Test Plot Roundup

February 13, 2009 06:35 AM

Focus On Seed Quality

In 2008, we wrapped up our multi-year plot effort studying seed quality and the impact seed size and shape have on vigor and emergence. The bulk of the data was gathered from replicated plots evaluating five seed sizes planted by one planter. Rounding out the data were scores captured by sending seed samples gathered from other non-seed-related plots to a trusted testing lab.

For the past three years, the seed for our seed quality plot was provided from the same lot and production field. Since different seed sizes and shapes are sourced from different areas of the cob, our seeds could have come from the same ears, assuring similarities within the seed's potential.

"In the past, round seed has been the easier seed to plant," says Farm Journal Field Agronomist Ken Ferrie. "But the technology in planters has changed to the point that we can now handle all seed sizes with success."
Even so, Ferrie encourages farmers to know as much as possible about the quality standards seed companies set.

"Quality is job No. 1, and it's right up there with safety," explains Gary Lawrance, quality testing manager for Pioneer Hi-Bred. "All [who work] in seed production at Pioneer have quality on their minds 100% of the time."
Quality standards and procedures provide reassurance in the overall strength of the industry, but it's not a guarantee all seed is rated equal or will maintain its condition.

Seed scores.
The standard germination test listed on the bag by seed companies is based on a warm germination test. Knowing that most farmers don't always have the good fortune to plant in ideal conditions, we looked at other scores, as well. In addition to warm germination, we also tested for cold germination, saturated cold germination and accelerated aging score.

Saturated cold germination predicts emergence when seed is planted in cold wet conditions. The accelerated aging test measures plant vigor while predicting emergence and storability.

"You don't want to always focus on warm germination scores," Ferrie says. "This plot expanded the view to other scores to see if all seed is created equal. We've found that the accelerated aging results are a good indicator of plant emergence. Strong plant emergence tends to lead to higher populations and, in turn, better yields."

The best accelerated aging score and highest emergence counts went to the seed with the highest-quality scores.

"In 2008 with this determinant hybrid, the strongest stands yielded better, which indicated population was the limiting factor," Ferrie says. "The highest population then yielded the best. The other accelerated aging scores weren't bad, but one was superior. You'd be happy there was 200 bu. until you realized there was 218 bu."

Our results from the multiple years indicate yield advantage was in line with the highest seed quality. Seed quality had a closer correlation with yield than seed size.

"We aren't saying one size seed isn't as good as another," Ferrie says. "If you have the same seed test results, size is irrelevant. The main decision driver for seed selection is the genetics in that seed."

By comparing seed test results with yield, we have observed damaged seeds are held back. "Be aware that seed with severe pericarp damage carries a higher risk," Ferrie says. "We see 100 or more seed tests a year from farmers, and it's consistent that severe pericarp damage is most prevalent in round seed."

The testing lab attributes this to round seed having an exposed germ. Flat seed has a more protected germ, where the germ is tucked within a pronounced indentation.

Pericarp damage can be particularly risky if you're using starter fertilizer in the seed furrow.

In general, Ferrie says that 80% of the seed tests he has reviewed point to excellent seed quality. That quality is primarily a reflection of the supplier's quality control measures and the weather conditions during the seed production year.

"We encourage all farmers with leftover unopened bags of seed to return them through the company's sales channel," says Pioneer's Lawrance. "Treated seed is riskier to store on-farm, and any returned seed will be retested and resorted before it's put back into the supply channel."

Lawrance offers these suggestions to maintain seed condition: Seed should be stored in a clean, cool and dry environment where there is no risk of rodent damage. When handling seed, guard against any impact that can cause physical damage to the seed.

If you are unfamiliar with your seed source, your supplier doesn't answer your questions or you find your seed to be suspect, Ferrie suggests reserving a sample. Fill a gallon-sized plastic bag at planting and store it in the freezer.

"Worst-case scenario, keep the sample in the freezer until the coast is clear and then you can throw it away," he says. "But if you run into trouble, you can send it in for testing."

Nematode Management

We jumped into the deep end of the pool to study nematode control in corn. With limited control options and the high potential damage from the pest, we've spent multiple crop years trying to zero in on the most effective control, especially in tough spots.

In 2008, our test plot was placed in a field with high populations of lesion, stunt and dagger nematodes that reoccur in specific zones. We know the exact location of those hot spots from yield maps and GPS coordinates from previous test plots.

"This is the seventh nematode plot in corn we've had," Ferrie says.

Corn nematode pressure can be reduced with crop rotation, tillage when nematodes are feeding and the use of organophosphates.

The most recent plot tested Counter, N-Hibit HB and ProAct. Counter is a labeled insecticide nematicide for use in the planter hopper. N-Hibit HB is an in-field application and mixed in the planter's hopper boxes. ProAct is a foliar-applied protein product that provides a compatible tank mix with postemergence herbicides, fungicides and insecticides.

The plot protocol included all possible combinations of the three treatments—in addition to the check—with no measurable success.

"In these nematode hot spots, we couldn't make a difference," Ferrie says. "Even with the three-way combination of all products, we didn't get movement in the corn yields."

Unfortunately, the disappointment isn't new. "This has been the story on corn nematodes. The nematode zones reappear every year," he explains.

Despite the frustration, Ferrie says there has been some success under certain conditions. "We've had a good response at controlling nematodes in the sandy soils that are under central pivot," he says. "We'll apply Furadan close to nematode feeding, and that so far has provided the best results."

Rootworms Under Pressure
Even with triple-stacked hybrids, some farmers are deploying more insect control. In high rootworm pressure areas, farmers are applying a soil insecticide when planting a trait corn.

Our plots, located in central Illinois, are on farms with varying soil types and rootworm pressures. In fields with strong pressures, we've applied either granular Force or liquid Force.

"With three years of data, I believe a realistic response to this application is 5 bu. to 7 bu.," Ferrie explains. "One of our cooperating test plot farmers had fields posting a 2 bu. to an 11 bu. response per acre.

"The soil insecticide provides extra control," he adds. "We aren't sure what it is, but it could be secondary pests or better rootworm feeding control."

For the first time, in 2008, we took a 16-row John Deere planter outfitted with the Central Insecticide System that applies liquid Force to the field. Liquid Force costs $18 to $20 an acre.

"The John Deere planter is another method for getting insecticide on," Ferrie says. "It's user-friendly because you can load it for a longer planting time without having to push a pallet of insecticide around."
In Ferrie's experience, applying insecticide to rootworm refuge consistently boosts yields. However, he cautions that the profitability is dependent on the price of corn.

"When corn is above $3.50, the numbers change on whether you'll get your money back for treating the corn with an insecticide," he says.

For example, a 5 bu. increase at $3.50 corn price doesn't cover the cost of the insecticide. "The key to this approach is realizing that this isn't going to perform uniformly in every case," he adds. "Farmers have accepted that."

You can e-mail Margy Fischer at mfischer@farmjournal.com.

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