An approach of interference between Dichanthium ischaemum (L.) Roberty and Chrysopogon gryllus (L.) Trin. by replacement series experiment

The warm season perennial grass species Dichanthium ischaemum (L.) Roberty and Chrysopogon gryllus (L.) Trin. dominate in the low and middle elevation grasslands in northern Greece. Intraspecific competition and the tolerance to the influence of grazing determine their relative abundance. The experiment was designed to study the interference between D. ischaemum and C. gryllus. It was conducted following the “replacement – series” (de Wit model) experimental design that is based on a constant total density (286 individuals/m2) and different relative proportion 100:0, 75:25, 50:50, 25:75, 0:100. Measurements of the plant height were taken during the growing season. Plant biomass (over- and underground) was measured at the end of the growing season. The index of the Relative Total Yield (RYT) was estimated. Plant height was higher at the proportion 75:25 and 25:75 for D. ischaemum and C. gryllus respectively. The estimated RYT in the above densities was >1 indicating lack of competition and a relationship of symbiotic interference between the species.