Avaliação da nodulação em diferentes estágios fenológicos do feijoeiro-comum

Abstract

The biological nitrogen fixation, a process that provides N to common beans, starts to contribute significantly to the nutrition of the plant between 15 and 20 days after its emergence. This process does not extend to the latest phases of the cycle, such as pod filling. According to the literature, the common bean has the ability to nodulate in advanced phases of its cycle, which, if confirmed, may result in increased grain yields. The aim of this work was to evaluate the occurrence of late nodulation on common beans and its contribution to the development of the plant under controlled conditions. First, an essay was carried out aiming at choosing the best substrate and irrigation methods to be adopted on the other experiments. Once the ideal substrate was defined, six experiments following a randomized block design were carried in a greenhouse. The nodulation was forced in different sections of the root system in four of these experiments. In the other two experiments, the effect of the re-inoculation of rhizobia in different plant development stages was evaluated. According to the obtained results, all irrigation methods had the same performance. The chosen substrate was the soil subsuperficial layer due to its low content of rhizobia. A significant difference in the number of nodules was observed in the experiments evaluating plant nodulation. The different strategies adopted to stimulate late nodulation were not sufficient to stimulate late nodulation, and the seed inoculation was effective enough to promote a well-developed plant