Suitability,Stability And Its Spatio-temporal Distribution Of Well-facilitated Farmland Construction

Farmland is foundation to ensure the national food security.Well-facilitated farmland is high-quality farmland,it is the material basis for ensuring national food security and accelerating modern agricultural development.The 13rd Five-Year Plan Outline clearly needs to ensure the completion of 800 million mu farmland,strive to build up to 1 billion mu of well-facilitated farmland by 2020,and play an active role in improving the stability and production of food and increasing the incomes of farmers.However,there are problems in the construction process that the capital investment are not matched with the natural endowment of land resources,the diversification of investment and the difficulty of giving full play to benefits.The root cause of yield lies in the lack of scientific guidance in site selection and planning and design of well-facilitated farmland construction projects.Therefore,the evaluation of spatial suitability and stability of well-facilitated farmland construction and the study of its spatio-temporal distribution are carried out systematically,which provides technical support for the design of site selection and planning scheme of well-facilitated farmland.It has become an important subject in the field of well-facilitated farmland research in China.In this paper,using the theory of niche-fitness,location theory,landscape ecology theory and sustainable development theory,taking Xinzheng city,Henan Province as the research area,soil field sampling data,the land foundation data such,Landsat TM,SPOT5 and other remote sensing image data are used as the main data sources.The spatial suitability and stability evaluation and space spatiotemporal distribution of well-facilitated farmland construction are systematically studied by using GIS spatial analysis technology.Based on the theory of niche-fitness,spatial suitability,stability evaluation and difficulty degree of obstacle factor transformation of farmland construction with coupling,a decision system of space-time distribution of farmland construction with well-facilitated was constructed,and time sequence of farmland construction was determined.It realizes the unity of economic benefit,social benefit and ecological benefit,and provides theoretical and scientific support for the establishment of well-facilitated farmland.The main contents and conclusions are as follows:(1)Based on the theory of niche-fitness,the theoretical framework of well-facilitated farmland niche is constructed,and the connotation of well-facilitated farmland niche is defined.The construction of well-facilitate farmland is restricted by many resource factors,such as natural endowment condition,landscape ecological condition,infrastructure condition,spatial stability and so on.Each factor has an appropriate threshold for the construction of well-facilitated farmland,and in all the areas defined by these thresholds,any point constitutes a combination of environmental resources that meets the construction standards of well-facilitated farmland,all these state combination of points constitute multidimensional hypervolume niche of well-facilitated farmland.(2)The evaluation system of spatial suitability for farmland construction with well-facilitated farmland was constructed.According to the matching degree between the space of farmland real niche-fitness and the space of the most suitable niche,the suitability grade was classified,and the suitability degree of farmland construction in different regions was determined.The results show that although the topographic and geomorphological conditions in Xinzheng city are complex,the overall natural endowment of cultivated land is better and the suitability degree is higher.The suitability index is above 0.65 and the total farmland area is 50792.43hm~2,accounting for 93.76%of the total farmland area.According to the analysis of the suitability of each index,the slope and the concentrated degree are the key factors affecting the construction of well-facilitated farmland in Xinzheng city.(3)The evaluation system of spatial stability of well-facilitated farmland construction was constructed.The spatial stability of well-facilitated farmland in Xinzheng city was classified by using niche suitability model,and the spatial stability degree of farmland in various regions was clarified.The results show that the location of farmland in Xinzheng city,the degree of convenience for cultivation,the total area of planning constraint ecological control and niche suitability index less than 0.5 accounted for 12.99%,5.42%,17.46%and 0.52%respectively of the total farmland area.The convenient degree and ecological control of farmland have little influence on the spatial stability of farmland.The main factors restricting the spatial stability of well-facilitated farmland construction are planning constraints and location conditions of farmland.According to the suitability index,the spatial stability of farmland in Xinzheng was divided into four degrees that is stable,relatively stable,less stable and instability,they accounted for 53.52%,16.67%,7.67%and 22.05%of the total area of farmland of the city.To ensure the permanent stability of farmland,well-facilitated farmland construction projects should be arranged in stable and relatively stable areas as much as possible.(4)The coupling function model of spatial suitability and stability evaluation of well-facilitated farmland construction is constructed,which ensures that the farmland with high standard has not only good natural endowment conditions,but also a stable spatial distribution,besides it improved the field operation of farmland project construction.The results show that the total farmland area of Xinzheng city,which basically has well-facilitated farmland construction conditions is 21059.54hm~2,accounting for 38.88%,and the area of farmland which could reach to well-facilitated farmland construction condition if we control it is 15561.28hm~2,accounting for28.73%,the total farmland area of 4326.66hm~2,which need to be comprehensively renovated in order to meet the construction conditions of well-facilitated farmland,the area of land which is not suitable for the construction of well-facilitated is 13220.45hm~2,accounting for 24.41%.According to the coupling spatial distribution,the farmland with well-facilitated farmland construction conditions is mainly distributed in the southwest of Xinzheng city.The area is mainly distributed in plain area,with good irrigation and drainage conditions,high degree of continuous farmland and stable spatial pattern.It is the first choice area of well-facilitated farmland construction.The farmland which is not suitable for the construction of well-facilitated farmland is mainly distributed in the central and eastern regions,which is the main expansion area of the construction land during the 13rd Five-Year Plan period of Xinzheng city.The spatial stability is poor and it is not suitable for the construction of well-facilitated farmland.(5)Based on the theory of niche-fitness,the niche model and index deviation degree model were combined to construct the obstacle indicators diagnosis based on niche-fitness,and the restriction degree and difference of each obstacle factor to farmland quality were analyzed.The emphasis and direction of farmland construction in different regions are clarified.The results show that the natural endowment condition of farmland in southwest area of Xinzheng city is better and the obstacle degree of evaluation factor is not high.It is the first choice of well-facilitated farmland construction.The main obstacle to the construction of well-facilitated farmland in the eastern region is that the irrigation and drainage facilities in the larger areas can no longer meet the needs of the current agricultural development.In some areas,the content of soil organic matter is low and the soil is polluted to some extent.(6)Based on the analysis of the degree of difficulty and ease of coupling evaluation of zoning and obstacle factor transformation,the decision of space-time layout of well-facilitated farmland construction was made according to the order of first easy and later difficult.Then,in view of the obstacle factors which can be reformed under the current economic and technological condition,the paper puts forward the model of well-facilitated farmland construction,and the countermeasures and measures to ensure the construction of this model.The results show that most of the farmland in the priority construction area conforms to the construction standard of well-facilitated farmland,and can be directly classified into the high well-facilitated farmland area.In the medium-term construction area,the main obstacle factor is gradeⅠ,and the difficulty of farmland transformation is relatively small.And the input is small but output is high and it is the well-facilitated farmland key construction area.The long-term construction area should be distributed around the town and along the traffic line,which is difficult to build and need to be built for a long time.The main obstacle factor of unsuitable construction area is spatial stability,which belongs to the non-revamping factor,and is not suitable for the construction of well-facilitated farmland.