Based on the size of Minnesota's corn and soybean crops and the kinds of questions I heard this fall, I anticipate some potential storage problems this winter.
Some corn was placed into silos or other unaerated storage structures at 17 to 19% moisture. In this moisture range, the bacteria that cause fermentation do not grow very well, but the molds that cause spoilage do. This corn is at high risk of spoilage and action must be taken soon. Options include the following:
Some dry grain is also stored in unaerated piles or structures. This grain has a lower risk of spoilage than wet grain, but considering our above-average fall temperatures, moisture migration is likely in this grain. Problems are especially likely in peaked piles. Moisture migration occurs when the temperature at the center of a grain pile is warmer than grain at the outer edges, and it results in an area of wet grain at the top center of the pile. Managers of unaerated stored grain should check it frequently (every week or two) by looking for signs of moisture accumulation and mold at the top of the bin or pile. It would also be helpful to probe the grain to measure its temperature at several depths and locations. The grain should be moved at the first sign of mold or heating to prevent major spoilage losses.
We'll undoubtedly get questions about using screw-in aerators to keep piles of grain in condition. These devices consist of a tiny fan mounted on a tube that is about six-foot long and has screw threads on the bottom so it can be screwed into grain. They can provide some air movement through a hundred or so bushels of grain at a time. These aerators can be helpful in cooling a small hot spot, but they are not very effective for cooling large, deep piles of grain.
In summary, any grain that was stored wet or was stored in unaerated structures needs to be watched carefully this winter and some action needs to be taken before spring.