关键词: 羊草草地, 土壤, 全铁, 有效铁

Abstract: Based on the remote sensing and climatic data from 1982 to 2000 and byusing statistical analysis, the spatiotemporal variation pattern of vegetation’s net primary productivity (NPP) in China was studied. In the 20 years, only 8% of the land had a marked decrease of the NPP, 47% of the land was in adverse, while approximately 44% of it had little change. The annual vegetation’s NPP increased in most parts of the country but decreased in its eastern developed provinces or industrialized and urbanized regions, and, there existed obvious spatial differences in the variation rate of the annual vegetation’s NPP. The inter-annual relative variability of vegetation’s NPP was smaller in most parts of China, but greater in the desert grassland area of northwestern China.

Key words: Leymus chinensis grassland, Soil, Total iron, Available iron