Securing soybean seed quality: the critical role of postharvest temperature and atmosphere management on vigor and longevity

BACKGROUND: High seed quality is a cornerstone of crop establishment and yield stability. However, newly harvested soybean (Glycine max) seeds often exhibit low germination vigor, posing a significant agronomic challenge. This study investigated the after-ripening behavior of freshly harvested soybean seeds and evaluated how storage temperature, humidity, and storage atmosphere influence seed germination, nutritional composition, and longevity. RESULTS: An optimal after-ripening window of 30-45 days (25 °C, 65% relative humidity (RH)) was identified for seeds to reach peak physiological quality. The effects of different environmental conditions were then quantified. Low temperature (15 °C) and a controlled atmosphere (nitrogen) were highly effective in preserving seed viability and longevity, significantly decelerating quality loss. Conversely, high temperature (35 °C) and high humidity (75% RH) conditions represented severe abiotic stress, causing a catastrophic and rapid loss of seed viability. CONCLUSION: Soybean after-ripening is strongly regulated by storage environment. Temperature was the dominant factor, while higher humidity accelerated deterioration and nitrogen-enriched storage delayed after-ripening and quality loss. These findings provide practical guidance for optimizing postharvest soybean storage, either to prolong seed longevity or to regulate the timing of after-ripening for subsequent use. © 2026 Society of Chemical Industry.