Oilseed storage in hermetic enclosures: protecting quality and germination
Oleaginous seeds are more sensitive than cereal seeds to high temperatures, and also to oxygen content, which favors lipid oxidation and can reduce germination energy (an important factor for rapid seedling emergence) leaving no time for plant diseases to take hold. The preservation of germination capacity is ensured over a long period of time, provided that the water content of the products is sufficiently low (below the sorption equilibrium threshold of 65% RH).
Sorption equilibrium curve between water content (W.C.) of sunflower seed and air R.H. in seed mass.
Storing oilseed in a hermetically sealed enclosure under inert gas also helps limit loss of seed vigor if temperatures do not exceed 20-22°C, provided seed moisture is below 8%. For oleic sunflowers with a higher oil content than conventional varieties, the balance between the relative humidity of the ambient air and the water content of the seed is different. Hermetically sealed storage in an inert atmosphere is recommended for these oleic varieties to limit the risk of loss of vigor and even germination capacity in the event of long-term storage.
Marked difference in equilibrium moisture content at 65% RH (conservation threshold without risk to seed viability)
between an oil-rich and an oil-poor variety of oleic sunflower.