Early-Season Growth and Development Impact on Corn Yield in North Dakota

• Quantify the impact of early-season soil temperature and early-season management practices on corn yield in North Dakota.
• Compare the performance of two Pioneer^® brand corn products with differing early stress-emergence ratings under these diverse spring growing conditions.

• A 2-year field research study was conducted as part of the Pioneer Crop Management Research Awards (CMRA) Program with Dr. Joel Ransom at North Dakota State University.
• Field experiments were established in 2015 near Prosper, ND, and in 2016 near Casselton, ND.
• Treatments were combinations of planting dates, Pioneer brand corn products (differing in maturity and stress emergence rating), and early-season management practices, including nitrogen (N) fertilization timing and mulch.

Planting Dates:

• » April 23 and May 22 in 2015
• » May 2 and May 24 in 2016

Hybrid/Brand¹:

• » P8640AM™ (AM, LL, RR2), 86 CRM, stress emergence rating⁴ = 5
• » P9526AM™ (AM, LL, RR2), 95 CRM, stress emergence rating = 6

Early-Season Management Practices:

• » 0 N (non-fertilized check)
• » 150 lbs N at planting (fertilized check)
• » 150 lbs N at planting + 18-36-0 liquid fertilizer with seed
• » 150 lbs N at planting + clear plastic mulch for 3 wks after planting
• » 150 lbs N at planting + straw mulch for 3 wks after planting
• » 150 lbs N broadcast 3 wks after emergence
• » 150 lbs N broadcast 6 wks after emergence
• » 150 lbs N broadcast 9 wks after emergence

• Corn yields averaged over all treatments were 175 and 225 bu/acre in 2015 and 2016, respectively. These yields were well above the state-wide average and the yields in 2016 were considered exceptional.

Planting Dates

• Planting date did not significantly affect corn yield in either year (Figure 1).
• Though the recommended planting date in North Dakota is May 1st, there was frost damage on the emerged leaves of the early-planted corn both years. This damage may have negated the potential benefit from earlier planting.

Early-Season Management Practices (Continued):

• Only the treatment with 18-36-0 applied in-furrow differed significantly from other fertilized treatments and only in 2015. The yield reduction was associated with a lower plant population in this treatment and was most noticeable at the early planting date (Table 2).
• Applying liquid fertilizer with the seed is a commonly recommended practice, as it places nutrients close to the roots of the developing seedling.
• Reduced emergence with this treatment in 2015 may have resulted from too much salt near the seed combined with other conditions unfavorable for emergence (cold soils and a wet soil surface). Only a slight stand reduction occurred at the later planting date with this treatment in 2015, and there was no negative effect in 2016 regardless of planting date.
• Warming the soil with plastic mulch or keeping it cooler with straw mulch had a measurable effect on earlyseason growth rate (data not shown); although, there was no significant impact on grain yield in either year as a result of these treatments (Table 1).

Early-season management can be critical to establishing a foundation for high-yield potential in corn. The current recommended optimum planting period for corn in North Dakota is May 1 to May 20. Yield did not significantly differ between the two planting dates in either year. The lack of response to earlier planting may be associated with frost damage to the earlier-planted treatments. Though corn recovers well from frost that does not damage the growing point, the leaf damage may have delayed plant development to be similar to that of corn planted at the later date.

Table 2. Effect of early-season management at two planting dates on plant population averaged over hybrids, 2015.

Hybrid selection is important to maximizing yield in a given environment. The two corn products included in this work had slightly different stress emergence ratings and nine days difference in relative maturity. Though we observed greater early growth with P9526AM™, this did not translate to higher yield in 2015 due to early-season frost damage. Under more favorable growing conditions in 2016, the later-maturing hybrid was able to significantly out-yield the earlier-maturing hybrid. This difference could not be solely attributed to vigorous early emergence, as the more stress tolerant hybrid was later maturing and had inherently greater yield potential.

In favorable growing seasons with soils like those of the experimental sites in 2015 and 2016 with high levels of N mineralization and native fertility, there is no yield penalty for delaying the application of nitrogen up to nine weeks after planting. Unfortunately, these environments are not typical of most soils and growing seasons in North Dakota. Other research has shown the value of relatively late applications of nitrogen applied as a rescue treatment when there is a high level of nitrogen loss earlier in the season.

Adding fertilizer with the seed at planting can negatively affect plant population under stressful conditions for germination and emergence. Providing some separation between the seed and the fertilizer may help mitigate the risk of stand reduction.

*Research conducted as a part of the Pioneer Crop Management Research Awards (CMRA) Program. This program provides funds for agronomic and precision farming studies by university and USDA cooperators throughout North America. The awards extend for up to four years and address crop management information needs of Pioneer agronomists and customers, and Pioneer sales professionals.