If you want the biggest yield in your corn, you can’t wait until it’s in V12 to start thinking about how to manage stressors. Setting your corn up for success as early as possible can pay significant dividends later.
Early-season stressors, particularly drought stress, can quietly undermine your stand establishment, root development and early growth. However, understanding these stressors and what you can do about them can help you maximize yield and bottom line.
Let’s review the primary early-season stressors to look out for.
Drought stress in corn
You know that water is crucial for optimized yields. But you may not realize that the timing, duration and crop stage during drought conditions are just as important as the total amount of water lost.
Drought stress in corn can affect many aspects of the plant, including nodal root growth. Studies have shown that nodal roots start growing just ¾” below the soil’s surface. If your soil is excessively dry within that zone, your corn will have a difficult time standing. You may not even notice things are bad until V5.
To determine the severity of corn heat stress, look at leaf rolling. The earlier in the day you see leaf rolling, the worse the drought stress is. Mild leaf rolling is a way for the corn plant to reduce leaf surface area and limit transpiration. But if rolling becomes sustained and starts earlier each day, especially before 10 a.m., it’s a sign that root-zone moisture is insufficient, and the plant is limiting photosynthesis to conserve energy.1
While drought stress in the early and mid-vegetation stages won’t have as much impact on corn yield as it will after V13, it can reduce the number of kernel rows if drought stress is significant from V5-V7.2
For additional ways to help your crop bounce back from drought stress, check out this BASF article for practical tips.
Excessive water
While too little water can negatively impact corn yields, too much of it can be just as detrimental. Excessive water stress from germination to V6 deprives the root of oxygen, slowing root growth. Just 48 hours of saturated soil can damage seedlings, especially in warm conditions, leading to poor stand establishment and fungal diseases.
Even if your corn survives, flooding can leach off nitrogen and possibly lead to nutrient losses and deficiencies. Yield losses of 10-50% have been reported in corn that’s flooded for longer than two days.3
Early-season nutrient deficiencies
Nutrient loss early in the season can often go unnoticed until symptoms appear later in vegetative growth. While the top four nutrients get most of the attention (nitrogen, phosphorus, sulfur and zinc), other micronutrient deficiencies can also limit your yield potential.
By V4–V6, nutrient demand increases rapidly. If deficiencies persist, root and stalk development suffer. Timely scouting, tissue tests and rescue applications, particularly sidedress nitrogen, can prevent long-term yield reductions for early-season nutrient stress.
Soil compaction
If roots struggle to penetrate the soil, they won’t grow and access the water and nutrients they need. Compaction often occurs from traffic on wet, early-season soils, when the soil structure is most vulnerable.
Planting into compact soil can limit water movement through the soil and create conditions for runoff. Emerging corn can often be stunted when trying to grow in compacted soil.4
Try to avoid tilling in wet fields, restrict your travel lanes and manage your soils to improve organic matter content.
Improper planting methods
When seeds aren’t planted at the proper depths or have poor seed-to-soil contact, you’re setting yourself up for uneven emergence and weak early stands. Uneven emergence can create competition between early and late-emerging corn. This can lead to a 5-20% yield loss depending on the extent of the emergence gap.5
Cold or wet at planting time only makes it worse, slowing down development and leaving those young plants more vulnerable to everything from nutrient loss to compaction and disease.
Management solutions
So, what can you do to minimize the effects of early-season stress in corn?
Here are four key areas to focus on:
- Optimize seed placement: Uniform and consistent depth, planting into good moisture to ensure even emergence and strong stands.
- Improve soil structure: Reduce tillage compaction, minimize field traffic and consider cover crops to boost infiltration, aeration and root growth.
- Manage water availability: Use drainage or irrigation to avoid extremes (saturated or bone-dry) and monitor soil moisture proactively.
- Enhance root development: Manage early nutrients, and choose hybrids with strong early vigor and root architecture.
Taking action before stress becomes a visible problem can mean the difference between a good harvest and a great one.
Experts are available to help you make your management decisions. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative.
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Endnotes
- Sharma, Vasudha, Seth Naeve, and Jeff Coulter. “Early Season Drought Effects on Corn and Soybean.” University of Minnesota Extension, 16 June 2023. https://blog-crop-news.extension.umn.edu/2021/06/early-season-drought-effects-on-corn.html
- Nielsen, R. L. (Bob). “Ear Size Determination in Corn.” Purdue University Agronomy Department, June 2023. http://www.kingcorn.org/news/timeless/EarSize.html
- Lindsey, Alexander, Peter Thomison, and Steve Culman. “Young Corn with Wet Feet: What Can We Expect?” Ohio State University Extension, June 2018. https://agcrops.osu.edu/newsletter/corn-newsletter/2018-15/young-corn-wet-feet-what-can-we-expect
- Idowu, John, and Sangu Angadi. Understanding and Managing Soil Compaction in Agricultural Fields. Circular 672, New Mexico State University Cooperative Extension Service, Nov. 2013. https://pubs.nmsu.edu/_circulars/CR672/
- Carter, Paul R., et al. Requirements for Uniform Germination and Emergence in Corn. NCH-36, Purdue University Cooperative Extension Service, 1992. https://www.extension.purdue.edu/extmedia/nch/nch-36.html
