Field evaluation of Rhizobium inoculant formulations for alfalfa

Abstract

In an on going study, granular Rhizobium inoculants for alfalfa are being compared to pre-inoculated seed and on-site peat inoculated seed for their effects on alfalfa stand establishment, nodulation, forage yield and biological nitrogen fixation. In addition, depth of inoculant placement is being investigated. Field sites were established in 1999 at three locations in the alfalfa production area of Saskatchewan. Treatment effects varied by site, however in general on-site inoculation resulted in inferior stand establishment and forage yield in the establishment year. Plots where granular inoculants were banded below the alfalfa seed row generally had the best stand establishment and yields in the establishment year. Treatment differences disappeared by the first cut of the first production year. Thus, although granular inoculants may lead to superior establishment they do not appear to have a long term benefit. They study will continue for a third year.