Although it is not necessarily a common issue that we tend to worry about in this area, it does happen; that issue being snow accumulation occurring before crops are harvested. Obviously, this is not a new issue for those who may be dealing with snow covered crops but let this serve as a reminder of some considerations for harvesting crops this time of year.
One of the most important drawbacks of harvesting a crop this far past prime harvest season is that there will be a yield reduction. A study was done by the University of Wisconsin on the average yield loss in corn, when left in the field through winter. The study was reported on a monthly basis and showed that corn that was left in the field until January or February averaged a yield loss of 35%, per month. Now there are a few factors to consider for yield loss. One of the major factors is lodging. Lodging, or breakage of the stalk below the ear or pod, results in harvesting difficulties, pest, and disease problems, as well as grain loss due to ear or pod drop. Another factor resulting in yield reduction is the grain getting wet and then freezing. Repeated freezing and thawing can be problematic, especially in soybeans. Soybeans are prone to pod split and seed shatter. In corn, the wet husks can stick to the ear, leading to mold concerns and difficulty cleaning the grain properly. Additionally, leaving the grain out in the field leaves it open to wildlife feeding. Wildlife feeding, along with the other mentioned yield reducing factors compounded together can lead to significant yield losses.
Asides from yield loss, another issue that comes up when harvesting grain this time of year is the stress it can put on the equipment. It is important to get the combine settings right when harvesting frozen grain. It is also important to take care of preventative maintenance, as well as fixing appropriate repairs before running the combine through a frozen field. Combines can run in those conditions but running through a frozen and snowy field is not the easiest on them when looking at wear and tear.
Another important factor to consider is the soil. When you run a combine and a grain cart over wet, cold soil, compaction and rutting will happen. It is best to be patient and wait for a time when either the soil is frozen enough to be on, or the soil is dry enough to reduce compaction chances. The more likely of those situations is the soil freezing, as rarely do we have dry soils in the winter. Compacting and rutting the soil will result in problems for many years down the road. Out of all of the other impacts of winter grain harvest, the impact on the soil should be the one that you give the most consideration to. Severe compaction of your soil, as a result of attempts to harvest a corn or soybean field, likely with large yield losses already, can really hurt the productivity of the soil.
There is a choice to be made: try to salvage what yield you can this year by getting out in rough field conditions or wait for the ground to freeze and then harvest the crop, with minimal impact on the soil. Be patient and be willing to wait for the right conditions to get grain harvested and be willing to accept the hit on yield. Yes, a hit on yield is never easy to take, but a hit on long term field productivity is an even harder hit. Obviously, the situation calls for you to choose between the lesser of the evils, so while it may be something you have to deal with this year, have it in mind to do what you need to do to avoid the situation in the future.