Comparación entre coinoculación con Bradyrhizobium japonicum y Azospirillum brasilense e inoculación simple con Bradyrhizobium japonicum en la nodulación, crecimiento y acumulación de N en el cultivo de soja

the aim of this study was to compare coinoculation with bradyrhizobium japonicum and azospirillum brasilense with inoculation with bradyrhizobium japonicum on nodulation, growth, and n accumulation in the soybean crop in field conditions. two field tests were carried out for two years with different hydric conditions in areas not previously cultivated with soybean. the treatments were: control, coinoculation using bradyrhizobium japonicum + azospirillum brasilense and inoculation with bradyrhizobium japonicum. nodulation in both experiments was increased by dual inoculation, although significant differences were registered in the experiment with water deficiency. in both experiments, in coinoculation treatments yield mean values were higher than other treatment, although no significant differences were found. biomass and n accumulation by the crop was higher in the coinoculated treatment than in the simple inoculation in the wet year. in the dry-condition year, n derived from the biological fixation was 26% in the simple application and 30% in the coinoculation treatment and in the year without water deficit, these percentages were 41 and 47 % respectively. from these results we conclude that coinoculation has a positive effect of growth stimulation in soybean crops. however, we believe it is necessary to continue studying this subject further.