Seed Storage Factors.
Many elements affect the viability of stored seeds. Two principal factors that we can control are seed initial moisture content and temperature of storage. We further assume that temperature and seed moisture remain constant during storage. Storage time is defined as the years of storage when 90% of the initial batch of seeds are still viable.
It can readily be shown that seeds stored in hermetic containers remain at constant moisture content. Seed storage data can then be simply reported as storage time verse temperature at constant seed moisture.
With the understanding that vapor pressure is the driving force for moisture transfer between a seed and its environment (osmosis). We can provide the same simplified reporting for seeds stored in controlled environment warehouses.
In these warehouses, the air temperature and relative humidity (rh) are constant. Total energy (enthalpy), total water content, and water vapor pressure are also constant. Seed moisture vapor pressure will equilibrate to the ambient air moisture vapor pressure. Or better yet, seeds should be dried to the proper moisture content before they are placed in the warehouse. Typical storage conditions for seeds are 50°F/50% rh. From the Harrington equations for equilibration data for corn, seed stored at 50°F/50% rh will be at 14% dry moisture content.
Further proof of this concept is shown in our book:
“Osmosis: The Molecular Theory”, 2013, a collection of papers by Larry D Howlett see http://htmdengineering.com/