关键词: 灰渣场, 土壤酶, 植被状况, 土壤化学性质

Abstract: By using GIS technology, this paper studied the patch dynamics of cropland and grassland in Zhangye oasis, Gansu Province in 1985-2006. In the study period, the predominant patch types of cropland were unchanged and expanded patches, while those of grassland were unchanged and shrunk patches. The common features of the patch dynamics of cropland and grassland were the largest mean area of unchanged patches (214.64 hm² for cropland and 149.5 hm² for grassland) and their smaller patch number and shape index, suggesting the patches having a higher aggregation degree in landscape scale and a concentrative and successive distribution, and the smallest shape index of newly generated patches (23.88 for cropland and 15.58 for grassland), suggesting their aggregative distribution. The differences of the patch dynamics of cropland and grassland were that cropland landscape was expanded mainly in the form of small patches on the basis of original patch, while grassland landscape was dominated by the shrinkage of original patch. In terms of the origins and fates of the patches, there existed a strong transformation among the cropland, grassland, and Gobi (matrix) patches in Zhangye oasis in recent two decades, and the main forces driving this transformation were population growth, water resources restriction, economic development, and climatic change.

Key words: Coal cinder yard, Soil enzyme, Vegetation state, Soil chemical properties