Desenvolvimento de Urochloa brizantha adubada com fonolito e inoculada com bactérias diazotróficas solubilizadoras de potássio

Abstract

The objective of this study was to analyze the feasibility of using phonolite rock powder in Urochloa brizantha cv. Marandu and whether the inoculation with potassium solubilizing diazotrophic bacteria (K) contributes to a greater development and bromatological characteristics of this forage. The experiment was conducted in pots containing 15 dm3 of soil, during three cutting periods. A randomized block design in a factorial scheme and an additional treatment (4x3 + 1) were used, with four doses of phonolite (100%, 75%, 50% and 25%) and three inoculant variables (UNIFENAS 100-13, UNIFENAS 100-94 and a control without inoculation), further, was added the additional treatment with potassium chloride (KCl), with four replicates per treatment. At the time of each cut, the morphological and bromatological parameters of the forage were evaluated. The different doses of phonolite associated with inoculation with the bacterial strains showed no significant differences in morphological parameters, such as leaf width and length, tillers density and dry matter. However, phonolite promoted an improvement in the bromatological characteristics in the parameters of acid detergent fiber, hemicellulose, dry matter digestibility, total digestible nutrients, digestible and metabolizable energy, thus contributing to the improvement in nutritional value, indicating the potential of this rock as an alternative source to potassium chloride (KCl).