USE OF A COMPARATIVE APPROACH TO IDENTIFY ALLELOPATHIC POTENTIAL AND RELATIONSHIP BETWEEN ALLELOPATHY BIOASSAYS AND COMPETITION EXPERIMENTSFOR 10 GRASSLAND AND PLANT-SPECIES

Various allelopathy bioassays were used to evaluate the allelopathic p otential of 10 grassland forage species against a common test (phytome ter) species, Carduus nutans L. Aqueous extracts did not influence C. nurans germination, although radicle elongation was often severely inh ibited. C. nutans was strongly affected by shoot, but not root, leacha tes. Decomposing ground tissue had mixed effects, and often stimulated shoot production of C. nutans. Calculation of R(2) (coefficient of de termination) values between these results, and the results of previous experiments investigating the effects of the same 10 species on C. nu tans emergence and development in field plots and glasshouse competiti on experiments frequently revealed strong, statistically significant r elationships. Our results therefore provide correlative evidence for t he importance of allelopathy in field conditions.