Abstract: By using the 1988—2002 data of annual mean precipitation and evapotranspiration in the Heishui River basin of Minjiang River upper reach, and with the help of GIS, a comparison was made on the annual mean runoff coefficient of the watersheds with different landscape structure in the Heishui River basin. The results showed that the magnitude of the annual mean runoff coefficient was in the sequence of forest-shrub watershed<forest-grass-shrub watershed<forest watershed<forest-grass watershed, which was related to the land cover type, mean altitude and windward slope direction. For forest watershed and shrub watershed, the annual mean runoff coefficient was affected by mean annual precipitation, mean annual evapotranspiration and mean slope grade. For forest-grass and forest-grass-shrub watersheds, the annual mean coefficient was affected by mean annual precipitation , mean annual evapotranspiration, and the ratio of forest/grass area.

Key words: Simulated acid rain, Soluble sugar, Nitrogen content, Photosynthetic rate, Nitrate reductase