Managing Corn for Greater Yield Potential: Insights From the 2025 NCGA National Corn Yield Contest

Since the introduction of hybrid corn nearly a century ago, corn productivity improvements have continued through the present day. Over the last 20 years, U.S. corn yield has increased by an average of 2.0 bu/acre per year. These gains have resulted from breeding for increased yield potential, introducing transgenic traits to help protect yield, and agronomic management that has allowed yield potential to be more fully realized.

As growers strive for greater corn yields, the National Corn Growers Association National Corn Yield Contest provides a benchmark for yields that are attainable when environmental conditions and agronomic management are optimized.

The 2025 growing season started with widespread drought conditions from the previous season lingering into the spring, but abundant rainfall during the summer largely broke the drought during the growing season. The USDA estimated average yield for the U.S. was 186 bu/acre, a new record high. At the state level, Wisconsin, South Dakota, and all three I-states posted record high yields, as did Virginia, South Carolina, and Georgia.

In the 2025 NCGA National Corn Yield Contest, 511 entries exceeded 300 bu/acre, a total second only to 2024 when 655 entries achieved this yield level (Figure 1). Fourteen states set new records for number of 300 bu/acre entries (Table 1). Contest entries over 300 bu/acre were recorded in a total of 41 states in 2025, which topped the previous record of 36 states in 2024.

The 2025 contest was noteworthy because of how geographically distributed the entries over 300 bu/acre were. In previous years, it has been common for a particular state or cluster of states to account for a large proportion of the highest yielding entries. For example, in the 2024 contest, Iowa alone produced 115 entries over 300 bu/acre, with Illinois close behind at 99, and Michigan with 53. In prior years, Nebraska has been a hot spot of high yield corn with nearly 100 entries topping 300 bu/acre in both 2021 and 2022. In the 2025 contest, the state with the most 300 bu/acre entries was Illinois with 51, followed by Indiana with 39, and Ohio with 31. No other state had more than 30.

States that saw a substantial increase in the number of 300 bu/acre entries in 2025 compared to 2024 were mostly outside of the central Corn Belt, including Alabama, Idaho, New York, Oregon, Pennsylvania, Tennessee, Texas, and Utah. High yield entry numbers were mostly down from 2024 in the Corn Belt states, sharply so in some cases.

Pioneer^® brand products were used in 197 NCGA National Corn Yield Contest entries that exceeded 300 bu/acre in 2025, as well as 13 national level winners and 215 state level winners.

State level winners included a total of 80 different Pioneer brand products from 65 different hybrid families ranging from 74 to 120 CRM (Appendix).

Yields exceeding 300 bu/acre have been achieved using Pioneer brand products from 100 different hybrid families over the past five years, ranging from 91 to 120 CRM. The top-performing Pioneer hybrid families in the National Corn Yield Contest are shown in Table 2. The Pioneer brand P13777 hybrid family had the most 300 bu/acre entries in 2025, with the P14830 and P1742 families both in the top three for the third year in a row.

Top performers in the NCGA yield contest not only have produced corn yields much higher than the current U.S. average; they have also achieved a higher rate of yield gain over time. Over the past 20 years, U.S. corn yields have increased at a rate of 2.0 bu/acre per year while winning yields in the non-irrigated yield contest classes have increased by 4.6 bu/acre per year (Figure 2A). Winning yields in the irrigated yield contest classes have increased at an even higher rate of 6.0 bu/acre per year.

The yield trend in the irrigated classes has been much more erratic, however. This is partly attributable to the smaller number of irrigated classes (and thus smaller number of winners) compared to non-irrigated classes, but it is mostly due to ultra-high yields (>450 bu/acre) reported by a small number of contest participants in the irrigated classes beginning around 2013. Yields reported for these entries have been far beyond those achieved by any other participants in the contest over the past decade and have had the effect of dramatically increasing the yield averages for winners in the irrigated classes as well as year-to-year variability. When all entries associated with these individuals are removed from the dataset, the yield trendline for the irrigated classes changes considerably (Figure 2B). The yield trend becomes much more linear (R2 value increases from 0.44 to 0.76) and the rate of increase drops to only 2.7 bu/acre/year, which is still greater than the national average, but is considerably lower than that of the non-irrigated contest classes.

What is most interesting about this analysis, however; is that – with the ultra-high yield outliers removed – the trendlines for the irrigated and non-irrigated classes converge. From 2002 to 2013, there is a consistent yield gap between the irrigated and non-irrigated classes of around 20-40 bu/acre. From 2014 onward though, this yield gap essentially disappears.

Water availability is a major yield-limiting factor in corn; its importance to corn yield is reflected in the fact that the National Corn Yield Contest has always maintained separate classes for irrigated and non-irrigated entries. Contest entries grown under irrigation are able to eliminate (or at least minimize) water availability as a yield-limiting factor, while non-irrigated entries are not. Contest entries that rise to the top of the ranks in the non-irrigated classes would presumably come from locations where rainfall during the growing season was sufficiently abundant to minimize water stress on the crop. However, the persistence of a yield gap between irrigated and non-irrigated class winners over much of the yield contest’s history suggests that, even under the best rainfed scenarios, water availability was still limiting to corn yield.

Drought tolerance has been a major focus of corn breeding programs for decades and corn breeders continue to drive improvements today. A noteworthy step forward in drought tolerance in corn came with the introduction of Pioneer^® brand Optimum^® AQUAmax^® corn hybrids in 2011. It’s possible that the closure of the yield gap between irrigated and non-irrigated class winners over the past decade is at least partly due to an improved ability of modern corn hybrids to endure transient periods of drought stress without a substantial impact on yield.

Contest fields are planted with the same corn hybrids available to everyone and are subject to the same growing conditions, which suggests that management practices are playing a key role in capturing more yield potential. The following sections will discuss management practices employed in contest entries yielding above 300 bu/acre.

Plant Population

One of the most critical factors in achieving high corn yields is establishing a sufficient population density to allow a hybrid to maximize its yield potential. Historically, population density has been the main driver of yield gain in corn – improvement of corn hybrid genetics for superior stress tolerance has allowed hybrids to be planted at higher plant populations and produce greater yields.

Harvest populations in National Corn Yield Contest entries over 300 bu/acre from 2021 through 2025 are shown in Figure 3.

The average harvest population over this period was 35,300 plants/acre, well above the USDA average plant population of 28,800 plants/acre, as would be expected for high-yielding environments. However, yields over 300 bu/acre were achieved over a wide range of populations, from 23,000 to 51,000 plants/acre, demonstrating that exceptionally high populations are not necessarily a prerequisite for high yields. Average harvest populations for high-yield entries in both the irrigated and non-irrigated classes have trended slightly lower over the past decade (Figure 4). Although population density is important in establishing the yield potential of a corn crop, it is just one of many factors that determine yield.

Planting Date

High-yielding contest plots are usually planted as early as practical for their geography. Early planting lengthens the growing season and, more importantly, moves pollination earlier. When silking, pollination and early ear fill are accomplished in June or early July, heat and moisture stress effects can be reduced.

The range of planting dates for contest entries exceeding 300 bu/acre in several states is shown in Figure 5, as well as the mid-point of corn planting progress according to USDA NASS. Average planting dates for 300 bu/acre entries in 2025 ranged from April 20 to May 10. The 2025 contest had several high-yield entries planted in mid- to late-May and even early June, demonstrating that high yields can still be achieved under favorable conditions if planting is not delayed for too long. However, the odds of achieving high yields are generally better with earlier planting.

Row Spacing

The vast majority of corn acres in the U.S. are currently planted in 30-inch rows, accounting for around 80% of corn production. Among high yield contest entries, this proportion is even greater, with over 90% in 30-inch rows (Figure 6). Row spacings narrower than the current standard of 30 inches have been a source of interest as a way to achieve greater yields, particularly with higher seeding rates. However, research has generally not shown a consistent yield benefit to narrower rows outside of the northern Corn Belt (Jeschke, 2018).

Crop Rotation

Rotating crops is one of the practices most often recommended to keep yields consistently high. Rotation can break damaging insect and disease cycles that lower crop yields. Including crops like soybean or alfalfa in the rotation can reduce the amount of nitrogen required in the following corn crop. A majority of the fields in the 300 bu/acre entries were planted to a crop other than corn the previous growing season (Figure 7). The rotation effect is a yield increase associated with crop rotation compared to continuous corn even when all limiting factors appear to have been controlled or adequately supplied in the continuous corn. This yield increase has averaged about 5 to 15 percent in research studies but has generally been less under high-yield conditions (Butzen, 2012). Rotated corn is generally better able to tolerate yield-limiting stresses than continuous corn; however, yield contest results clearly show that high yields can be achieved in continuous corn production.

Tillage

Around one third of the high yield entries in the NCGA contest in 2025 used conventional tillage, with the other 2/3 using no-tillage or some form of reduced tillage (Figure 8).

Over the past decade, tillage practices among high yield contest entries have shifted toward reduced tillage, with the percent of conventional tillage entries declining and the percent of no-till and strip-till entries increasing. Tillage practices varied considerably by state (Figure 9). Idaho had the highest proportion of conventional tillage entries, followed by Ohio, Kansas, and Illinois. Virginia, Pennsylvania, and Indiana had the most reduced and no tillage.

Nitrogen Rates

Corn grain removes approximately 0.67 lbs of nitrogen per bushel harvested, and stover production requires about 0.45 lbs of nitrogen for each bushel of grain produced (IPNI, 2014). This means that the total N needed for a 300 bu/acre corn crop is around 336 lbs/acre. Only a portion of this amount needs to be supplied by N fertilizer; N is also supplied by the soil through mineralization of soil organic matter. On highly productive soils, N mineralization will often supply the majority of N needed by the crop. Credits can be taken for previous legume crops, manure applications, and N in irrigation water. Nitrogen application rates of entries exceeding 300 bu/acre are shown in Figure 10. Numbers are based on 384 entries that reported N application rates and did not include any manure applications.

Nitrogen application rates of 300 bu/acre entries varied greatly, but the majority were in the range of 200 to 300 lbs/acre (Figure 10). As corn yield increases, more N is removed from the soil; however, N application rates do not necessarily need to increase to support high yields. Climatic conditions that favor high yield will also tend to increase the amount of N a corn crop obtains from the soil through increased mineralization of organic N and improved root growth. Total nitrogen applied in high yield entries has trended downward in recent years. In the 2016 contest, over half of high yield entries had over 300 lbs/acre of N applied, compared to less than 30% of entries in 2025.

Nitrogen Timing

Timing of N fertilizer applications can be just as important as application rate. The less time there is between N application and crop uptake, the less likely N loss from the soil will occur and limit crop yield. Nitrogen uptake by the corn plant peaks during the rapid growth phase of vegetative development between V12 and VT (tasseling). However, the N requirement is high beginning at V6 and extending to the R5 (early dent) stage of grain development.

Timing of N fertilizer applications in 300 bu/acre entries is shown in Figure 11. Less than 20% included fall-applied N. Many applied N before or at planting. Over 70% of 300 bu/acre entries included some form of in-season nitrogen, either side-dressed or applied with irrigation.

Nitrogen Management Class

A new feature of the NCGA National Corn Yield Contest beginning in 2023 was the addition of the Nitrogen Management Class (Class J). Entrants in this class are required to limit total nitrogen applications from non-field sources to 180 lbs/acre of actual nitrogen applied. This class is limited to 100 total entrants. Rules for this class also place limits based on previous crop, with only fields planted to corn, soybean, wheat, or wheat/soybean double crop eligible for entry.

The Nitrogen Management Class had 30 entries reporting yield in 2025. Of these 30 entries, 4 were able to top 300 bu/acre while applying no more than 180 lbs/acre of N. This works out to 13% of Nitrogen Management Class entries exceeding 300 bu/acre, compared to 19% of contest participants overall in 2025.

Secondary and Micronutrients

Around 30% of 300 bu/acre entries reported applying one or more secondary or micronutrients. Sulfur (S) was the most commonly applied nutrient, followed by zinc (Zn), and boron (B), and a smaller number of entries included magnesium (Mg), manganese (Mn), or copper (Cu). Micronutrients are sufficient in many soils to meet crop needs. However, some sandy soils and other low organic matter soils are naturally deficient in micronutrients, and high pH soils may reduce their availability (Butzen and Jeschke, 2022). Additionally, as yields increase, micronutrient removal increases as well, potentially causing deficiencies.

2025 NCGA National Corn Yield Contest state-level winners (1st, 2nd and 3rd place) using Pioneer^® brand products.