Superior corn yields start with a great stand. But as farmers grow more corn on corn, they face the challenges—cool, wet soils and potential for higher disease and insect pressure—that come with planting into higher levels of residue.

QUICK EMERGENCE

Kip Cullers placed first and second in the irrigated conventional tillage category and second in the irrigated ridge-till category in the National Corn Growers Association yield contest in 2006. Cullers says he looks for two things to get a good corn stand.

“I always plant a hybrid that’s fast out of the ground, and I always plant it with a seed treatment to protect it from wireworms, grubs and flea beetles,” he says.

With a winning yield of 347 bushels on his highest yielding contest plot and a low yield of 244 bushels per acre on his worst performing farm field, Cullers knows how to get a good stand and keep it growing.

In no-till fields, the Purdy, Mo., farmer runs trash whippers on the planter to move some of the residue. Cullers uses a variety of tillage methods, including no-till and conventional tillage. What he uses depends on the previous crop, he says. And since Cullers grows everything from vegetables to fescue, he has quite a range of planting conditions.

Cullers believes in no-till, but he also realizes tillage has its place. “I no-till but I’m not one of those guys that never tills. It just depends on the field conditions.”

In the western Corn Belt where the wind blows, University of Nebraska Extension agronomist Robert Klein recommends growers not to move crop residue. Instead, he suggests using no-till to conserve moisture within the field.

“The wind in the West likes to blow, so if we move residue out of the way, it can blow back over and cause a problem. If we can just cut through it, that’s preferable,” says Klein.

While many Corn Belt farmers favor no-till or strip-till, others still use cold steel. “Many of our producers value tillage that improves the seedbed, and, following soybeans, it’s still common here,” says Emerson Nafziger, Extension specialist at the University of Illinois.

“With more corn on corn, the amount of tillage has actually increased slightly.”

WATCH SEED PLACEMENT

Regardless of whether you use no-till, strip-till or conventional tillage, the real action is in seed placement and soil contact, says Nafziger.

“Our best bet still is good seed placement, and we know that when we see it,” adds Nafziger. “The seed has to be in a condition in the soil where it has every chance to come up at the same time as every other seed in the field.”

Complaints about poor emergence due to seed-quality problems are rare today, says Nafziger. He credits seed corn companies with stepping up quality control in production processing and the use of improved seed treatments.

PEST PRESSURES

“With the cooler, wetter soils you’ll find in both early planting and high-residue conditions, you’re going to have more insect pressure and disease pressure,” says Bruce Battles, agronomy marketing manager for Syngenta Seeds.

Syngenta offers a premium package called Cruiser Extreme 250. The package consists of Cruiser 250 (a seed-applied insecticide) coupled with Dynasty (a fungicide treatment that helps control rhizoctonia) and Maxim XL with a boosted rate of Apron to control pithium, fusarium and phytopthora soil-borne pathogens.

In replicated trials, Battles says, adding the extra fungicides to the seed treatment adds 4 to 5 bushels per acre to the bottom line, illustrating the importance of seed treatments.

“It’s not the type of situation where we get a yield response every single time. But we feel since we’re getting a yield response 67 percent of the time, that’s a pretty good investment in your crop.”

Syngenta officials also don’t recommend boosting plant population just because you’re planting corn on corn. “We believe you should put the stand out there and protect the stand you’ve got rather than expecting to lose several thousand seeds per acre before getting to your desired population,” adds Battles.

HYBRID SELECTION

Managing residue is a key component of continuous corn success. You have higher residue levels to contend with, plus Bt hybrids break down less readily than non-Bt hybrids. Steve Butzen, agronomy information manager for Pioneer, points out that finding a hybrid that performs in high residue also will help to optimize crop performance.

“When selecting hybrids for a corn-on-corn situation, I would be sure they have an acceptable high-residue suitability score. This rating includes stress emergence and resistance to leaf diseases and ear rots,” says Butzen. “To me, those are the most important factors.”

If there is more residue on the surface, the soil is likely to be cooler and wetter, which means you should employ tactics like strip-till to move residue and warm up the seedbed, he adds.

“The real secret to stand establishment in corn residue is either using strip-till or residue managers. That will help you get the soil warmed up in the seed zone and get better stands,” Butzen explains.

MANAGE RESIDUE AT HARVEST

A strong corn stand starts with setting up your combine correctly the previous fall, says Robert Klein, University of Nebraska Extension agronomist. By optimizing combine settings, you can better manage residue in continuous corn fields.

“The only thing you really want going through that combine is yellow ears. Anything else that goes through is chewed up and creates a mat,” says Klein. “Look at modifications like slowing down the gathering chain speed using beveled stripper plates and tapered stalk rollers.”

Klein explains that by managing your residue the previous fall, you’ll be more likely to have ideal planting conditions in the spring. He says the No. 1 thing to avoid is shredding the stalks, which would create an impenetrable mat and keep the soil wet and cold.

“We really like those knife-to-knife or flute-to-flute rollers where they pinch the stalk but don’t break it off, which helps the stalk to decay,” says Klein.

“Good residue management is critical and one of those things we really have to work for.”

© Copyright 2009 DTN
By Sherry Collins, Progressive Farmer Contributing Editor