Eficiência de ureia e inibidor de urease no cultivo de milho
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Data
2025-08-05
Autores
Souza, Denilson Almeida de
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Universidade Federal do Espírito Santo
Resumo
Maize (Zea mays L.) is a crop of high economic and nutritional importance, widely used for silage production in Brazil. Among nutrients, nitrogen plays a decisive role in growth, development, and yield, with urea being the main source applied in agriculture. However, volatilization losses reduce its efficiency, making the adoption of urease inhibitors a relevant alternative. In this context, this study aimed to evaluate the agronomic and economic efficiency of conventional urea compared with urea treated with the urease inhibitor NBPT, under different nitrogen rates, in maize cultivated for silage production. The experiment was conducted in Alegre, Espírito Santo State, Brazil, during the 2023/2024 growing season, in a randomized block design. Physiological variables (chlorophyll a, chlorophyll b, flavonoids, and nitrogen balance index) and morphological traits (plant height and stem diameter) were assessed under a split-split plot arrangement (2 × 4 × 3), with two N sources, four rates (0, 50, 100, and 150 kg ha⁻¹), and three phenological stages (V5, V9, and tasseling). Productive variables (leaf, stem, and ear dry matter, total dry matter, silage yield, and leaf N content) were evaluated under a split-plot scheme (2 × 4). The results revealed significant interactions among nitrogen source, rate, and phenological stage for physiological and morphological traits, highlighting the temporal dependence of maize response to N management. NBPT-treated urea enhanced nutrient use efficiency, resulting in higher chlorophyll contents, greater nitrogen balance index, increased plant height and stem diameter, and, most importantly, greater dry matter accumulation and silage yield. Yield responses followed a quadratic pattern, with intermediate doses providing the highest results, whereas higher doses did not translate into additional gains. The economic analysis showed that NBPT-treated urea provided higher net returns per hectare, outperforming conventional urea despite its higher initial cost. It is concluded that NBPT use is an effective and sustainable strategy to optimize nitrogen fertilization, increase productivity, and ensure greater economic viability in maize silage production.
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Nutrição mineral , NBPT , Fertilização nitrogenada