Host plant specificity in Rhizobium- Bean symbiosis and the interference of several nutrients

Abstract

Four greenhouse experiments were carried out to study host plant specificity in beans (Phaseolus vulgaris L.) and the interference of several nutrients. In these experiments, four commercial bean varieties and several more or less efficient Rhizobium strains were used. The results of the experiments showed that the efficiency of the symbiosis was dependent on both, strains and varieties. Molybdenum was essential for optimal nitrogen fixation. However excess, molybdenum was more detrimental to nitrogen fixation and nodulation than to plant growth. Potash and magnesium seemed to reduce nodulation and nitrogen fixation whereas calcium had a stimulating effect. These elements interferred equally in both varieties. Nitrogenous fertilizer however had inhibiting effects on nodulation which varied with the varieties.