Comprehensive Evaluation Of Cultivated Land Quality And Analysis Of Obstacle Factors In Mountainous Area In Southwestern Hubei

Agriculture is the foundation of the national economy and cultivated land is the most basic means of production of agriculture.Therefore,the quantity and quality of cultivated land resources have a major impact on the sustainable development of the national economy and society.Compared with the tangible reduction of cultivated land area,the deterioration of cultivated land quality is invisible,and its impact is no less than the former.The deterioration of cultivated land quality is a threat to China's food security and social stability.The primary condition for maintaining sustainable development of agriculture is to ensure the quantity and quality of cultivated land.Therefore,the evaluation of cultivated land quality has become more and more important.Carrying out the survey and evaluation of cultivated land quality levels,and grading the quality of cultivated land can fully understand the quality,area and distribution of existing cultivated land.It has important practical significance to improve the overall quality and utilization level of cultivated land and promote the sustainable development of agriculture.The southwestern mountainous area of Hubei Province is located in the southwestern part of Hubei Province,including Enshi Tujia and Miao Autonomous Prefecture,Shennongjia Forest Region,Yichang City and Shiyan City.It is located in the hinterland of the Three Gorges.The terrains are steep and the landforms are broken.The area is the most widely distributed,most concentrated and most serious soil erosion in Hubei Province.The investigation and evaluation of cultivated land quality in this area can make us understand the main problems in the current use of cultivated land.It has research significance and practical significance.In this study,Hefeng County of Enshi Tujia and Miao Autonomous Prefecture was used as the typical research area.The research year was 2017.Fourteen evaluation indicators were selected from five aspects:site conditions,physical and chemical properties,nutrient status,soil management and ecological environment.Constructed the evaluation index system and used the Delphi method and the membership function and the analytic hierarchy processed to determine the weight and membership degree.Then calculated the quality comprehensive index according to the analytic hierarchy process.Finally evaluated the quality level of the cultivated land.According to the degree of influence on the quality of cultivated land and the feasibility and difficulty of improving the current fertility,seven obstacle factors such as pH,organic matter and organic phosphorus were selected,and the obstacle function model was introduced to quantitatively analyze the seven obstacle factors.The obstacle degree was tentatively divided into four levels:barrier-free,level I,level II,and level III(%).Finally,adopted improvement measures based on the characteristics of obstacle factors to improve the quality of cultivated land.The research results are as follows:(1)The total cultivated land area of Hefeng County was 24080.05 hm2,dominated by the levels from the fourth to ninth of cultivated land quality.The average quality level was 6.70.We found that the cultivated land quality was dominated by level 7,accounting for 10778.07 hm2(44.76%);followed by level 6 accounting for 4278.96 hm2(28.70%).In 2017,the overall quality of cultivated land in Hefeng County was the medium-lower level.(2)The values of physical and chemical properties of arable soil in each township were quite different.The general condition of soil bulk density,pH,available potassium and slow-acting potassium in Hefeng County were medium or bad but organic matter,total nitrogen and available phosphorus were good.(3)The cultivated land of different quality levels in Hefeng County showed significant spatial staggered distribution characteristics.The overall spatial distribution pattern of cultivated land quality presented an obvious trend of low in northwest and southeast and high in north and southwest of Hefeng County.The cultivated land with relatively high quality level was concentrated in the north,south and southwest of Hefeng County,including towns and towns such as Taiping Town,Rongmei Town and Wuyang Township.Among them,there were no level-4 cultivated land distribution in Zouma Town and Tielu Township.The cultivated land with relatively low quality level was mainly distributed in the northwest and southeast of Hefeng County,including Zhongying Town,Xiaping Township and Tielu Township.(4)The main obstacle factors affecting the improvement of cultivated land quality in Hefeng County were mainly level I,indicating that the measures to be taken for quality improvement in this area were less difficult and the possibility of improvement was higher.Specifically,for obstacle factors,the obstacle degree of cultivated land quality improvement was dominated by level I from medium quality level to high.For details,there was no obstacle degree of organic matter,cleanliness,and farmland forest network degree in cultivated land quality improvement.The obstacle degree of pH and drainage capacity were mainly level I and effective phosphorus was mainly level II.The obstacle degree of irrigation capacity was mainly level III.As for obstacle factors,the obstacle degree of cultivated land quality improvement was dominated by level I from low quality level to medium.But the difference was that the range of obstacle degree of the obstacle factors had extended,showing that the difficulty of quality improvement had increased.Specifically,there was no obstacle degree of organic matter,cleanliness,and farmland forest network degree in cultivated land quality improvement.The obstacle degree of pH and drainage capacity were mainly level I and effective phosphorus was mainly level ?.The obstacle degree of irrigation capacity was mainly level ?.