杜能农业区位论的环状结构中,蔬菜种植位于第一圈层。中国现行农业生产体制下,这种环状结构会产生一些偏差。本文对河南省开封市蔬菜生产空间格局研究发现,开封市蔬菜种植存在由邻城市中心向外扩展的趋势,紧邻各县城中心分布较少,中远郊地区和交通便捷区分布广泛,形成整体分散、局部集中的格局。相关证据并不支持传统杜能环中的蔬菜圈层观点。这种分布特征受市场、交通、技术、地租等多方面因素的影响。该研究指出在中国国情和地理条件下杜能理论应用的局限,对农业生产区域化布局有一定的指导意义。

This paper studies the location of vegetable cultivation of some vegetable-specialized villages in Kaifeng through the field survey on agricultural production. These villages are all selected by rigorous selection process which have certain representation, certain size and certain level of specialization of vegetable production. And vegetables in this study refer in particular to vegetables which must be consumed freshly. We use ArcGIS10.0 software to analyze the spatial pattern of vegetable production of the selected villages. The research shows that the vegetable planting of each county in Kaifeng has a trend of extending outward from the areas near the city center. Data show that the location advantage of vegetable planting in the areas close to the county center has been weakened. The vegetables are mostly distributed in the areas where are over 10km away from the county center, especially concentrated in the areas where are between 10km and 15km away from and over 20km away from the town center. The vegetable plantation forms a spatial pattern of overall dispersion and local centralization, which is less distributed next to the downtown and widely distributed in the outer suburb areas and the traffic-convenient areas. And the operation modes of vegetables in the peri-urban areas are more diverse than the outer suburb areas. Overall, evidences from this study do not support the circle structure of vegetable cultivation in von Thunen's theory. In summary, this case study finds the deformation of von Thunen's circles under the national conditions and geography of China, which indicates the theory's limitations in practice.