There remains grain corn to be harvested in some parts of Manitoba, due in some cases to high kernel moisture contents and immature crop. Corn in the field may dry about 0.3 to 0.5 percentage points per day during October; however, that decreases to 0.15 per day or less during November. The amount of drying in the field will depend on factors such as corn maturity, hybrid, moisture content, air temperature, relative humidity, solar radiation and wind speed.
Table 1: “Estimated” Corn Field Drying
However, what is interesting is regardless of kernel moisture content in November, if left standing the crop can dry down moisture contents below 20%. The following figure from MASC illustrates this point.
Figure 1: Grain Corn Moisture Content Change (1992)
Yield Loss. If the stalks stay standing and there isn’t much ear drop, snow cover or wildlife damage, the crop can get through the winter without much yield loss. However, notice the number of disclaimers in that sentence. Ear drop will vary by hybrid and environmental conditions as well as the amount of grain on the ear (smaller ears should stay attached better than larger ears). Stalk strength may have also been compromised this year due that early September frost event; although the cool temperatures did not kill the plant outright and only leaf material, the plant would have ‘scavenged’ resources from within itself, i.e. the stalk, to help with grain fill. This would lead to compromised stalk strength.
If winter conditions are cool without snow then corn will continue to dry and can be harvested throughout the winter.
If you do find yourself in the position of wanting to over winter your corn, please touch base with your local MASC agent.
Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist, MAFRD