FONTES ALTERNATIVAS DE SUPLEMENTAÇÃO POTÁSSICA PARA O MILHO: DINÂMICA NO SOLO, TEOR NUTRICIONAL E ASPECTOS PRODUTIVOS DA CULTURA

Abstract

With the significant increase in production and productivity in recent years, corn cultivation has been undergoing technological changes related to improvements in soil quality. Regarding nutritional requirements, it is observed that potassium absorption increases linearly with the increase in productivity. Thus, the goal of this study was to evaluate the potassium dynamics in the soil supplied by potassium chloride, concentrated vinasse, and polyhalite as well as the vegetative growth, grain production, nutritional potassium content in the corn plant, and the agronomic efficiency of the different potassium managements with potassium chloride and concentrated vinasse. Two experiments were carried out. Experiment 1: The experiment was set in the Hydraulics and Irrigation laboratory together with the Soil Chemistry laboratory, belonging to the Instituto Federal Goiano – Campus Rio Verde, Goiás, Brazil. A distroferric Red Latosol, with clay texture, and a typical Ortic Quartzarenic Neosol were used. Rigid PVC columns were used, with the following potassium sources: potassium chloride, vinasse, and Poly4. To determine the potassium and sodium content, samples with 30 mL of effluent were collected. The DISP-1.1 software was used to calculate the solute transport parameters in the soil: retardation factor, dispersive-diffusive coefficient, and elution curve. The potassium ion was retained with higher intensity in the distroferric Red Latosol, showing higher interaction with the clayey soil and had greater leaching in the Quartzarenic Neosol, while sodium demonstrated higher retardation factor values in the Quartzarenic Neosol. For both ions, the vinasse source demonstrated less leaching when compared to the potassium chloride and Poly4 sources; Experiment 2: The test was conducted in an experimental field in the city of Rio Verde – GO. The experimental design used was randomized blocks, analyzed in a simple experiment scheme, with 4 replications, totaling 20 experimental plots. Treatment 1 = KCl - 100% of the potassium dose applied via potassium chloride at the V4 phenological stage in the corn crop; Treatment 2 = Vinasse - 100% of the dose of potassium applied via concentrated vinasse at the V4 phenological stage in the corn crop; Treatment 3 = Vinasse + KCl - 50% of the dose of potassium applied via Potassium Chloride and 50% via concentrated vinasse at the V4 phenological stage in the corn crop; Treatment 4 - Vinasse 2x 100% of the dose of potassium applied via concentrated vinasse at the phenological stage of V4 and V8 in the corn crop; Treatment 5 = Vinasse 2x + KCl 2x - 50% of the dose of potassium applied via Potassium Chloride and 50% via concentrated vinasse at the phenological stage of V4 and V8 in the corn crop. Mixed potassium supplementation via potassium chloride and concentrated vinasse does not benefit the corn grain productivity, and the isolated use of potassium chloride or concentrated vinasse is recommended. The use of 100% potassium via concentrated vinasse provides the greatest nutrient agronomic efficiency.