The influence of edaphic and competitive factors on productivity of marsh reed grass (Calamagrostis canadensis) in a cooperative pathosystem

Abstract

Calamagrostis canadensis (Michx.) Beauv., marsh reed grass, hinders the regeneration of conifer seedlings. The influence of nutrients, autoallelopathy, and intraspecific competition on the productivity of greenhouse-grown marsh reed grass inoculated with a combined Fusarium avenaceum (Fr.:Fr.) Sacc. – Pseudomonas sp. pathosystem was studied. The productivity of uninoculated plants increased following fertilization, but these increases were not observed in inoculated plants. Leaf damage in inoculated plants was enhanced by P and K fertilization, but shoot height was not affected. Autoallelopathic straw extract interacted with intraspecific competition to nearly double pathogenic inhibition of shoot growth at high levels of competition. The straw extract also interacted with N fertilizer to reduce shoot productivity. Shoot growth was inhibited at higher levels of intraspecific competition. Responses to nutrients, autoallelopathy, and competition may be useful in developing improved biological control strategies.Key words: Fusarium avenaceum, rhizobacteria, biocontrol, bioherbicide, fertility, soil ecology.