We dug into aggregated, real-world data contributed anonymously by FBN farmer members to investigate trends in corn harvest moisture levels.
There have been studies and debates by agronomists and researchers for years on the optimal moisture levels for corn at harvest. Here’s what the data we analyzed showed.
The standard moisture for corn is 15.5%, so when grain is delivered at greater than 15.5% grain moisture, the weight is adjusted down. (This reflects the remaining weight when the grain is dried to 15.5% moisture, losing water weight in the process.)
In contrast, when grain is delivered at grain moistures below 15.5%, you’re paid for the delivered weight because weights are not adjusted up to what the grain weighed when water content was higher.
With that in mind, the graph below shows corn yields that we observed at different harvest moistures (with yields above 15.5 percent grain moisture adjusted down to the 15.5% standard, and yields below 15.5 percent moisture left unadjusted).
At moistures above the standard, we generally see similar yields. But we also observed slightly lower yields between 15.5-18.5% moisture.
As expected, yield drops sharply below the standard moisture, as weight is lost when moisture is removed from the grain.
And, keep in mind that from the perspective of profitability, not just yield, you may incur drying costs for grain delivered at moistures above the standard.
More than 38% of acres harvested within the FBN network are at 15.5 - 18.5% moisture.
We also noticed a trend (though not a surprising one to us) that farmers tend to harvest at slower speeds when harvesting wetter corn.
The wetter the corn, the slower the harvest speed, though only slightly.
Typical corn harvest moistures also vary quite a bit by state, with wetter harvests further north.
FBN member farmers in northern and eastern Corn Belt states tend to harvest at 18-20% moisture, while those in western and southern Plains states harvest closer to the 15-18% moisture range.
The map below shows recent average corn harvest moisture levels by state.
There has been a slight trend for wetter harvests across the country in recent years, but the pattern is a fairly weak one, and there is substantial year-to-year variability.
Harvest moistures from 2013 and 2014 were the wettest of the past 7 years.