 2017 was50,737.40 hectares,which increased 984.73 hectares from 2011 to 2017.Among them,1061.46 hectares were increased in 2011-2014 with 7.1‰ change dynamic degree,and only0.66 hectares were increased in 2014-2015 with 0.04 change dynamic degree.Until2015-2017,the cultivated land area decreased year by year by 77.39 hectares.Attitudes increased from 0.47‰ in 2016 to 1.1‰ in 2017.(2)The quality of cultivated land in Miluo City is good,the area of 1nd to 3rd grade was accounting for about 84%.The comprehensive evaluation of cultivated land quality in2011 and 2017 is 2.92 and 2.89,and the overall quality of cultivated land is on the rise.The1 st grade increased 439.62 hectares and the proportion increased by 0.84%.The 2nd grade increased 1423.72 hectares and the proportion increased by1.89%.The 3rd grade decreased895.55 hectares and the proportion decreased by 2.44%.The 4th grade decreased 225.32 hectares and the proportion decreased by 0.6%.The grade increased.The 6th,7th,8th grade increased a little with 85.95 hectares,125.69 hectares and 30.62 hectares.(3)The main driving force for the change of cultivated land quantity and quality in Miluo City was has carried out land development,land reclamation,land consolidation,high-standard farmland construction,rural irrigation and water conservancy construction and so on.From 2011 to 2017,a total of 1274.91 hectares were increased,including 1212.87 hectares of land development with the average quality grade was 3.94,and 62.04 hectares ofland improvement with the average quality grade was 4.47.From 2011 to 2017,290.18 hectares of cultivated land were reduced.Among them,260.01 hectares of construction occupation were reduced,the average quality grade was 3.31.6.99 hectares of agricultural restructuring was reduced,and the average quality grade was 3.27.18.8 hectares of ecological conversion was reduced,and the average quality grade was 3.78.4.38 hectares of arable land was reduced net,and the average quality grade was 3.42.Principal component analysis shows that the main driving factors to improve the quality of cultivated land are irrigation guarantee rate,drainage condition and soil organic matter content.The latent factors are barrier layer depth from the surface,soil pH and topsoil texture.(4)The pH of soil of cultivated land in Miluo City in 2017 was 5.36.The pH less than5.5 was 36030.06 hectares,accounting for 71.01% of the total cultivated land.The area of acidic soil was larger.The average of soil organic matter content was 23.05g/kg,of which only 13.53% was greater than 30 g/kg,66.25% was 20-30 g/kg,and 20.23% was less than 20g/kg.It was generally of medium to low level.The soil layer is shallow,and the cultivated area with the thickness of 18-20 cm is only 2525.71 hectares,which accounts for 6.04% of the total cultivated area.The irrigation and drainage facilities need to be improved.A small part of cultivated land lacks drainage facilities.The cultivated land without irrigation facilities has 4973.11 hectares,accounting for 9.80% of the total cultivated land area.The phenomenon of occupy high-grade and supplement low-grade was aggravated.From 2011 to2017,the average cultivated land quality grade of newly added cultivated land was 4.07,and that of reduced cultivated land was 3.34.It is necessary to rational application of chemical fertilizers,increased application of organic fertilizers,deepening the thickness of the topsoil,strengthening the infrastructure of farmland and implement the policy of balance between the occupation and the supplement cultivated land,so as to maintain the results of cultivated land improvement.