Battle for the Belt: Season 3, Episode 25: Corn Relative Maturity and Dry Down under Dry Conditions

Author(s): Taylor Dill, Maria Kessler, Diego Miranda, Laura Lindsey, Osler Ortez

Season 3, Episode 25 of Battle for the Belt is now available: https://www.youtube.com/watch?v=21IpRTOGvss

In Episode 25, we join Taylor Dill, the Battle for the Belt PhD student, to look at corn hybrid differences during dry down this season.

Growth, development, and dry down in corn differ based on relative maturity. In our study, growth stage differences are rarely observed in vegetative stages but are visible during reproductive stages and dry down. In Battle for the Belt we have four relative maturities, 100-day, 107-day, 111-day, and 115-day. Earlier relative maturities normally reach tasseling/silking, days before later maturing hybrids and can reach physiological maturity (or black layer) more quickly than a full season corn hybrid. Black layer is usually reached at around 30% moisture but can also vary by hybrid. In our study, we have seen that the 100-day hybrid will reach black layer at a lower moisture content than full season hybrids (Figure 1). Full season hybrids also have higher moisture at harvest and can take longer to dry down. In Northwest and Northeast Ohio, the later planted 115-day is often about 25% or more moisture at harvest.

Figure 1. The 100-day (R6) and 115-day (R5) (planted 4/16) relative maturities at the Northwest Agricultural Research Station.

In dry down, the earlier the plant reaches physiological maturity, the faster the dry down and the later the plant reaches maturity, the slower the dry down. This effect signals why later maturities have higher harvest moisture. However, environmental conditions can change the rate of dry down. In warm, dry, and windy conditions, like we are currently facing, dry down would happen more quickly. If the crop was planted later than normal, growing degree compression can occur and reach physiological maturity in less growing degree days than labeled for, which is exacerbated by hot weather. When these dry conditions persist, the crop will cannibalize the stalk to reallocate nutrients to the ear to finish filling out kernels, which can create crop standability issues. As we approach harvest, we recommend to scout fields and evaluate stalk strength and lodging presence to prioritize harvesting fields that have lower stalk quality. For more information on overall corn dry down please refer to “Field Drydown of Mature Corn Grain” by Bob Nielsen.

What’s happening in the field?

Figure 2. Drought Monitor published September 11th, 2025. Retrieved from https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?OH

Each location around the state continues to be dry. None of the locations received rainfall last week. The Northwest location is in a moderate drought, while Western and Wooster are abnormally dry according to the most recent drought monitor update on September 11^th (Figure 2).

At each location, the first two planting dates of corn have reached R6 with some variability in the hybrids. The last planting date at each location has not reached R5 yet and kernel size will likely be affected by the dry weather. Tar spot was found at the Northwest location in the fourth and fifth planting dates (5/29 and 6/24). The disease was not widespread, with less than 5% leaf area coverage on the ear leaf. The late planting dates already show firing up in the bottom leaves and dry down.

The first planting date of soybean (3/27) at Wooster has reached R7, where at least one pod on the plant has attained harvest color. Most planting dates and locations are at R6 or full seed. The fifth planting date at all locations is still in the seed fill stage (R5). Senescence is already apparent in the third and fourth planting dates at all locations. Table 1 summarizes environmental conditions and stages across sites and planting dates.

Table 1. Precipitation, soil temperature, average air temperature, and cumulative GDDs at the Western Agricultural Research Station, the Northwest Agricultural Research Station, and Wooster Campus. Weather data retrieved from: https://weather.cfaes.osu.edu/.

Keep following the ‘Battle for the Belt’ this growing season to learn more and get further updates! You can find the full video playlist of Battle for the Belt on the Ohio State Agronomy YouTube channel.