Amenização do estresse de fósforo na Braquiaria inoculado com Bacillus no solo de cerrado

Abstract

Grasslands in the closed soil are subject to different degrees of degradation. In this context, the use of plant growth-promoting microorganisms (PGPMs), such as inoculants, becomes an indispensable strategy to reduce the degradation of pastures, improve feed biomass and increase the productivity and sustainability of livestock in Brazil. Several studies have highlighted the benefits of PGPM, especially bacteria of the genus Bacillus. In this context, the hypothesis of this research was that the application of Bacillus aryabhattai could mitigate phosphorus deficiency (P) stress in Brachiaria brizantha. The aim of this study was to evaluate the mitigation of P stress in the productivity of the forage Brachiaria brizantha cv. Mulate II at different concentrations of P. The experiment was controlled in a delineation of randomized blocks on a 2x5 factor scheme with four repetitions. The treatments consisted of presence or absence of B. aryabhattai (associative bacterium) and five levels of P (0 = severe deficiency, 150 = moderate deficiencies, 300 = control, 450 = excess and 600 mg kg soil = over-excess). During the study, estimates were made of the green and dry mass of the leaves, the height of the plants, rebroth height, profiling, the results of this study provoked that the presence of the bacterium B. aryabhattai helped mitigate the stress of P, providing a greater number of leafs, increased profiling and rebrotting of the Brachiaria brizantha cv. by Mulato II. These findings highlighted the importance of plant growth-promoting microorganisms in improving grassland productivity under conditions of nutritional stress.