Allelopathic effects of Cynodon dactylon L. plants in invaded natural grasslands

Abstract

We evaluated the allelopathic effect of the invasive species Cynodon dactylon from a natural grassland and overseeding grassland intersowing with legumes and fertilization with phosphorus, on two native grasses, Paspalum notatum and Paspalum dilatatum. Due to what was observed in fertilized grasslands, where the cover of C. dactylon increases, P. notatum decreases and P. dilatatum is not affected, it was expected that the allelochemicals from the intersowing and fertilized grasslands would have a negative effect on P. notatum.. Hie effect of aqueous extracts of C. dactylon on the germination, growth and development of the two grasses studied. Contrary7 to our expectations, we could not detect inhibitory effects of the treatments on germination and adult plants in autumn, but an increment of germination of both species irrigated with extracts from intersowing and fertilized grasslands, hi contrast, in spring, the responses were neutral. The results obtained do not indicate that aqueous extracts from fresh leaves have an allelopathic effect that explains the invasive success of C. dactylon and the decrease of P. notatum in fertilized grasslands, although other approaches should be considered for its study.