A warm spell in January is a good time to check stored grain.
“Search for small changes that are indicators of potential problems,” advises Ken Hellevang, North Dakota State University Extension Service agricultural engineer. “The early 2012 harvest and warm fall increase the likelihood of storage problems.”
The value of the grain stored in a 25,000-bushel bin is about $175,000 at a corn market price of $7 per bushel, $350,000 for soybeans at $14 per bushel and $200,000 for wheat at $8 per bushel.
“At those prices, monitoring and managing the stored grain to prevent problems is worth your time,” Hellevang says.
Check to assure that the grain temperature is at 20 to 30 degrees in northern states and below 40 degrees in warmer regions of the country. Grain stores best when cool and dry. The allowable storage time approximately doubles for each 10 degrees that the grain is cooled. Also, insects are dormant below about 50 degrees.
Temperature cables are an excellent tool to measure the grain temperature, but they only measure the temperature of the grain next to the sensor. Grain is a very good insulator, so warm or hot grain just a few feet from the sensor may not be detected.
Operate the aeration fan to cool the grain to the recommended temperature if needed. Aeration is not necessary if the grain is at the appropriate temperature.
Bin vents may frost or ice over if fans are operated when the outdoor air temperature is near or below freezing, which may damage the bin roof. Open or unlatch the fill or access cover during fan operation to serve as a pressure relief valve. Cover the aeration fan when it is not operating to prevent pests and moisture in the form of snow, fog and rain from entering the bin.
Hellevang recommends collecting grain samples and checking the moisture content to assure that the moisture content is at the desired level. However, most grain moisture meters are not accurate at grain temperatures below about 40 degrees, so when the grain is cold, it should be placed in a sealed container, such as a plastic bag, and warmed to room temperature before checking the moisture content.
At temperatures above 40 degrees, the meter reading must be adjusted based on the grain temperature unless the meter measures the grain temperature and automatically adjusts the reading. Check the operators manual for the meter to determine the correct procedures to obtain an accurate value.
Because insects are dormant at colder temperatures, warm the grain samples to room temperature and place the grain on a white cloth to inspect for insect infestations. Grain fumigants will not control an insect infestation adequately if some of the grain is cold. The fumigant does not volatize in cool grain adequately, and insects in cool grain near the edge of a “hot spot” may have limited metabolic activity, resulting in poor control.
Also, if the fumigant does not volatize, it remains in the grain and becomes a health hazard for people handling the grain. Cooling the grain is the best method to control insect infestations during the winter. Insects are dormant below about 50 degrees, and some insects can be killed by cooling the grain to below freezing and keeping it at that temperature for a few weeks.
Hellevang suggests recording the grain temperature and conditions observed to help spot trends in the condition of the stored grain. Insect infestations and grain spoilage generate heat, so noting temperature trends is important.