Abstract: Vegetation change and its causes were discussed through analyzing the relationship between herbage yield and the Normalized Difference Vegetation Index (NDVI) in August and precipitation in early May to middle July during 2005-2008. The results showed that NDVI changed significantly in most regions, the region with increasing NDVI extended, and vegetation grew better than last year. Regions with decreasing NDVI mainly distributed in middle and east of the Grassland, which indicated that herbage degradation was serious. Grassland vegetation changes and herbage yield fluctuation were significantly to precipitation in late June.

Key words: font-family: 宋体, mso-bidi-font-family: 宋体, mso-font-kerning: 1.0pt, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, mso-bidi-language: AR-SA">Remote sensing, Grassland, Vegetation, Change