Uso de bioestimulantes con herbicidas y sus efectos en la fitotoxicidad y rendimiento de soja

The use of biostimulants in combination with herbicides has been proposed as a strategy to mitigate the expression of phytotoxicity in field crops and to help maintain yield. However, crop responses may vary depending on environmental conditions, herbicide type, and management practices. In this context, the objective of this study was to evaluate the use of a biostimulant applied in mixture with herbicides and its effects on phytotoxicity, nodulation, and yield in soybean. The experiment was conducted at an experimental site located in the department of San José, Uruguay. A completely randomized design with seven treatments and five replications was used. Treatments consisted of the application of herbicides applied in post-emergence of the crop (fomesafen, S-metolaclor, and benazolin etil + fomesafen), applied alone and in combination with the biostimulant PROGEN Detox, as well as an untreated control. Crop phytotoxicity was evaluated at 5, 14, 30, and 45 days after application. Nodulation was assessed at reproductive stages R3–R5, and final yield was determined at harvest by sampling the experimental plots. Phytotoxicity data were analyzed using non-parametric tests, applying the Kruskal–Wallis test at each evaluation date and the Friedman test to account for variability among replications. Nodulation was analyzed using analysis of variance with a model that considered plant nesting within plots, complemented by non-parametric analyses for individual variables. Final yield was analyzed using analysis of variance. Initial phytotoxicity symptoms were observed in treatments including S-metolaclor; however, these symptoms were visual and transitory, with no persistence in later evaluations, and a progressive crop recovery was observed throughout the growing cycle. No statistically significant differences were detected in phytotoxicity between treatments with and without the biostimulant in subsequent evaluations. Likewise, no significant differences were found in nodulation or yield among treatments. In summary, under the evaluated conditions, the use of the biostimulant PROGEN Detox in mixture with herbicides did not generate differential effects on phytotoxicity, nodulation, or yield in soybean, highlighting the importance of environmental conditions and the crop’s physiological compensation capacity in the observed response.