Potencial fisiológico de sementes de soja em função de diferentes doses e fontes alternativas de potássio (bioinsumos)

Potassium is the second most important nutrient for soybeans. This nutrient is essential for growth, development, and increased seed quality. This study aimed to evaluate the physiological potential of soybean seeds subjected to different doses and alternative sources of potassium. The experiment was conducted in the experimental area of the State University of Goiás, South Campus, Ipameri University Unit. Seed production was carried out in the 2022/2023 harvest. The experimental design was in randomized blocks, in a 3x5 factorial scheme, with three potassium sources (KCl, Phonolite-F1, and Hydrothermalized Phonolite-FH2) and five doses (0; 50; 100; 150, and 200 kg ha-1). To evaluate the physiological quality of the seeds, germination and vigor tests were performed: first germination count, germination speed index, accelerated aging, electrical conductivity, tetrazolium, seedling length, 1000-seed mass, fresh and dry mass of seedlings. The mass of 1000 seeds with F1 and FH2 reached the maximum value with doses of 119 and 94 kg ha-1, respectively. The electrical conductivity test indicated high vigor, presenting values below 70 μS.cm-1. g-1. The fresh mass and total length of seedlings showed significant differences between the doses, fitting a quadratic regression, with a minimum point between 99 and 141 kg ha-1. Alternative potassium sources (Phonolite and Hydrothermalized Phonolite) showed comparable performance to KCl, becoming viable options for replacing the traditional potassium source and increasing doses positively influencing the dry mass of soybean seedlings.