Late planting, a cool season and fall weather have conspired to push corn harvest into winter months in some geographies. The University of Wisconsin has studied these phenomena in the past ~25 years and I’ll try to summarize their findings so our customers have an idea of what to expect. The biggest question is dry down and Table 1 below is the best graphic representation of what you can expect as we move from fall to winter harvest. The table does not correspond well with our typical ideas that temperature, dry air and wind are necessary to dry corn. From plot work earlier in my career I have first-hand experience that once the crop goes through one or more hard freezes in December and January, it will get very near storage moisture with no real “drying days” taking place. In conversations with growers I used the term “freeze drying” for lack of better terminology.
Other considerations have to be field losses. UW has a stark contrast of data in Table 2, showing two successive seasons, probably the best and worst case scenarios, having corn in the field through the winter. Losses can occur from ear drop, lodging, ear rot or molds and wildlife feeding. In the case of the 2000 crop year, there was very heavy snowfall in the winter leading to lodging, ear drop and problems with harvestability. Note the yield increases from March to April in the 2000 crop year after the snow melted. The winter following the 2001 crop year had atypically light snowfall and the yield “hit” was minimal.
At this moment the Midwest is in a wet weather pattern, which would suggest a higher than average snowfall winter. Though I don’t want to be the bearer of negative news, you should however use a realistic field loss number such as the “Mean” of the 2000 and 2001 seasons. As you can see in the table above, storage in the field is not free.