Tricks to Increase Yields
Yes, you can still squeeze a few more bushels of corn and soybeans out of your fields. A project at Kansas State University (KSU) is pointing the way.
Researchers are testing advanced management practices to benefit both high-yielding corn and soybeans. Results so far provide an interesting contrast in how the two crops convert sunlight and nutrients into grain, and also show promise for better yields ahead.
Nutrients for soybeans
Soybeans fix nitrogen (N) on their root nodules to provide about 70% of the requirement. That’s why, for high yields, it’s important to implement best practices for an effective inoculation process at planting, says Ignacio Ciampitti, KSU Extension crop systems specialist and project leader.
To obtain the remaining 30% of the N they need, soybeans must draw from existing soil resources. Sometimes they respond to applied N, but research results have been mixed at best.
Ciampitti thinks two things will likely change the way we understand and apply fertilizer to soybeans.
- Interaction between soybean varieties and nutrients. “High-yield soybeans need more nitrogen than common soybeans. Up to now, many high-yield systems and research projects have not been based on the newest genetics,” he says.
- Timing of N applications. Soybeans continue to make grain later in the season than corn. Especially in high-yield situations, soybeans need N later. By midsummer when corn is finished uptaking nitrogen, soybeans aren’t.
“Low-yield soybeans will get the nitrogen from the leaves through the nutrient remobilization process. High-yield soybeans are drawing from soil and plant reserves,” says Ciampitti.
“What we need to do is understand when the nodulation process is impacted or reduced. What are the main factors affecting this process? Then, we need to investigate whether nitrogen application at those times can produce more bushels,” he says.
Increasing stress tolerance and prolonging green leaf area during pod fill are also important for high soybean yields. That’s where chemical applications that protect the leaf canopy will help, he says.
For corn, added nutrients are needed to get consistently high yields. The payoff doesn’t happen in straight-line fashion in every field, every year, though.
For instance, the KSU control plots use standard practices that include:
• 30-inch rows
• 30,000 plants per acre
• Minimal nitrogen applications
• No secondary nutrients or micronutrients
• No fungicides or insecticides
Other plots received more inputs and increasing levels of intensification – more fertilizer, narrow rows, higher plant populations (36,000 per acre for corn), and fungicide/insecticide applications.
During the project’s first year in 2014, no yield advantage resulted from the extra inputs. All the plots, from high input to low, yielded between 226 bushels and 231 bushels per acre.
Then in 2015, fields that received an additional 150 pounds of N per acre yielded 28% more than fields that didn’t. Yields maxed out in the plots with the most intensive management (36,000 plants per acre, added micronutrients, and fungicides).
“This was a well-fertilized field. So in the first year, the corn was getting plenty of nutrients without adding more,” Ciampitti says.
He now believes that maximum corn yield is a complex interaction between the stage of crop development and the availability of nutrients at specific times. That will be the focus of future research.
Soybeans respond more than corn to narrow rows. As a smaller plant with less biomass, it takes soybeans longer to fill the row and to capture the maximum available sunlight for photosynthesis.
Corn in 15-inch rows at the 10-leaf stage of growth intercepts about 15% more sunlight than 30-inch rows, explains Ciampitti.
At the same stage of vegetative growth, narrow-row soybeans have a light interception advantage of about 20% compared with wide rows. Narrow rows give the added bonus of more shade for weed control.
“Narrow rows and higher plant populations also mean the plants have to compete harder, and they grow faster,” says Ciampitti.
There’s one catch to narrow-row soybeans, though. Narrow rows can aggravate fields infested with white mold inoculum.
“White mold loves heavy dews,” says Daren Mueller, Iowa State University Extension plant pathologist. The early-forming canopy of narrow rows can reduce air circulation, thereby, helping white mold to gain a foothold in these fields.
The first two years of this high-yield study give good indication that better yields are coming. Narrow rows alone improved soybean yields by 30% in 2015, says Ciampitti. Soybeans that got all the extra inputs – more fertility, higher plant population, and fungicide/insecticide treatments – yielded 20 bushels an acre more than in standard practice for both irrigated and dryland situations.
3 corn tips for 2017
Busy putting the finishing touches on your 2017 corn strategy? Consider three factors.
Think about disease resistance. If you were a plant breeder devising disease-resistant hybrids, 2016 and 2016 have provided a great environment. Much foliar disease resulted in corn, including northern corn leaf blight, southern rust, and gray leaf spot.
Fungicides, of course, are excellent tools for managing in-season foliar fungal diseases. Just don’t count on them as your sole management option. Disease-resistant hybrids are also excellent management tools.
“Some hybrids can handle disease a lot better,” says Jeff Hartz, marketing director for Wyffels Hybrids.
Carefully eye economy corn. You may see economy corn on the market that often consists of firms blending high-germination corn with lower-germination corn. It’s a way to cut seed costs, but you can get what you pay for, especially if too much low-germ product is blended.
Make sure these products meet the germination standards you’ll need, adds Hartz.
Don’t forget about European corn borer. Think European corn borers are no longer a problem? They’re still there and lying in wait if you don’t manage for them.
“They are definitely not extinct,” Hartz says. “If you don’t use the trait, you’d better be willing to scout in season for them.”