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Managing Grain in Storage. Conditions that Lead to Storage Problems. Grain that is too wet Grain that is too warm Trying to hold grain too wet, too warm, too long Fines accumulations Uneven grain temperatures in storage Grain not checked often enough. Equilibrium MC of Soybeans (% wb ).
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Conditions that Lead to Storage Problems • Grain that is too wet • Grain that is too warm • Trying to hold grain too wet, too warm, too long • Fines accumulations • Uneven grain temperatures in storage • Grain not checked often enough
Equilibrium MC of Soybeans (% wb) Temperature Relative Humidity (%) (F) 60 70 80 90 32 11.8 13.7 16.2 19.8 40 11.5 13.5 16.0 19.6 50 11.2 13.2 15.7 19.4
Equilibrium MC of Corn (%wb) Temperature Relative Humidity (%) (F) 60 70 80 90 32 15.1 16.6 18.4 21.3 40 14.5 16.017.9 20.8 50 13.8 15.4 17.3 20.2
Allowable Storage Time for Shelled Corn (days) Temperature Corn Moisture (% wb) (F) 16 18 20 22 24 40 763 291 144 85 57 50 339 130 64 38 26 60 151 58 29 17 11 70 85 32 16 10 7 80 47 18 9 6 4
Aerate Stored Grain (Fall, Manual Control) • Use fans to force cool outdoor air through bins to cool stored grain. • This can be done manually by watching weather forecasts and turning fans on and off. • Run fans to cool the grain in about 10 to 15 deg F steps in the fall until the grain reaches 25 to 30 F. • Time to move a cooling front through grain depends mostly on the airflow per bu.
Warm Cool Measure exhaust temperature Cooling zone Cooling zone Cool Warm Fan Fan Positive pressure Negative pressure Movement of Cooling Zones During Aeration
Aerate Stored Grain (Automatic Controls) • It is important to know the algorithm, what the automatic control is supposed to do. • It is important to check the system to make sure the automatic control is doing what it’s supposed to be doing. • Automatic controls work, but they require a lot of bushels to be economically justified. • You can often do manually what the automatic controls are designed to do.
Aerate Stored Grain (Winter Management) • Once stored grain is cooled to 30F, not much drying is going to take place, and molds will grow very slowly. • Aerate as needed to maintain storage temperature, but fans can usually be shut off between aeration cycles. • Check grain regularly (frequency depends on grain condition) for signs and smells of mold and stored grain insects.
Cable Temperature sensor Temperature indicator Fan Permanently Installed Grain Temperature Cables
Aerate Stored Grain (Spring) • If grain isn’t cooled below 30F, there might not be a need to warm it in the spring. • If grain is cooled below 30F, it must be warmed in spring to prevent problems with condensation on the grain or frosting of equipment during summer. • During grain warming, fans must be left on until warming is complete. • Grain must be dry before the weather gets warm.
Aerate Stored Grain (Spring and Summer) • Grain must be dry. • Stored grain insects can be a problem, even in dry grain, if the temperature is too high. • Avoid warming the grain above 50F. • Avoid running aeration fans when the outdoor temp. is above 50F.
Crusted grain Moisture accumulation Cold grain Convection air currents Warm Grain Moisture Migration
Fines Management • Fines are pieces of broken grain, weed seeds, soil, and chaff that are smaller than whole kernels. • Fines are undesirable in stored grain because they: • Are easier for molds and insects to feed on. • Often have a higher moisture content than the whole grain. • Tend to accumulate in pockets. (more)
Fines Management (cont.) • Have a higher airflow resistance than whole grain. • If present in large enough quantities, they can lead to price discounts. • Clean grain before drying and storage. • Or use a grain spreader to distribute fines throughout the grain mass. • Or don’t distribute fines and core bins to remove fines.
Grain Spreaders or Distributors • Can be difficult to match with conveyor into storage and to bin diameter.
Work Safely Around Stored Grain! • Use proper respiratory protection around dusty and/or moldy grain. • Stay out of flowing grain. • Watch out for bridged grain. • Use fall protection when climbing bins or rail cars. • Fumigants are potentially dangerous chemicals.
For More Information… • Contact BillWilcke, phone 612-625-8205 or e-mailwilck001@umn.edu • See http://www.bbe.umn.edu/Post-Harvest_Handling_of_Crops • For information on fan selection, see Selecting Fans and Determining Airflow for Crop Drying, Cooling, and Storage, FO-5716. A fan selection computer program can be downloaded from the website. • For information on cooling hot grain, see Dryeration andIn-Storage Cooling for Corn Drying, ww-07356. • For information on dry grain storage, see MidWest Plan Service, www.mwps.org, AED-20, Managing Dry Grain in Storage.