Layout optimization of rural settlements in mountainous areas based on farming radius analysis

Abstract: Rural settlements consolidation is an important way for China to optimize the layout of rural settlements, and the farming radius is one of the important factors that need to be considered in the consolidation planning of rural settlements. In this paper, taking Xichang City, Sichuan Province as a case, the layout optimization method of rural settlements in mountainous areas based on farming radius analysis was discussed. First of all, the characteristics of rural settlements and the suitable farming radii in valley-plain area, gentle-slope area, steep-slope area were analyzed respectively. Then, in order to identify the locations of central villages, the farming radii of 3 regions (slope 0-6°, ≥6°-25°, ≥25°) under 7 scenarios (current situation, only retaining rural settlements of >0.5, >1, >2, >3, >4, >5 hm2, respectively) were analyzed. The Euclidean distance analysis tool in ArcGIS 10.2 was used to analyze the farming straight-line distance, and it can obtain the specific values of the average straight-line distance and the maximum straight-line distance in the study area, as well as the service range of different rural settlements. The network analysis tool in ArcGIS 10.2 was used to analyze the farming path-distance, and it can analyze the path-distances of different farmland patches to their nearest rural settlements and the service range of different rural settlements. The results show that the patch number of rural settlements in Xichang is 24367 and the total area of rural settlements is about 7764 hm2, accounting for about 2.9% of the total area of Xichang City, the average patch area is 3186 m2, and per capita area of rural settlements is 172 m2. The number of micro- and small-scale rural settlements in Xichang City accounts for 94.8% of the total number, so it is necessary to realize the intensive use of rural residential land by rural settlements consolidation. The average farming radius of Xichang is 147 m, and the farming radii of 3 regions increase linearly with the small rural settlements gathering to larger rural settlements. The ratio of micro- and small-scale rural settlement is steep-slope area > gentle-slope area > valley-plain area, so the relocation of micro- and small-scale rural settlements has the greatest impact on the farming distance in steep-slope area, followed by the gentle-slope area, and has the lowest impact on the valley-plain area. The suitable farming radii are 3000-4000, 750-950 and 550-750 m in the valley-plain area, gentle-slope area and steep-slope area respectively. The rural settlements in the valley-plain area should be gathered to the rural settlements of more than 3 hm2, which could not only form bigger villages but also meet the farming radius requirements. Some rural settlements in the gentle-slope area can be gathered to the rural settlements of more than 1 hm2 and have convenient traffic, so as to form a rural residential area with a certain scale. The consolidation of rural settlements located in the steep-slope area has little significance, and should be promoted in cooperation with the projects of "Returning farmland to forest and grassland", "Poverty alleviation and relocation in other places", "Protection and restoration of mountainous areas", and these rural settlements should be gradually migrated to the gentle-slope area and valley-plain area.