Recommended best management practices
Before choosing to utilize silo bags, in addition to the economics, the following best management practices adapted from a list compiled by Purdue University Extension should be considered:
Corn, soybeans and wheat stored in silo bags should have moisture content at or below 15%, 13% and 12%, respectively. Sunflower and canola should be stored with moisture content below 10%. It is prudent to err on the conservative side and rather store drier than wetter grain, oilseeds and pulses.
Corn dried using a high temperature dryer should be cooled to within a few degrees of ambient temperature prior to bagging so that heat is not trapped in the bag when it is sealed. Otherwise condensation on the underside of the plastic lines could lead to fungal development and premature grain spoilage.
Silo bags should not be over loaded; most bags only stretch by about 10% and over filling could result in the bags breaking, especially when they are unloaded. Also, sufficient lengths of plastic liner at the ends are needed to properly seal the bags as filling is started and at the end.
Corn, soybeans and other crops should not be stored in the bags beyond the cool weather period, which for fall harvested crops in North America means no more than six months. Winter conditions in the U.S. Midwestern and Great Plains and Canadian Prairies will keep the grain fairly cool and slow down any biological activity. During spring warm-up when snow melts, water may leak into punctured bags and as temperatures rise biological activity such as the growth of fungi and insect pests will accelerate in damp grain.
Grain quality should be monitored regularly along each bag using CO2 sensing technology, and bags identified with increasing CO2 between bi-weekly readings should be designated for earlier unloading than bags with stable CO2 readings.
Bags with increasing CO2 should be sampled using a grain trier to determine the extent of water ingress or spoilage that can be detected near the surface. Punctured liner locations for sampling must be resealed after sampling and can be reused. Punctures must be patched using specially provided sealants and tapes (not duct tape) available from silo bag dealers.
Bags should be inspected frequently for damage of the liners by rodents. Note that snow cover can hide punctures and therefore snow should be cleared from the bags to effectively assess damage to the flexible liner.
Benefits of using silo bags
Reduced capital investment required compared to building permanent steel bins; estimated at about $60 to $80 per tonne ($1.50 to $2 per bushel) of stored grain.
Cost-effective alternative that can act as buffer storage estimating to cost $2.75 per tonne (7 cents per bushel) of grain stored.
Simplification of harvest logistics by providing flexible storage even along the edge of the field, especially when logistics to reach permanent storage is a constraint.
Easy means for on-farm segregation of commodities, thereby providing a suitable option for identity preservation of specialty grains.
Maintain grain moisture content during storage when a hermetic (air-tight) environment is maintained.
Disadvantages of using silo bags
Require special loading and unloading equipment, which first-time users will need to purchase or rent through fee-for-service providers.
Extra labor and time is needed to load and unload, and to monitor stored grain in silo bags.
Stored grain is more susceptible to negative influences from the environment, especially extreme weather.
Stored grain is vulnerable to damage from vermin and insect pests, thus protective measures and monitoring need to be in place.
Under U.S. warehouse licensing rules, silo bags are considered temporary storage and thus typically cannot be used for warehouse receipt of grain. Users should also check with their crop insurance agent regarding insurance coverage.
Stored grain cannot be aerated to control moisture movement, temperature changes, and fungi and insect development through cooling.
Silo bags can only be used once as they are cut open along the top during retrieval of grain. Used bag plastic needs to be disposed of properly, ideally by recycling.