Feasibility of storing canola at different moisture contents in silo bags under Canadian Prairie conditions

Silo bag is a recently introduced temporary grain storage system which is becoming more widely used in Western Canada. The goal of this study was to examine the conditions that would allow safe storage of canola, in silo bags, under Canadian Prairie weather conditions. Canola seed at three different moisture contents (m.c.) 8.9, 10.5 and 14.4% (wet basis), which represent dry, straight and damp moisture contents, were stored in silo bags for 40 weeks (from fall 2010 to summer 2011) in Winnipeg, Manitoba and analyzed to determine the quality changes in the stored canola. For each moisture content, three bags were tested, and each bag was loaded with approximately 20 t canola seeds with > 90% initial germination quality. Germination, free fatty acid value (FAV), and moisture content of canola seeds at seven locations within each silo bag were analysed every 2 weeks along with carbon dioxide (CO2) concentrations of intergranular air and temperature of canola seeds. For dry moisture canola (8.9 % m.c.), the germination was maintained above 90%, and FAV also stayed at safe storage levels during the 40-week storage. The germination of straight moisture (10.5% m.c.) canola was maintained at initial value in most parts of the silo bags, except the top layer. However, the germination of damp moisture (14.4% m.c.) canola dropped to below 80%, and FAV doubled its initial value within 8 weeks of storage. High levels of CO2 and localized hotspots in the damp moisture canola seeds indicated greater biological activity. Canola seeds, which were graded as Canada Grade 1 at the beginning of the storage, were considered to be Grade 1, Grade 2, and Feed Grade for the dry, straight and damp moisture canola seeds, respectively at the end of the 40-wk storage study.