What is the secret to high corn yields? To start, you need to figure out what could be limiting your yields. Only then can you can figure out how to address those factors. Below, you can consult our list of 12 proven corn production practices, and read our 6 tips to ensure a good stand. New research is also out that many corn growers will find useful. It turns out that variable-rate seeding has shown few benefits. And when seeding, it’s better to plant corn deeper than too shallow. Not everyone will be able to get above the 300 bushel-per-acre level, but below is useful guidance on how to make the most of every seed.
Purdue University Extension Recommendations
Tom J Bechman of Indiana Prairie Farmer spoke with Bob Nielsen, a Purdue University Extension corn specialist about how get high corn yields. Nielsen suggests two things:
- Identify your yield-limiting factors.
- Determine solutions for those factors.
Sounds fairly straight forward. Nielsen explains.
“Once you plant corn, that crop’s yield potential is exposed to a whole array of yield-limiting factors. These yield-limiting factors threaten to reduce yield potential.”
Identifying Yield-Limiting Factors
Nielsen suggests addressing each field individually for potential problems. Problems could be anything- wet or dry soil, compaction, insects, pests, diseases, weather conditions or even management ability.
“If you fail to identify and diagnose yield-limiting factors, some agronomic decisions will be no more accurate than throwing darts while blindfolded,” Nielsen says.
Basically, if you aren’t able to identify what’s affecting your yields, it’s impossible to address it. Sometimes this can be challenging. It requires basic agronomic knowledge and skill. Nielsen suggests brushing up on your knowledge of the corn life cycle, so you know the proper timing of key decisions.
These days, there are many new tools that can be used to determine yield-limiting factors. Aerial photos and yield maps can help you see the bigger picture, and might identify issues you can’t see scouting on the ground.
Once you’ve identified problems, you can begin working to mitigate them. The solutions could be fairly simple- like adjusting depth settings, changing nutrient amounts, or timing of nitrogen application. Or, the solution might be more complex and long-term- like investing in irrigation for dry fields.
A very important thing to remember, Nielsen suggests, is to make sure that you actually have a problem that needs a solution.
“Look for solutions which are well-documented with reliable research. Farmer testimonials or data from one or two trials isn’t good documentation.”
“Some solutions people want to sell you simply aren’t needed in your field. That’s why you need to know what’s holding down yields before you make key input decisions.”
Nielsen says that taking a “shotgun” approach could cause you to spend money on solving problems that you don’t have. For example, limited field trials have shown that sulfur helps some corn yields. If you just apply sulfur because someone recommends it, and you don’t compare strips, you’ll never know whether or not that was money and time well spent.
Proven Production Practices
What are some tried-and-true corn production practices? Corn & Soybean digest published some proven production practices last March from Peter Thomison and Steve Culman of Ohio State University. Drops in net returns forces producers to reduce input costs, so try these twelve tips to improve your corn performance.
- Be sure to know the yield potential of your fields. Keep track of yield history, productivity and soil type.
- Choose high-yield hybrids, that have been consistent in multiple locations for a number of years. When planting no-till or reduced tillage after corn, select hybrids with high ratings for foliar and stalk rot diseases. Select high-yielding Bt rootworm resistant hybrids if there’s potential for the western corn rootworm damage.
- Stay on top of your pest and weed control.
- Get planting finished by May 10. Avoid early planting on soils with poor drainage. If soil is dry, it’s possible to plant before the optimal date. If planting late, consider using corn borer resistant Bt hybrids.
- Do all you can to help stands establish. Adjust seed depth as necessary, and make sure your planter is is good working order. Operate your planter at the optimum speed.
- Follow seeding rate recommendations.
- Apply the most economical nitrogen. Select an application method that minimizes N loss.
- Test your soil. You can use it to adjust pH and help guide better P and K fertilization.
- Only till when necessary and conditions are right.
- Control the field traffic, which can unnecessarily compact soils.
- Rotate crops. Corn after soybeans will typically yield 10-15% more than corn after corn.
- Monitor your fields for yield-limiting problems throughout the entire growing season.
Tips to Get a Good Stand
Eric Larson of Delta Farm Press also shared six tips for planting high-yielding corn from Mississippi State University. The key is to improve your chances of achieving successful corn stands.
- Measure your soil before planting. Shoot for 55 degrees at planting depth early in the morning.
- Don’t plant in wet fields. Your planter won’t be as precise, and tractor tires will compact the soil more, inhibiting seedling root growth.
- Plant soils that drain well first. Heavy or clay soils can hold onto moisture longer.
- Don’t knock down your beds is you can help it. Raised beds protect seedlings from overly wet or cool soil.
- Seed depth. For proper root development, corn should be planted between 1.5 and 2 inches deep. Planting deeper may be necessary if soil is very dry.
- Watch your planter ground speed. You really want even spacing and don’t want to rush it. Going too fast cause seeds to roll and bounce more during planting.
Variable-Rate Corn Seeding
What about variable-rate corn seeding? There’s been a lot of speculation about this practice increasing yields. But hold on. New research out of Purdue University shows that variable-rate seeding has little benefit. Gil Gullickson of Successful Farming reports that most of the time, the practice isn’t worth the investment.
Variable seeding means that you change your seeding rate depending on the optimal seed population to specific field areas. Bob Nielsen, Purdue Extension agronomist says that most of the time, in their studies, they haven’t seen much of a response.
The one area that is an exception is dry fields at risk for drought. Rolling back planting rates there has proven effective.
Getting Above the 300 Bushel-Per-Acre Level
Nielsen says that corn growers have to do a lot more than just plant extremely high amounts of seed to get above the 300 Bushel-per-acre level. High populations don’t necessarily guarantee super-sized yields. Up to 240 or 250 bushels per acre, there’s no proof that yield takes off. It plateaus at a population of around 30,000. Right now, according to Nielsen, there’s not enough data on the optimal plant populations for yields above 250 bushels-per-acre do draw any reliable conclusions.
But even if you’re not reaching for astronomical yields, farmers should try to make every seed count. Nielsen suggests doing planter stand counts in every field, every year.
“If you don’t do that, then you are throwing darts,” he says.
Better to Plant Deep
Tom J Bechman of Indiana Prairie Farmer reports that more data has confirmed it- it’s better to plant deep than too shallow. The evidence is from Jim Schwartz, who runs Beck’s Practical Farm Research (PFR) project. According to their 2018 PFR book, which contains results from multiple trials in multiple Midwestern locations over four years, there’s a measurable advantage to planting deeper.
They found a 6-bushel advantage to planting at a depth of 2 inches vs. planting at a depth of 1.5 inches. And, in some of their tested locations, planting at a depth of 2.5 inches yielded a half a bushel more than planting at 2 inches.
It’s important to note, that each year is different, and weather conditions vary. So there are not hard-and-fast rules about the absolute optimal planting depth.
One thing that the PFR project did show, however, was the negative impact of shallow planting.
The four-year average for 1 inch is nearly 15 bushels less than the 1.5-inch depth, and more than 20 bushels under both 2- and 2.5-inch planting depths. Planting at 1 inch was a bushel per acre worse than planting at 1.5 inches, but planting at a half inch was a whopping 65 bushels worse. That should encourage you to make sure even one planter unit isn’t placing seed too shallow.
The conclusion from the PFR project? Better to err on the side of planting deep than too shallow.
What have we learned? Plant deep. Do planter stand counts. Be skeptical of variable-rate seeding, unless it’s in drier, drought-prone fields. Take some time to determine what factors might be impacting your yields, and then do what you can to address those problems. With corn prices fairly low, we need to make every seed count.
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