In Furrow Co-inoculation of Rhizobia and Azospirilla Influences the Growth and Productivity of the Common Bean.

Besides being a significant part of the Brazilian national economy, the common bean is a legume whose grains are part of the daily diet of the population of developing nations globally. Combining N-fixing bacteria and plant phytohormone producers through the use of inoculants is an alternative to improve plant growth and increase grain yield in the common bean production system. This study aimed to evaluate the effect of co-inoculation doses with Rhizobium tropici and Azospirillum brasilense, applied in the planting groove, on nodulation, growth and productivity parameters of the common bean. Five field experiments were conducted in a randomized block design with four replications. Restrictions were formulated, namely: absolute control, without fertilization and without co-inoculation (AC); nitrogen fertilization (NfT); single inoculation of R. tropici (Rt); R. tropici + one dose of A. brasiliense (Rt + Ab1f); R. tropici + two doses of A. brasiliense (Rt + Ab2f); R. tropici + three doses of A. brasiliense (Rt + Ab3f); R. tropici + four doses of A. brasiliense (Rt + Ab4f) and R. tropici + three doses of A. brasiliense (RP). The number of nodules (NN), nodule dry mass (NDM), aerial dry mass (ADM), root dry mass (RDM), pod number (NP), number of grains (NG), mass of 100 grain (100G) and grain yield (GY) were taken. The Rt + Ab4f co-inoculation provided a significant increase in NN, NDM, ADM and RDM values than the Rt and AC treatments. In addition, it also presented the highest GY stability, with an average production of 3499 kg ha− 1 from the five sites, which represents an increase of 15.4%, 14.8%, 11.0%, and 1.0% as compared to Rt, AC, RP, and NfT treatments, respectively. The results indicate the feasibility of the use of co-inoculation with R. tropici and A. brasilense in commercial production farms and for small producers in several countries of the world with similar edaphoclimatic conditions, reducing the use of nitrogen fertilizers, production costs and the prevention of negative environmental impacts. [ABSTRACT FROM AUTHOR]