Cultivo de grão-de-bico inoculado com bactérias fixadoras de nitrogênio

Abstract

Biological nitrogen fixation (BNF) plays a crucial role in sustainable agriculture by providing a low-cost nitrogen supply for crops and reducing environmental impact. In the context of chickpea cultivation, the nitrogen accumulation by diazotrophic bacteria highlights the potential of BNF to meet the crop's nitrogen needs. The use of plant growth-promoting rhizobacteria has shown promise in enhancing BNF and improving the productivity of legumes, indicating the possibility of reducing nitrogen fertilization through BNF. However, the efficiency of BNF in tropical regions, such as the Cerrado, requires further research to optimize it and increase agricultural production in these areas. In this context, this study aimed to evaluate the effects of inoculation and co-inoculation with nitrogen-fixing bacteria, along with the application of molybdenum and organic fertilization, to explore the potential of BNF and its impact on the growth and productivity of chickpeas in sandy Cerrado soil. The experiment, conducted in randomized blocks with four replications and a 2x2x4 factorial scheme, considered the presence or absence of organic fertilization, molybdenum, and four inoculation methods (Bradyrhizobium japonicum, Azospirillum brasilense, Bradyrhizobium japonicum + Azospirillum brasilense, and no inoculation). After 89 days of planting, the following parameters were evaluated: shoot and root length, stem diameter, number of pods, dry mass of the shoot (MSPA) and roots (MSR), total dry mass (MST), and accumulation of N, P, and K in the chickpea's shoot and root. The use of cattle manure had a positive impact on all evaluated characteristics, promoting sustainability in the production system by aiding in nutrient accumulation and the growth of chickpea plants. Organic fertilization with cattle manure increased soil fertility, favoring nutrient absorption and plant growth. Seed inoculation with Bradyrhizobium japonicum in the presence of fertilization without molybdenum, and inoculation with Azospirillum brasilense with organic fertilization and molybdenum resulted in the longest chickpea root length. On the other hand, the use of a commercial inoculant of Bradyrhizobium japonicum for this study showed inefficacy in chickpea nodulation.