UREA RATES AND Azospirillum brasilense APPLICATION STRATEGIES ON CANOLA YIELD AND PARTIAL GROSS MARGIN IN SÃO BORJA, RS

Abstract

The objective of this study was to evaluate the growth, grain yield, and partial gross margin of canola subjected to urea rates and Azospirillum brasilense application strategies under field conditions in São Borja, Rio Grande do Sul, Brazil. Two independent field experiments were conducted in 2024 and 2025, each arranged in a randomized block design with three replications and a 3 × 3 factorial arrangement consisting of three urea rates (0, 75, and 150 kg ha⁻¹) and three A. brasilense application strategies, which differed between experiments. In Experiment 1 (2024), shoot green biomass, leaf area index, and grain yield were evaluated, whereas only grain yield was evaluated in Experiment 2 (2025). In 2024, urea rates and A. brasilense application strategies did not result in statistically detectable differences in the variables evaluated. In 2025, grain yield increased linearly with increasing urea rates, from 1,420 to 1,807 kg ha⁻¹ between 0 and 150 kg ha⁻¹ of urea, whereas no statistically detectable effect was observed for A. brasilense or the interaction between factors. Partial gross margin showed different numerical responses between the experiments: increasing urea rates reduced the margin in 2024, whereas the yield increase associated with urea application resulted in a numerical increase in 2025. The results indicate that canola response to urea differed between the two independent experiments and that economic outcomes depend on the relationship between yield response, input costs, and the environmental and nutritional conditions of each production environment.