Early potassium fertilization enhances physiological and health quality of soybean seeds

ABSTRACT Potassium fertilization plays a crucial role in optimizing soybean yield by enhancing seed vigor and reducing the incidence of pathogens. This study aimed to evaluate the physiological and health qualities of soybean seeds from cultivars grown under varying potassium chloride application rates and timing. We used a randomized block design in a split-split-plot arrangement, with three replications. Two soybean cultivars (Brasmax Olimpo IPRO and CZ 58B23 I2X) were planted in the main plots. In the subplots, three potassium application timings were tested: 100% early (30 days before sowing), 50% at sowing, and 50% at 30 days after emergence (DAE), and 100% at 30 DAE. The sub-subplots included five potassium rates (0, 50, 100, 150, and 200 kg K2O ha-1). Seed quality parameters assessed included thousand-seed mass, water content, seedling emergence, electrical conductivity, first germination count, germination percentage, shoot and root dry matter, accelerated aging, and pathogen incidence. The results showed that fertilization of Brasmax Olimpo IPRO with 200 kg K2O ha-1, either 100% early or 100% at 30 DAE, resulted in superior seed physiological and health quality.