Allelopathy Among Prairie Grasses and its Possible Ecological Significance

Abstract

The phytotoxic effect of four kinds of litter and three kinds of fresh material extracts of blue grama and western wheatgrass on seed germination of blue grama, western wheatgrass and buffalo grass was tested. The four kinds of litter were collected from the Ecosystem Stress Area at the native shortgrass prairie site. These included litter from control, fertilized, irrigated, and fertilized plus irrigated plots. The three kinds of fresh materials were harvested from blue grama and western wheatgrass growing under growth chamber conditions at three distinct phenological stages. Results indicated that the fresh material extracts were more phytotoxic than the litter extracts and among the former the fresh material harvested at the earlier phenological stage was more phytotoxic than those collected at the advanced phenological stage. Chemical composition of litter and fresh material indicated that the fresh materials contained comparatively more phenolic substances than that of litter materials.