Growth and yield of white bean (Phaseolus vulgaris L.) in response to nitrogen, phosphorus and potassium fertilizer and to inoculation with Rhizobium

Two white bean (Phaseolus vulgaris L.) cultivars grown for 2 yr on test plots of a long-term fertilizer trial showed a significant response to nitrate in the first year and in the 2 yr combined but not in the second year on its own. Yield in the second year was about half of that in the first year, possibly because of water stress. Bean yield was lowest in the zero nitrate, about equally high for 112 and 224 kg N ha −1 , but somewhat lower at 336 kg N ha −1 . Annual application of potassium and phosphorus (compared to no application for 12 yr) did not affect bean yield, but increased plant dry weight after 24 d in 1984 and the 2 yr combined, after 38 d in 1984 and after 52 d in 1983 and also increased the number of days to maturity. Nitrate effects on the dry weights of samples taken during the growing season were similar to those for bean yield. Acetylene reduction rates (first year) and nodule weights were highest in zero N and declined to very low values at 336 kg N ha −1 . Acetylene reduction rate per plant reached a maximum value early in the season and declined to low values before bean filling was complete. Rhizobium inoculation had no discernible effects on dry weights or yield, but a small significant effect on days to maturity. We conclude that these white bean cultivars are unable to fix sufficient nitrogen to produce maximum yield.Key words: Field bean, Phaseolus vulgaris, nitrogen, Rhizobium