Abstract: Herbaceous species diversity and herbaceous community quantitative features in the riparian zone of East Liaohe River were studied with the sample line approach. To find the major environmental factors affecting the distribution pattern of riparian herbaceous communities, cluster analysis and ordination analysis were conducted by using group average clustering analysis and detrended correspondence analysis (DCA). Results showed that there were altogether 118 herbaceous species, belonging to 36 families and 70 genera. The herbaceous species diversity increased firstly and then decreased from upstream to downstream, while the richness index changed irregularly due to hydrological characteristics, riparian substrate types, soil moisture and human disturbance. The herbaceous communities were classified into 11 types using clustering analysis, and dominated by hygrophytes. Correlations between DCA ordination axes and environmental factors showed that the elevation and stream order were the major environmental factors affecting the distribution pattern of herbaceous communities in the riparian zone of East Liaohe River.

Key words: film mulching, hilly area of central Sichuan basin, root distribution, yield, spring maize, ridge-cultivation