Low nitrogen fixation of common bean (phaseolus vulgarisL.)

Nitrogen fixation activity in legumes varies among species and common bean (Phaseolus vulgaris L.) is known to exhibit a lower ability to fix nitrogen than other legumes such as soybean (LaRue and Patterson 1981; Nishimune et al. 1983). Therefore, the dependence of common bean on nitrogen fertilizer is considerably higher than that of soybean (Matsushiro 1971). At least, three factors may contribute to the low nitrogen fixation observed in common bean: (1) delay of nodule appearance on root system, (2) insufficient nodule mass on root system, and (3) ineffectiveness of nodules formed on root system. In this paper, the nodulation and nitrogen fixation of common bean and soybean were investigated using the root-box-culture technique.