Keeping grain in good condition
As harvest is nearing completion, piles of grain on the ground are becoming larger and more numerous. These piles, and the grain bins that are full, represent a good deal of money and investment. Unfortunately, some farmers have been known to not treat them with the respect they deserve. I can remember a co-worker making the analogy that if an equal value in dollar bills were stored in the same grain bin, the farmer would likely check them every day to make sure they’re still there and in good condition.
As has been stressed in this column and other resources, the key to the length of time you can safely store grain (allowable storage time, or AST) is a function of grain moisture and temperature. Tables with AST’s are available in various Extension publications, such as SDSU’s factsheet, ExEx1014, “Grain Drying Guidelines for a Wet Fall Harvest:” http://pubstorage.sdstate.edu/AgBio_Publications/articles/ExEx1014.pdf.
Farmers must realize that these AST’s make the assumption that the grain temperature will remain the same over the time of storage. If the grain is cool enough to stop any insect and/or microbial activity (below about 40 degrees F), it will likely remain that temperature unless it is quite wet (corn over 20 percent). If the grain is warm enough to allow insect or microbial activity however, it will generate heat and raise the temperature, reducing the AST.
This is why it is important to monitor grain moisture and temperature, as well as odor at least once per month during storage. If the grain moisture content and/or temperature is higher than ideal, the grain was immature at harvest and/or contains excessive fines, it should be checked more often than monthly. It is also recommended to cool grain with aeration whenever the air temperature is 10 or more degrees F lower than the grain temperature, until the grain temperature is down to about 25 degrees F.
If wet grain is planned to be stored past the time when temperatures begin to rise in the spring, it will need to be dried to moisture content levels recommended for long-term storage, corn – 13 percent, millet – 9 percent, sorghum – 13 percent, soybeans – 11 percent, non-oil sunflower – 10 percent, and oil sunflower – 8 percent.
Ken Hellevang, Professor and Extension Engineer at North Dakota State University recently shared concerns about the reliability of grain moisture meters when grain is cold. With grain moisture being so important in determining how long grain can safely be stored, accurate moisture readings are critical. Electronic moisture testers have been shown to produce erroneous readings when grain is cold. In short, the best recommendation is to collect a sample of the grain, put it immediately in a sealed container, and allow it to reach room temperature before measuring the moisture content.