Microrganismos solubilizadores de fosfatos e fontes de fósforo na cultura da aveia-branca cultivada em um latossolo vermelho

Abstract

The chemical element phosphorus is considered an essential macronutrient for the development of plants and due to the low solubility in soils this nutrient is little available for use, for this, there is the possibility of using phosphate solubilizing microorganisms to promote an increase in the availability of phosphorus in the soil ground. White oat (Avena sativa) is an annual grass used as forage, for ground cover, production of grains, hay and silage and for human consumption. The objective of this work was to evaluate the solubilization potential of Azospirillum and Bacillus subtilis and Bacillus megaterium strains in bone meal and reactive rock phosphate in an Oxisol cultivated with white oat. The experiment was conducted in pots and installed in a protected environment located in the experimental area of the Federal University of Fronteira Sul, Erechim-RS campus. The experimental design was in randomized blocks - DBC and the arrangement of treatments in a 3x4 factorial scheme, with four replications. The phosphorus sources used were bone meal, reactive natural phosphate and the control treatment (without phosphorus source). The phosphate solubilizing microorganisms evaluated were Azospirillum, Bacillus subtilis and Bacillus megaterium strains, Azospirillum associated with Bacillus subtilis and Bacillus megaterium strains and the control (without inoculation). The parameters measured were plant height, stem diameter and phosphorus content in shoots and roots, in addition to physiological analyzes with a photosynthesis analyzer (IRGA - Infrared Gas Analyzer). Based on the results obtained, it can be concluded that the Azospirillum bacterium associated with reactive natural phosphate provided responses in stem diameter, plant height and phosphorus content in the aerial part of white oat, showing promise to increase the availability of phosphorus in the soil. Regarding the phosphorus content in the roots, there was no effect in any of the treatments.