Revista Brasileira de Sementes
Print version ISSN 0101-3122
BERTI, Melissa; AHRENS, Dirk Cláudio and BEUSSO, Daniele Regina. Stationary drying of wheat seeds using petroleum liquified gas. Rev. bras. sementes [online]. 2005, vol.27, n.2, pp.81-86. ISSN 0101-3122. http://dx.doi.org/10.1590/S0101-31222005000200012.
The purpose of this study was to verify wheat seed physiological and physical quality while using petroleum liquified gas (LPG) for stationary drying and to determine the drying curve in comparison to the stationary drying in an oven. Wheat seeds, variety OR-I, with 15,3% initial water contents were dried down to 12,6%, in a stationary dryer with a perforated horizontal central tube. Samples were taken at 45 min. intervals of the seeds set in three different positions from the central cylinder (proximal, median and distal from the heat source), during the drying process. The physical seed quality was evaluated by water contents, weight of one thousand seeds, temperature of the seeds mass at different points. The physiological seed quality was evaluated by germination and vigor. The average speed obtained in the drying by gas was 0,9 percent points per hour (pph-1). The seeds were dried down from 15,3% to 12,6%, taking three hours, plus one more hour for cooling. The drying speed was reduced as the distance of the seeds from the central cylinder increased (at the proximal point to the heat source 1,00pph-1 and at the distal point 0,73pph-1) because the temperature of the seed mass was higher at the proximal point. The temperature of the seed mass increased gradually in the points closer to the heat source during the drying process. The seed physiological quality was assessed by tests of germination and vigor, which demonstrated the possibility of using petroleum liquefied gas in the drying process with the temperatures applied.
Keywords : water contents; temperature; germination; seedling emergence.