| With the development of economy and society,the increase of population and the deterioration of soil environment,the contradiction of cultivated land resources in our country was becoming more and more serious,which posed a great threat to national food security and social stability.Henan was one of the 13 major grain producing provinces in China.It was of great significance to study the cultivated land security in order to ensure the national grain security.Based on the analytic hierarchy process(AHP)and TOPSIS model,this paper established the evaluation index system of cultivated land security in Henan province by selecting quantity,quality and ecological index,and carries on time and space analized on the quantity,quality,ecology and comprehensive safety of cultivated land resources in Henan Province from 2007 to 2016.The main conclusions ware as follows:(1)The total cultivated land of Henan Province in 2016 was 8110.01hm2,including dryland,irrigated land and paddy field,mainly dryland and irrigated land.The proportion of the former two to cultivated land was 34.53% and 56.11%,respectively,and the proportion of paddy fields was only 9.3%,mainly distributed in Nanyang Basin,Huang-Huai Hai Plain and Loess Hilly area.With the increase of agricultural mechanization and effective irrigation area,the total grain yield and per unit yield in Henan Province increased from 5245 in 2007 to 5245 in 2007,with the increase of agricultural mechanization and effective irrigation area,the total area of cultivated land and the per capita cultivated land area of Henan Province decreased continuously after 2009 because of the rapid increase of construction land and population.The lack of organic matter and water resources limits the improvement of cultivated land quality and grain yield in Henan Province.In 2016,the use of chemical fertilizer,pesticides and agricultural film in Henan Province reached 881.2 kg/hm2,15.65kg/hm2,which seriously threatened the ecological security of cultivated land.(2)The safety index of cultivated land quantity in Henan Province in 2007-2016 was 0.530,which belonged to the basic security level.The safety index of cultivated land quantity in Henan Province increased from 0.514 in 2007 to 0.539 in 2009.The safety of cultivated land quantity increased from the critical safety level to the basic safety level from 2009 to 2015.The safety index of cultivated land quantity in Henan Province fluctuated slightly in 0.539,which was in the basic safety level.Safety Index of cultivated Land quantity reduced to 0.495 in Henan Province in 2016 The security situation was reduced from basic safety to critical security level;From the spatial dynamic point of view,in 2007,the safe areas of cultivated land quantity and the basic security zone in Henan Province were mainly distributed in the east of Henan Province.After 2012,the pattern of safe cultivated land quantity in Henan Province was obvious,the situation was obvious,and the safety of cultivated land quantity in Henan Province deteriorated in 2016.The amount of cultivated land was not safe to spread to the eastern part of Henan Province.The main obstacle factors affecting the safety of cultivated land in Henan Province were per capita cultivated land area,per capita grain yield and cultivation rate.(3)The average value of quality and safety index of cultivated land in Henan Province from 2007 to 2016 was 0.532,which belonged to the critical safety level.It had experienced three stages: raising,steady and fluctuating from 2007 to 2010.The quality and safety index of cultivated land in Henan Province increased from 0.483 in 2007 to 0.537 in 2010.The cultivated land ecology increased from unsafe level to security sensitive level.2010-2014.The index of cultivated land quality and safety in Henan Province was about 0.539,which was in the year 2014-2016.Quality and Safety Index of cultivated Land in Henan Province The security level was low,raising from 0.538 to 0.551 in 2016.From the spatial dynamic point of view,the pattern of cultivated land quality in Henan Province was significant in the period of study,and the area of safe area and basic safety zone was expanding continuously.The main obstacle factors affecting the quality of cultivated land in Henan ware the content of organic matter,the yield of grain per unit and the financial support of agriculture.(4)The average value of ecological security index of cultivated land in Henan Province in 2007-2016 was 0.581 which belongs to the critical safety level,and it had experienced a short period of ascent and continuous decline from 2007 to 2009.The cultivated land ecological security index increased from 0.605 in 2007 to 0.655 in 2009,and the grade was upgraded from security sensitivity to critical safety.From 0.655 in 2009 to 0.548 in 2016,the security level changed from critical to sensitive and unsafe.From space The ecological security and safety zone of cultivated land in Henan Province ware mainly located in the west and south of Henan Province,and the ecological safety zone and the basic safety zone of cultivated land in Henan Province have gradually decreased since 2009.The main obstacle factors affecting the ecological security of cultivated land in Henan Province ware chemical fertilizer,pesticide and environmental protection expenditure,which accounted for the proportion of financial expenditure.(5)The average value of comprehensive safety index of cultivated land in Henan Province from 2007 to 2016 was 0.549,which belonged to unsafe level.Overall,the comprehensive safety index of cultivated land in Henan Province declined.The index of comprehensive security of cultivated land in Henan Province increased from 0.536 in 2007 to 0.574 in 2009,and the comprehensive security level of resources was upgraded from no safe zone to sensitive area in 2009-2014.The comprehensive safety index of cultivated land resources in Henan Province decreased from 0.574 in 2009 to 0.542 in 2014.From 2014 to 2016,the comprehensive security index of cultivated land in Henan Province fluctuated frequently,from 0.542 in 2014 to 0.553 in 2015 and down to 0.531 in 2016.During the study period,the spatial distribution of comprehensive security of cultivated land in Henan Province was significant,and the change was small.The optimum area of comprehensive security of cultivated land was mainly located in southeast Henan Province,the safe sensitive area was mainly located in the east of Henan Province,and the security zone was located in the western part of Henan Province.The influence of cultivated land quantity,quality and ecological security on the comprehensive security of cultivated land in Henan Province was 0.34%,0.35%,0.31,respectively.The situation of cultivated land security was severe.(6)Based on the study of temporal and spatial differentiation of cultivated land safety and the diagnostic results of obstacle factor,the following suggestions ware put forward for cultivated land safety in Henan province.The quantity of cultivated land should be strictly controlled,the proportion of high-yield farmland should be increased,the population quantity should be controlled,and the quality of cultivated land should be improved to improve the content of organic matter in soil,save water,and strengthen the construction of irrigation and water conservancy facilities.The ecological aspect of cultivated land was to make rational use of agricultural materials such as chemical fertilizer,pesticide and agricultural film,to strengthen rural pollution treatment facilities,and to raise the awareness of ecological protection of cultivated land. |
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