城市化是推动都市农业形成及结构转变的主要驱动力,探究快速城市化过程中都市农业结构变动特征对协调城市与都市农业功能及其可持续发展具有重要意义。本文通过农业结构变化率、农业结构系数、农业产业结构转换方向系数等指标,研究了城市化过程中西安都市圈都市农业结构变动特征及其空间分异。结果表明:(1)西安都市圈城市化的快速发展,导致都市农业粮油生产比重持续下降,水果、蔬菜生产以及农业休闲服务比重上升,农业结构逐渐向特色化、现代化发展。(2)1999-2006年,是西安都市圈低城市化水平向较高城市化水平发展阶段,是推动都市农业结构快速调整与转变的重要阶段;2006年之后由于城市对农产品及休闲服务的需求结构格局已基本确定,类型的多样性需求相对减缓,主要以数量需求增加为主,因此农业结构变化则相对较小。(3)随着城市化水平的提高,农业结构系数降低,都市农业结构层次逐渐趋于高级化,都市圈核心区比边缘区农业结构层次更高。(4)西安都市圈各区县谷物种植业转换方向系数均小于1,谷物种植业向蔬菜、果业及休闲农业的转换较为突出,都市圈农业正向现代都市农业转变。

Urbanization is main driving force to the urban agriculture development and its structural transformation within metropolitan. To explore the conversion characteristics of the urban agricultural structure has a great significance in optimizing the relation of urban function and urban agriculture and their sustainable development in the process of rapid urbanization. Based on the indicators of agro-structure, agro-structure coefficient and agro-structure conversion direction coefficient, we analyzed the spatial-temporal conversion of agricultural structure in Xi'an metropolitan zone during 1999-2013. These results were as follows: ①Rapid urbanization resulted in huge changes of proportion in urban agriculture with the gradual decrease of grain crops production and the great increase of vegetables and fruits production and agro-recreation services in Xi'an metropolitan zone. A significant conversion occurred from traditional agriculture to urban modern agriculture, which showed that there were more intensive, fresh and ecological production, larger proportional agro-recreation services and high-tech facility's inputs. ②From 1999 to 2006, the rapid improvement of urbanization from low to higher level greatly promoted the urban agricultural structure adjustment and shift to modern agriculture in Xi'an metropolitan zone; Thereafter as the demand structure for agricultural products and services from citizen was constantly stable, the change ratio of agricultural structure gently dropped; ③With the enhancement of urbanization level and the reduction of urban agro-structure coefficient, the hierarchy level of urban agricultural structure gradually evolved into higher stages, and there was higher hierarchy level in urban area than in urban fringe and suburban area in space; ④The indicators of agro-structure conversion direction coefficient on grain crop in each district and county of Xi'an metropolitan zone all were less than 1, which showed that the transformation from planting to vegetables, fruit and the cultural leisure industry was more outstandingly. Agriculture was changing towards modern agriculture in metropolitan.