USE OF MICROALGAE REMOVED FROM LAKE AÇU FOR THE DEVELOPMENT OF ORGANOMINERAL FERTILIZER
maize; sustainability; eutrophication.
Brazil has a high dependence on imported mineral fertilizers, which increases agricultural production costs and contributes to environmental impacts such as soil acidification and the eutrophication of water bodies. In this context, organomineral fertilizers, which combine mineral nutrients and organic matter, present a promising alternative. This study aimed to evaluate the use of microalgae from Lago Açu, an eutrophic water body located at the Federal Rural University of Rio de Janeiro (UFRRJ), in the formulation of organomineral fertilizers (OMF). The microalgae were cultivated using the Algal Turf Scrubber (ATS) system, collected weekly, dried, ground, and chemically and biologically characterized. The biomass was used in different proportions and combined with mineral sources of phosphorus and potassium to formulate the OMF, which were applied to pots containing two types of soil (Argisol and Planosol) cultivated with maize (Zea mays L.). The experiment was conducted for 45 days in a randomized block design, in a 2x7 factorial scheme, with four replicates. The dry mass of the aerial part of the plants and the effects of the treatments on the chemical properties of the soil were evaluated. Data were analyzed by ANOVA and Tukey's test at 5% significance. The results showed that the application of microalgae-based OMF improved plant nutrition and soil fertility, demonstrating the potential of this biomass as a sustainable agricultural input.