ABSTRACT Sequential crops may be affected by herbicide residuals in the soil. In corn crop there are reports of problems when the crop is sown soon after application of ACCase-inhibiting herbicides. The aim of this study was to evaluate safety intervals for the application of ACCase-inhibiting herbicides before sowing corn in different soils. Two experiments were conducted in a greenhouse, and in the field conditions. In both, the experimental design were completely randomized in factorial scheme 6x4+1 (6 periods of application x 4 herbicides + 1 control) with five replications. The treatments were: haloxyfop-P-methyl (124.7 g ha-1), clethodim – formulation 1 (192 g ha-1), quizalofop-P-ethyl (100 g ha-1) and clethodim formulation 2 (192 g ha-1) in applications at 15, 10, 5, 3, 1 and 0 days before sowing in sandy and clayey soil. In the greenhouse, formulations based on clethodim were more safety in both types of soils, and safety intervals for clethodim-based herbicides were 5 days and greater than 15 days for quizalofop-P-ethyl and haloxyfop. Haloxyfop should not be applied on day of sowing in clay soil. In the field none of the treatments compromised the development and yield of the crop, even when applied on the day of sowing.

Resumo: O objetivo deste estudo foi avaliar a eficiência do teste de envelhecimento acelerado para determinar o potencial fisiológico de sementes de soja com diferentes tratamentos químicos; verificar a influência do tratamento de sementes após o armazenamento e analisar a concordância entre os métodos de envelhecimento acelerado com os resultados reais de armazenamento das sementes. O estudo foi dividido em dois experimentos, ambos com delineamento inteiramente casualizado, com quatro repetições. No primeiro experimento os tratamentos foram dispostos em esquema fatorial 3 x 2 x 3: três tratamento de sementes (imidacloprid + thiodicarb; fipronil + thiophanate methyl + pyraclostrobin; ausência de tratamento), dois níveis de vigor (alto; baixo) e três métodos de envelhecimento acelerado (tradicional; solução saturada de NaCl; sem envelhecimento) avaliando-se a germinação. No segundo experimento, os tratamentos foram dispostos em esquema fatorial 3 x 2 x 2: três tratamentos de sementes (imidacloprid + thiodicarb; fipronil + thiophanate methyl + pyraclostrobin; ausência de tratamento), dois níveis de vigor (alto; baixo), dois tempos de armazenamento (0 e 135 dias), avaliando-se a germinação e emergência de plântulas. Os métodos de envelhecimento acelerado foram eficientes para determinar o potencial fisiológico das sementes, em que, o NaCl apresentou melhores resultados. O potencial fisiológico das sementes de soja reduziu ao longo do armazenamento e a aplicação de produtos químicos no tratamento de sementes prejudicou as porcentagens de germinação e emergência, independente do ingrediente ativo utilizado. O método de envelhecimento acelerado com NaCl apresenta maior concordância com os resultados reais de armazenamento.

Abstract: This work evaluated the efficiency of accelerated aging test to determine the physiological potential in treated soybean seeds with fungicides and insecticides, in addition to analyzing the concordance between the results obtained by different accelerated aging methods with the actual results of the physiological quality in seeds after the storage. The study was divided into two experiments, both with entirely randomized delineation, with four replications. In the first experiment, seed germination was evaluated after imposing some treatments that were arranged in a 3 x 2 x 3 factorial scheme: seed treatment (imidacloprid + thiodicarb; fipronil + thiophanate methyl + pyraclostrobin; no treatment); vigor levels (high; low); and accelerated aging (traditional; saturated NaCl solution; no aging). In the second experiment, seedling emergence was evaluated after applying some treatments that were arranged in a 3 x 2 x 2 factorial scheme: seed treatment (imidacloprid + thiodicarb; fipronil + thiophanate methyl + pyraclostrobin; no treatment); vigor levels (high; low); storage time (0 and 135 days). The accelerated aging methods were efficient to determine the physiological potential of the seeds, in which, the NaCl method presented better results. The physiological potential of soybean seeds decreased throughout storage and the application of chemicals in seed treatment impaired the germination and emergence percentages, regardless of the active ingredient used. The accelerated aging method with NaCl presents greater agreement with the actual storage results.