As farmers wrap up this year’s harvest and auger in the last few bushels of grain into the bin, their attention will turn to managing that grain so it is of high quality when it is ready to sell at a later date. Properly storing grain can be tricky, as there are several factors that will determine how long it can be in storage including: grain quality, moisture content, and the quality of storage facilities.
Two major factors influencing grain storage are initial grain quality and moisture content. The past few weeks has seen pretty cooperative weather, but it can be important to not completely depend on the grain naturally drying in the field. If cooler weather or rain sets in, this can cause issues with grain quality and result in stalk rot development, making eventual harvest of a field difficult. There is some concern that this year’s stalks are already week, meaning we are also wishing for strong winds to stay away. Therefore, a big part of proper grain dry down is to do it mechanically. Post-harvest, grain should be dried down to the proper level based on your long term storage plan. Purdue recommends corn be quickly dried down to at least 15% moisture if it will be in storage for up to 6 months. Any longer than that, and corn grain should reach the 13% moisture mark. For soybeans, 13% moisture should be the desired moisture for storage up to 6 months, with 12% being the desired level for grain stored between 6 and 12 months, while grain stored over 1 year should reach 11% moisture. It is important to note that once we get beyond the 6 month mark in storage we are once again encountering warmer weather, which can be responsible for an increase in pests and mold. Thus it is important to reach these moisture levels prior to that point.
The quality of the grain that is being stored should also be considered. For poorer quality grain, it is recommended to dry down the grain an additional 1% of the levels mentioned above. This is because fines and trash in the grain provide a suitable environment for insects, and trashy grain will reduce air flow in the grain bin, leading to an increase in dry time and an increase in mold accumulation. To prevent this, all combine and grain handling equipment should be calibrated accordingly to reduce kernel breakage. These fines are likely to accumulate in the center of the bin, so equipment may be needed to mix in or remove these damaged kernels.
Temperature is also a factor, as it is important to reduce the possibility of any biological activity such as insects and mold. To accomplish this, grain would ideally be cooled down to 40 degrees by December. If you are unsure of your drying capabilities, the University of Minnesota has put together a helpful online app that allows users to enter their crop inputs, grain bin dimensions, and fan type. From this information the app will calculate airflow and pressure differences from different depths within the grain bin compared to what is actually needed when the bin is filled to different capacities. This app is available at: http://webapps.bbe.umn.edu/fans/ . Lastly, as always, when working around and in grain bins, always remember to work safely and be aware.