Abstract:

Vegetation is one of the important indices to reflect the status of regional eco-environment， and the groundwater has significant impact on vegetation growth. Located in arid northwestern area, Yinchuan plain is the important industrial and agricultural base in Yellow River basin, and its condition of natural ecoenvironment is typical in northwest China. Combined with MODIS-NDVI and groundwater monitoring data, this paper studied the relation between groundwater and vegetation in Yinchuan plain from large scale. The relation curve between depth of groundwater and NDVI change rate was fitted based on least square method. The impact of groundwater on vegetation growth was analyzed quantitatively and the suitable depth of groundwater for the vegetation growth was discussed in this study. The result indicated that the vegetation growth is best as the depth of groundwater is 3 m, the suitable range of depth of groundwater for the vegetation growth is between 1 and 5 m. The impact of groundwater depth on vegetation is gradually weak if the depth of groundwater is larger than 5 m and the impact is zero if the groundwater depth is larger than 8 m.

Key words: MODIS-NDVI, depth of groundwater, NDVI change rate, least square method, Yinchuan plain