C.O.R.N. Newsletter: 2025-15

Season 3, Episode 9 of Battle for the Belt is now available: https://www.youtube.com/watch?v=N595T0wzKA4

In episode 9, we discuss relative maturity adjustments for late-planted corn. Due to cold temperatures and wet conditions in April and May, planting delays are affecting different regions in the state. Planting date and hybrid selection have direct implications for corn yields.

Corn relative maturity is influenced by planting date. Selecting corn hybrids and adequate relative maturity is important and dependent on the target planting window. However, if the target planting window differs from the feasible date, adjustments can be considered. In our battle of the belt trial, we are studying five planting windows and four different relative maturities across three sites: 100-day, 107-day, 111-day, and 115-day (Figure 1). Adjustments in the hybrid’s relative maturity can influence yield potential. Usually, longer relative maturities are expected to yield better than their shorter counterparts. Planting a long relative maturity in the wrong environment can lead to frost damage in the fall, affecting yields.

Figure 1. ‘Battle for the Belt’ sites, planting date windows, and corn relative maturities.

For Western Ohio, 2024, yields were maximized with the second and third planting dates (April 16 and May 6). In both plantings, best yields were achieved with the 115-day hybrid (Figure 2). When planting was delayed to June 17, yields were drastically decreased and the short maturity hybrid yielded best (100-day), followed by hybrid maturities 111 and 107.

Figure 2. “Battle for the belt” – Western Ohio, corn results, 2024

For Northwest Ohio, 2024, the first planting date was delayed to the middle of May due to non-favorable weather conditions in April and early May. The best-yielding results were obtained with the second planting date, May 23 (Figure 3). For that planting date, relative maturities 100, 107, and 115 had comparable yields, with hybrid 111 yielding less. When the planting was delayed to June 23 at this site, yields decreased and hybrids 100, 115, and 111 yielded best.

Figure 3. “Battle for the belt” – Northwest Ohio, corn results, 2024.

For Northeast Ohio, 2024, the best yields were achieved with the second (May 3) and third (May 21) planting dates (Figure 4). On May 3, the best-yielding hybrid was the 115-day. For the May 21 planting, the best-yielding hybrid was the 100-day.

Figure 4. “Battle for the belt” – Northwest Ohio, corn results, 2024.

From our results in the past two years, planting date trends have been less consistent for corn, relative to soybean (not discussed in this article – to be discussed next). In general, across research sites, planting corn between mid-April and mid-May has been optimal. In all cases, interactions between planting dates and relative maturities have been documented – suggesting that hybrid maturity selection should be based on planting dates. Longer relative maturities have resulted in higher yields for early plantings. On the other hand, delayed plantings have often benefitted from shorter maturities (in late May or June). Early planting does not always result in higher yields; when planting conditions are not fit, delayed plantings can result in higher yields.

Figure 5. Yellow corn at the Northwest location (5/20/25).

Field & Crop Progress Updates

Corn at the Northwest and Western locations have not fully recovered from the rain and cool temperatures, continuing to have yellow coloration. Northwest Ohio has these symptoms exacerbated by having some of the coldest conditions in the state (Figure 5). As we drive across Ohio, this condition can be seen throughout the state.

Soybean stages from the first two planting dates range from VE to V2 across locations, with Western being slightly ahead (V2), despite being planted three weeks later than the other sites (Table 1, Figure 6). Corn stages range from V1 in planting date two to V4 in planting date one, with Western being slightly ahead of the other locations also (Table 1, Figure 7). Western is located in the southern part of the state, allowing for more growing degree day (GDD) accumulation, from which producers can maximize yield by planting longer maturity hybrids in early plantings, as discussed in Figure 2.

Figure 6. Soybean planting date one (March 27^th) and two (April 17^th) at the Northwest Station (Top) and planting date one (April 18^th) at the Western Station (Bottom). Pictured on 5/20/25 and 5/21/25, respectively.

Figure 7. Corn planting date one (March 27^th) and two (April 16^th) at the Northwest Station (Top) and planting date one (April 18^th) at the Western Station (Bottom). Pictured on 5/20/25 and 5/21/25, respectively..

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

If you would like to learn more, check out our research updates through C.O.R.N. article updates and YouTube Videos this growing season! You can find the full video playlist of Battle for the Belt on the Ohio State Agronomy YouTube channel