Atributos Microbiológicos do Solo Cultivado com Milho Inoculado com Solubilizadores de Fosfato em Duas Fontes de Fósforo

Abstract

Phosphate-solubilizing microorganisms play an important role in releasing inorganic forms of phosphorus, making a higher P content available in the solution, resulting in improved plant growth and higher yields. The utilization of phosphate-solubilizing bacteria can enhance the effects of phosphate fertilization, influencing soil quality. This study aimed to evaluate the microbiological attributes of soil inoculated with phosphate-solubilizing microorganisms using different phosphorus sources. The experiment was conducted in the experimental area of the Federal University of Mato Grosso do Sul, Campus Chapadão do Sul (CPCS/UFMS), under conventional system. The experimental design was a randomized complete block design, in a 2x4 factorial scheme, with four replications. The first factor consisted of two phosphate sources (ST - triple superphosphate and PR - rock powder), and the second factor comprised four different types of inoculants (T1 - no inoculation, T2 - inoculation with Azospirillum brasilense, T3 - inoculation with Bacillus bacteria, and T4 - co-inoculation of Azospirillum brasilense + bacteria). Soil sampling was conducted during the maize flowering stage, at a depth of 0-15 cm, with samples taken from the row and inter-row areas at various points within the plot, resulting in a composite sample of 48 samples for the experiment. The samples were analyzed for soil microbial biomass carbon (CBM), soil microbial respiration (RBS), metabolic quotient (qCO2), mycorrhizal percentage (MIC), and spore density (DES). The utilization of phosphate fertilization with triple superphosphate combined with Azospirillum brasilense inoculation resulted in better performance in soil microbiological attributes. These attributes serve as indicators of biological activity and soil health, as they reflect the presence and functioning of beneficial microorganisms.

Keywords: Macronutrient, Azospirillum brasilense, plant-microorganism interactions.