河湟地区乡村聚落位序累积规模模型的实证研究

科学确定乡村聚落体系是落实乡村振兴战略和促进农业农村现代化的关键之一,研究乡村聚落规模分布规律有助于乡村聚落体系优化。基于理论假设推导出了位序累计规模模型的准确表达及其规律,在此基础上,比较研究了位序累计规模模型和乡村位序—规模法则在河湟地区的适用性和准确性,厘清了河湟地区乡村聚落规模分布的特征和演变规律。研究显示：① 位序累积规模模型是一个单调递增的凹函数（P ≥ 1）,函数表达式随着聚落规模分布的帕累托系数变化而变化。当1 ≤ P<1.20225时,S_i=aln(N_i)+b,拟合系数a与首位聚落规模呈正相关;当P ≥ 1.20225时,$S_i=be^{aln(N_i)}$,聚落规模变异系数和首位聚落规模与拟合系数a呈负相关关系,而与拟合系数b则呈正相关关系。② 位序累积规模模型在河湟地区乡村聚落规模分布研究中具有良好的适用性和准确性,而乡村位序—规模法则不适用。③ 河湟地区乡村聚落规模分布为接近于帕累托系数为2的均衡分布且总体趋于集聚。未来河湟地区应有序推进乡村聚落向自然和社会经济条件较为优越区域适度集聚,合理制定区域乡村聚落布点规划和实用性村庄规划,走人与自然和谐共生、城乡融合发展的具有河湟地区特色的乡村振兴道路。

An empirical study on rank cumulative size model of rural settlements in the Hehuang area

Scientific determination of rural settlement system is one of the keys to implement the strategy of rural revitalization and promote the modernization of agriculture and rural areas. Meanwhile, understanding the distribution law of rural settlement size is helpful for the optimization of rural settlements. In order to provide a reliable theoretical basis for the study of rural settlement size distribution and the optimization of rural settlement system, this article took the Hehuang area as an example, and explored a more accurate expression and law of Rank Cumulative Size Model based on the original Rank Cumulative Size Model. Then we examined the applicability and accuracy of the model in rural settlement size distribution compared with the Rural Rank-Size Rule. We also studied the characteristics and evolution law of rural settlement size distribution in the study area. The results show that: (1) Rank Cumulative Size Model is a monotonously increasing concave function (P ≥ 1), and its expression varies with the change of the Pareto coefficient of rural settlements. When 1 ≤ P < 1.20225, S_i = aln(N_i) + b, there is a positive correlation between the fitting coefficient a and the size of first settlements. When P ≥ 1.20225, $S_i=be^{aln(N_i)}$ the coefficient of variation of settlement size and the size of the first settlements are negatively correlated with the fitting coefficient a, and positively correlated with the fitting coefficient b. (2) Rank Cumulative Size Model is more suitable for the study of rural settlement size distribution in Hehuang as it has better applicability and accuracy; while the Rural Rank-size Rule is not applicable. (3) The rural settlement size in Hehuang nearly shows the equilibrium distribution pattern of Pareto coefficient 2 and tends to be more concentrated. In the future, the rural settlements should be concentrated in areas with superior natural and socio-economic conditions, and the layout of regional rural settlements and villages should be planned reasonably. Based on this, we can develop a rural revitalization path with the harmonious coexistence between human and nature, as well as between urban and rural development.