As commodity prices decline, it is tempting to let corn dry in the field instead of harvesting early and drying it on the farm or paying drying cost at the elevator. This article discusses the three top reasons to harvest your corn between 25-20 percent moisture. Those reasons are: phantom yield loss, harvest loss, and fall operations.
Phantom Yield Loss
This the loss of dry matter from the kernel. Seed is a living breathing organism that respires and uses its energy reserves over time. High humidity and temperature cause seed to respire at a higher rate. As seed is on the ear drying down it is in a very humid environment within the husk. Phantom yield loss is worse yet if corn dries down, is rewetted by rain and humid weather, then initiates sprouting which hurts quality, test weight and overall yield.
A Purdue study proved that yield losses of 0.6 percent-1.6 percent per point of moisture can occur in corn drying in the field (1). A later study by the University of Nebraska Lincoln minimized the significance of phantom yield loss (2). Though an elusive topic, from field trials and farmer experience and my experience, I believe phantom yield loss contributes 0.6 percent plus or minus yield loss per point of moisture and is a contributor to the yield loss observed in the field dry down of corn among other factors.
When the corn continues to dry and die in the field there is increased butt shelling at the stripper plates and ear loss at the header during corn harvest. Stalk integrity is less so there can be more stalk and root lodging as well as ear drop prior to running the combine through the field. This all means less bushels in the grain tank and increased volunteer corn the following year and also decreased harvest efficiency which can add fuel expense and lost time. Timely corn harvest may also mean less ear mold development because ear molds enter the plant at pollination and multiply in the humid dry down conditions of grain drying in the field.
If the elevator charges 3¢ per point of moisture per bushel (plus shrink), it would cost 21¢ per bushel to dry corn from 22 percent to 15 percent which is $42/acre at 200-bushel corn. At $3.25/bushel corn price it takes 13 bushels to pay for drying. It is very likely in this scenario that you could lose 10+ B.U./A. bushels per acre by letting the corn dry in the field. Further reasoning to justify harvest at 25-20 percent moisture can be made by considering adverse weather/wind/rain during this time along with the other benefits mentioned above that come with a timely harvest.