THE CLASSIFICATION OF AGROECOSYSTEM TYPES WITH CLUSTER ANALYSIS IN BEIJING SUBURBS
用聚类分析划分京郊农业生态系统类型

In this paper. 57 specific attributes which arc suitable for the classification of the village level aprofCoSystems are selected according to the principles of agroeccSy-stem. These specific attributes are taken for classifying the agroecosystems of 77 villages (production brigades) in some counties of Beijing suburbs and 5 methods of non-overlapping intrinsic hierarchical agglomerative analysis are adopted4The results are as follow: except the single linking method, the other methods adopted can classifty the villages clearly into \ major types: the less intensive farming mountain areas,the middle intensive farming plain areas, the highly intensive farming environs and the specific type. The Ward's hierarchical classification method is better than the others in this classification. With less threshold values, some subtypes were found. The differences among the units in the plain areas are smaller and the structure of it's units are steady, but the units closed to urban in third type are influenced by the city, the differences are obvious and the structure of it's units is unsteady.