Inoculação e coinoculação de rizóbios e bacilos em feijão-caupi (Vigna unguiculata cv. BRS Tumucumaque)

Abstract

The effectiveness of inoculation and co-inoculation of rhizobia and bacilli in cowpea (Vigna unguiculata cv. BRS Tumucumaque) cultivation in Manaus, Amazonas, was evaluated in this study. The aim was to enhance biological nitrogen fixation and phosphorus solubilization, thereby improving fertilizer use efficiency. The study was conducted at Embrapa Western Amazon's experimental station using a randomized block design with nine treatments, including various combinations of Bradyrhizobium sp. (BR3267-SEMIA6462), native isolate rhizobia (AM200/2022 and AM212/2022), and the commercial inoculant BiomaPhos® (Bacillus megaterium and Bacillus subtilis). Evaluated parameters included shoot biomass, nitrogen accumulation, nodulation, yield, and root characteristics. The results indicated that co-inoculation with BiomaPhos® and AM200, as well as single inoculation with AM200 and AM212, significantly increased shoot biomass and nitrogen accumulation. Furthermore, nodulation was enhanced by the native isolates. Nevertheless, yield and grain quality exhibited no substantial disparities among the various treatments. Thirty days after emergence (DAE), co-inoculation with BiomaPhos® + AM200 and inoculation with AM200 and AM212 increased cowpea's dry shoot biomass. Co-inoculation with BiomaPhos® + AM200 and inoculation with AM200 increased nitrogen accumulation in cowpea shoots. Inoculation with AM200 and AM212 increased the dry nodule mass of cowpea. At 72 DAE, variables such as number of grains per pod, pod length, 100-seed weight, yield, and nitrogen and phosphorus content in grains were unaffected by inoculation and co-inoculation. These variables showed correlations among themselves.