Field effectiveness of gaseous ozone storage in alleviating damage to aged soybean seeds

Ozonation is a promising method for maintaining seed quality. However, the ability of ozone to preserve the quality of aged seeds, which have already deteriorated, is still open to question. This study evaluated the effectiveness of ozone in alleviating ageing soybean seed damage and also the economic feasibility of ozone technology under field conditions. Samples under ozonation storage (they were stored in open containers and woven sacks) were compared with those stored under conventional storage conditions (they were stored in woven bags without ozonation). Ozonated samples were exposed to 150 g h-1 of ozone gas for three hours a day for a six month storage period. All samples (with and without ozonation) were stored at 18 +/- 5 degrees C and 50 +/- 5% relative humidity. Observations were conducted every month with regard to the seeds germination percentage, vigour index, moisture content, protein and free fatty acids. The results showed that ozonation has the potential to increase the viability of aged soybean seeds for up to 5 months. However, the decrease in the protein and free fatty acids levels in the ozonated seeds occurred more rapidly than in the control. Moreover, no significant difference was found between the ozonated seeds in open containers and sacks during storage, except for their moisture content. Ozone application on aged soybean seeds was found to be financially feasible with an ratio of revenue to cost value of 1.73, an return on investment of 74.63% and a payback period of 1.34 years.