Resposta morfológica e aspectos agronômicos do feijoeiro à reinoculação via cobertura

Abstract

Bean culture has been shown to be increasingly responsive to nitrogen fertilization, in order to increase grain yield. In addition to nitrogen fertilization, there are other processes that constitute sources capable of supplying large amounts of nitrogen to plants, such as biological nitrogen fixation (BNF). Considering the relevance of BNF in common beans, there is a need for further research aimed at investigating the positive associations of BNF processes in the crop. The objective of the study was to evaluate the morphological response, nodulation and agronomic aspects of two bean cultivars submitted to supplementary inoculation via cover (reinoculation). The experiment was conducted in the 2019/2020 water harvest, in the experimental area belonging to the State University of Goiás - UEG, Ipameri University Unit, Ipameri-GO. The design used was in randomized blocks, in a 2 x 4 factorial scheme, with four replications. The treatments consisted of two genetic materials of common bean (BRS Pitanga and BRS Valente), submitted to four methods for nitrogen supply (MNS): T1 - conventional, with application of N; T2 - inoculation via seed with Rhizobium tropici + supplementary reinoculation via cover; T3 - inoculation exclusively via seed; T4 - inoculation exclusively via cover. The cultivar BRS Pitanga, with inoculation via seed, associated with reinoculation via cover, presented a greater root dry mass than when submitted to the other treatments. The stem diameter and plant height also showed greater results with BRS Pitanga. The inoculation technique, regardless of the form of application, favors the agronomic and morphological aspects of the common bean. The bean cultivar BRS Valente provides better responses to inoculation. Inoculation via seed combined with supplementary reinoculation via cover provides an increase of 2,827 kg ha-1 in the grain yield of beans belonging to the BRS Valente cultivar, in relation to mineral nitrogen fertilization.