Fertilization with Steel Slag in Pasture Production and Chemical Composition of Urochloa Brizantha in the Amazon

Objective: This study aimed to evaluate, in a pasture of Urochloa brizantha cv. Xaraés, the effect of different rates of blast furnace steel slag as a source of silicon, analyzing both biomass production and the chemical composition of the forage. Theoretical Framework: The research is based on the potential use of blast furnace steel slag as a silicate fertilizer for cultivated pastures of Urochloa brizantha cv. Xaraés, with the goal of increasing dry matter production and ensuring a chemical composition suitable for cattle production. Method: The experiment followed a randomized block design with four replications. Each experimental unit comprised 48 m² of pasture. Treatments consisted of applying 0, 200, 400, and 600 kg ha⁻¹ of steel slag, previously sieved to 2.0 mm. Thirty-three days after application, the first cut (simulated grazing) was carried out, followed by laboratory analyses and statistical evaluation. Results and Discussion: Due to the increase in dry matter yield, steel slag can be recommended for Urochloa brizantha pastures at a rate of 200 kg ha⁻¹. At this dose, the forage presented a chemical composition favorable to cattle production (lower acid detergent fiber content in leaves and stems, and higher crude protein content in stems). Research Implications: Industrial residues such as steel slags represent alternative nutrient sources for plants, and their use addresses the need to reduce waste accumulation in industrial centers. This agricultural reuse may also positively impact livestock production in continuous grazing systems in the Amazon, by promoting greater yield of high-quality forage. Originality/Value: Beyond offering an appropriate destination for an industrial by-product and its positive impact on forage production, the originality of this study lies in the assessment of the chemical quality of the increased biomass, which is essential for cattle nutrition. An increase in plant production alone would be insufficient if the material lacked favorable nutritional attributes for animal feed.