一定区域内的土地特征,是该地自然条件的全面综合反映。因此,在土地类型调查研究基础上,按照土地结构的相似性和差异性,自下而上地合并自然区划单位,更能准确地反映客观实际。

The climate of Guiyang belongs to monsoon type of humid subtropical zone. Geo-morphologically it is essentially a karst plateau. Landscape is varied. The chief factors of land differentiation are geomorphology, lithology, and soil-vegetation. Based upon these factors and taking land facet as mapping unit, 8 land types of the first order may be distinguished. They are subdivided into 22 land types of the second order and 77 land types of the third order.The land types, their proportions of area, and their patterns in a certain region are referred to as the structure of land types. According to similarity and difference of the structure, the land types are grouped into 22 land systems, or minor regions (land system local form), which can be studied as individuals. This is physico-geographical regionalization of the lowest order mapping in smaller areas with a larger scale. When mapping in larger areas with a smaller scale they can be grouped into land system abstract in taxonomic study. These minor regions are further grouped into 5 physico-geographical regions. In this way, units of higher level can be grouped step by step. This approach links up land classification and physico-geographical regionalization.In this paper, natural features, measures of improvement and utilization for each, land type are also studied. The land structure and the directions of agricultural development for each regions are described.The agricultural development of an aroa depends mainly on the water-heat condition, the land structure and the social-economic function of agriculture. After analysing the characteristics of these aspects of Guiyang, the author points out the following strategical policies should be adopted for agricultural development: (1) To expand the diversification of economy and concentrate the subtropical cash crops. (2) To stren-then the intensive agriculture and raise the productivity. (3) To take the reforestation and extension of land cover as the essential method to resume ecological balance, the long-term objective of which is to recover the zonal evergreen broad-leaf forest on mountains and hills and to establish varied natural-cultural ecological systems conforming to the local conditions.