| The complex and diverse geomorphic types in Chongqing provide a variety of basic backgrounds and different development directions for the regulation of high-standard farmland in the region.Exploring the construction mode of high-standard farmland under different landforms is helpful to improve the cultivated land environment more pertinently and to seek more scientific and efficient ways of high-standard farmland construction.This paper intends to construct the evaluation index system of high-standard farmland construction potential and the evaluation standard of the advantages and disadvantages factors around the regional industrial development goals,then,based on the characteristics of geomorphic pattern in Chongqing,the potential size,advantages and disadvantages of high-standard farmland construction of different geomorphic types are analyzed integratively,at the last,the key contents and modes of high-standard farmland construction in different geomorphic areas are determined through three cases of different geomorphic background project areas.To do these,the following work and research have been carried out:Referring to the description of landform types in Chongqing high-standard farmland construction technical requirements(trial),mainly based on morphology and elevation of elevation difference,the farmland geomorphic types in Chongqing are divided into Valley flat dam/Shallow hilly belt dam(elevation less than 500 m,relative height difference less than 20m),Hilly wide valley(elevation less than 500 m,relative height difference less than 50m),Low-mid mountain(elevation greater than 500m)and other types.Starting from the content and basic definition of high-standard farmland construction,four criteria layers including topographic conditions,irrigation and drainage conditions,road conditions and ecological conditions were established.A total of 11 indicators were selected to construct a high-standard farmland construction potential evaluation index system.Taking the potential indexes as the influence factor of industry development,the standard of judging the quality factor of industry development was established.Under the landform background of Valley flat dam and Shallow hillock belt dam,agricultural industry development type is relatively single,aiming at realizing mechanized and efficient grain and oil production.These areas have a large potential for high-standard farmland construction and many advantages,but disadvantages including degree of fragmentation,irrigation and drainage conditions,and road surface texture.In high-standard farmland construction project,this landform area should give full play to the advantages of relatively flat terrain,put orderliness farmland as the target of tilling field construction,to reduce the degree of fragmentation and regular field shape;The ideal scale of the construction is 5~8mu,while the actual suitable scale is 3~10mu.The corresponding wide side is between 30~100m,and the long side is between 50~150m.After the planning,the number of field blocks per unit area decreases significantly.Relying on the planning results of orderliness farmland,the irrigation and drainage facilities are scientifically and rationally arranged to improve the irrigation guarantee rate in the project area and the current situation of drainage difficulties.On the basis of the orderliness farmland planning,the existing road pattern and the pavement material in the field can be improved.The scale of orderliness farmland construction depends on specific crops.Under the background of Hilly broad valley landform,agricultural industry development is more abundant than Valley flat dam and Shallow hilly belt dam landform.Rice,grain and oil production are the main production,some special agricultural products or ecological cultivation are developed,too.There are many advantages,and disadvantages of industrial development in these areas,such as degree of fragmentation,pavement texture,etc.the field slope,land fragmentation,and terrace rate need to be improved,especially in the dry land.Centering on the cultivation of characteristic agricultural products or other dryland crops,the engineering construction in this geomorphic area mainly focus on the regulation of gentle slopes.The regulation of gentle slope is classified according to the slope and scale of the present block.The gentle slope which grade under 15°and has larger scale can be improved as diffuse slope,and after regulation field slope should be less than 10°.In other cases,the dry land is generally regulated as horizontal terraces or slope terraces,and among them,we can regulate the land with a small slope as horizontal terraces,while the large slope as slope terraces.If the slope of the table is less than 15°,the slope of the background surface of the remediation should be less than 6°,and if the slope is greater than 15°,the slope of the background surface of the remediation should be no more than 10°.With reference to the River valley flat dam area/Shallow hillock with dam area,the paddy field area should be treated as strip field.Field roads and drainage and irrigation systems are mostly arranged on the basis of planned plots,at the same time,ecological protection works should be given attention to,to reduce soil erosion.Roads should be properly hardened according to industrial needs.Under the background of Low mountain landform,the industrial development is diversified,and the grain and oil industry presents a trend of gradual shrinkage.The construction potential of high-standard farmland in this area is poor,and there is fewer advantage;disadvantages in the development of agricultural industry include the improvable and the difficult to improve.It is difficult to improve the degree of crushing and the slope of field through engineering transformation,therefore,the emphasis of the construction of high-standard farmland project in the geomorphic area is to carry out the integrated layout of infrastructure centering on different industrial development needs.For example,the vegetable industry faces the market,so the arrangement of irrigation,drainage,roads and other supporting facilities must meet the market demand;Grain and oil industry zone should focus on changing the weak quality of grain and oil production;The density of road,irrigation and drainage facilities should be suitable for the Seedling base.Therefore,in the process of production road layout,the distance between grain and oil production roads is less than 100 m,the spacing of vegetable production roads is less than 150 m,seedling base production road spacing is less than 200m;The requirements for field roads and production roads in different industries are same.The maximum spacing between field roads is less than 500 m,while the maximum distance between production roads is less than 350 m.The layout of ditches in vegetable and grain and oil bases should be rain-free for 40 days in the drought and hot season,and rain-free for 70 days in other seasons,and daily rainfall of 150 mm is not flooded.the standard of seedling base can be appropriately lowered. |
