LONG-TERM HERMETIC STORAGE OF BARLEY IN PVC-COVERED CONCRETE PLATFORMS UNDER MEDITERRANEAN CONDITIONS

A method for the bulk storage of barley in the open air under Mediterranean conditions was developed. A large (75 x 25 m) concrete platform with low walls was filled with barley and covered with a PVC overliner and a polyethylene underliner. The barley formed a pile of 4018 tonnes with a peak 7 m high and was stored for 34 months under hermetic seal. Periodic monitoring was carried out to determine temperature fluctuations, intergranular gas composition, insect infestation, and grain quality parameters. Ambient temperatures were shown to create temperature gradients in the upper layers, and moisture migration occurred towards the peak of the grain bulk. However, the resulting spoilage by moulds was limited to 0.22% weight loss on an annual basis. An additional 0.12% loss due to insect damage, and spillage resulted in an annual storage loss of 0.34%. Possible solutions to this problem were discussed. The platform successfully protected the grain against insect, bird, and rodent attack and provided safe storage during the rainy season. At the end of storage the PVC overliner, which had been used continuously since 1988, remained with low gas-permeability, retained its mechanical characteristics and was suitable for reuse.