Test Plot Roundup: Hybrids, Corn Nematodes, Row Spacing and Starter Additives

March 12, 2011 12:42 PM

In 2010, the Farm Journal Test Plots program harvested its 19th year of third-party, independent demonstration research. From soybean row spacing–the longest running study—to evaluating controls for emerging pests such as corn nematodes, the test plots head to the field each season to provide farmers with research they can apply to their own fields. Here’s a look at four of the topics: fixed and flex hybrids, corn nematode controls, row spacing and starter additives.

Responsive Hybrid Management

Out in the field, Farm Journal Field Agronomist Ken Ferrie has witnessed how stress affects different hybrids. Stress can be caused by water management, lack of nitrogen, disease or plant density. To learn how to maximize yields, Ferrie has 12 years of plots looking at population and hybrids.

"In my experience, all hybrids have a considerable ability to flex forward when population is low. However, in our plots, hybrids that are grouped as flex hybrids have more of a potential to flex backward when under stress of any source compared to the hybrids grouped as fixed ear type," Ferrie says.

flex hybrid n plotTo learn more about not leaving yield behind, Ferrie planted four genetics from AgriGold Hybrids, two of which were classified as flex hybrids and two as fixed hybrids. In 2010, the second year of this test plot, the field was in a corn after soybean rotation and the base application of nitrogen was 150 lb.

"We split the planter and planted each hybrid at 32,000, 34,000 and 36,000 plants per acre," Ferrie explains. "Then we sidedressed at three rates: 60 lb., 90 lb., 120 lb."

With one of the flex hybrids, there was a 60 bu. loss in the replications planted to 36,000 compared with the 32,000 plants per acre when only 60 lb. of nitrogen was sidedressed.

"As in our previous studies, the fixed hybrid has a more determinant ear type and tends to respond more as population increases," Ferrie says. "And those fixed hybrids have less of a tendency to go backward in yield when they are under stress."

Ferrie cautions that reaching the next yield goal is not as simple as pushing populations higher and higher. Make sure adequate nitrogen and water is also available. Turn to your seed salesperson for the most accurate information on the corn hybrids you plant and how to position them with your management practices.

In the Hot Zone

Nematodes are an emerging pest, and one that the Farm Journal Test Plots program has been studying for more than five years.

"The threat posed by these pests is increasing," Ferrie says. "With more no-till and reduced tillage as well as more acres in corn-on-corn, nematode pressures have increased."

The test plot crews in central Illinois, led by Ferrie, and in southern Michigan, led by Farm Journal Associate Field Agronomist Missy Bauer, have GPS mapped the hot spots for high nematode pressure.

nematode comp"We went out into the field and tested for nematodes," Bauer says. "With the soil samples, NDVI maps and yield maps, we could ground truth the hot spots of high nematode pressure. It’s important to know where your nematode pressure spots are, and nematodes can be hard to identify because the only way to diagnose the problem is by pulling soil samples and having them analyzed in the lab."

Bauer’s nematode testing included 366 samples across more than 7,000 acres, and 97.5% of samples had corn nematodes.

Ferrie and Bauer both put out test plots with today’s available nematode controls including Avicta Complete Corn from Syngenta and Votivo from Bayer treated on AgriGold Hybrid seed. Both agronomists ran split planter trials to observe the response across the fields and especially in the known high pressure zones.

nematode comp 2"With both of the treatments, we could see visual differences in the roots," Ferrie says. "We had more positive results in the poor soils with more nematode pressure rather than the heavier soils."

Bauer’s test locations in Michigan and Indiana included fields in the following production practices: corn on corn in conventional tillage, corn after soybeans in no-till and corn after soybeans in conventional tillage.

"We saw in our plots that in low to moderate pressure, there wasn’t a visual difference in plant growth or roots with the naked eye," Bauer says. "But in the hot spots, there was a big visual difference with the treatment. When we evaluated the first, second and third sets of crown roots we saw less root hairs, stubbed off roots and reduced rooting depth on the nontreated corn. However, it was not 100% control and we still observed some damage to the roots with both seed treatments."

Both Ferrie and Bauer report that there was some variability in yield data.

"With the visual differences we can tell we’re doing something," Ferrie says. "Nematode control is something we’ll continue to test."

Kick off with Starter

This year could be a big year for starter fertilizer as farmers look at production practices to gain bushels in the field.

"It’s all about timing and placement of the fertilizer," Ferrie says. "In our test plots, we’ve learned to expect a 7 bu. to 10 bu. response when applying starter fertilizer."

One additive to consider incorporating into your starter is zinc. "The key to zinc is to get a quality zinc source, and mix according to label," Ferrie says. "We had a 7 bu. response to adding 9% EDTA chelated zinc at the rate of 1 qt. per 20 lb. of phosphorus. Zinc helps bring consistency to our starter responses."

The 2010 season marked the third year that the test plot crews have looked at Avail from SFP as a starter additive. "Some of the years’ data was more positive than others, much like starter response varies year to year," Ferrie says. "One of the main problems with phosphorus availability is that it gets fixed with cations in the soil and is not available to the plant."

Avail is a polymer with a large negative charge that attracts the cations instead of them fixing to the phosphate.

"We looked at tissue tests and dry plant matter to understand how Avail affects the phosphorus in the plant," Bauer explains. "When we evaluate phosphorus uptake based on those samples, we have found that Avail does increase phosphorus in the plant."

The test plots included testing Avail in starter rates from as low as 3 gal. per acre to higher rates of 15 gal. per acre. Avail use rates are volume dependent, and Ferrie and Bauer both report that their strongest return on investment occurred in low rates of starter fertilizer.

"The yield increase from Avail was stronger at the lower rates of starter, and as starter rates increased, the response decreased. This indicated that at the higher rates phosphate availability was less of a limiting factor," Ferrie says.

"This makes products such as Avail well-suited for in-furrow applications with low rates."
In her northern Corn Belt geography and lighter soils, Bauer observed similar yield increases when Avail was applied in low starter rates in-furrow and high starter rates in 2"x2" placement. She cautions farmers should keep in mind the risks associated with starter fertilizer. With in-furrow starter, there is potential for seed burn. Factors that affect seed burn are soil type, soil moisture, starter quality, seed quality and furrow closure.

Starter can change plant maturity by as much as seven to 10 days, which most of the time will lead to higher yields and drier corn. Based on her test plot research, Bauer says additives, such as Avail, can also advance maturity.

"But in some cases, like the hot summer of 2010, you can push maturity forward so the plant pollinates in the hottest weeks of the year and penalizes yields," Bauer says. "That is a risk you take with starter, and maybe two out of 10 years will it set you backward."

Plant Placement

Soybean plant density plots were the first effort undertaken in the Farm Journal Test Plots program. Since then, the program has also studied corn row spacing to better understand how to take yields to the next level.

With more than two decades of data, Ken Ferrie has studied twin row, 10", 15", 20" and 30" soybean spacings.

"We’ve learned to be more careful about backing up populations in the wide rows (20" and 30")," he says. "Farmers should be more careful about increasing populations in the narrow rows."

twin row corn plotHe cites one test plot that shows the highest yield for twins at 120,000 plants per acre; for 20" rows at 160,000 plants per acre; and for 30" rows at 200,000 plants per acre.

"This is reverse as to what farmers think. Typically they’ve drilled beans at high populations, and when switching to a planter have lightened populations," Ferrie says. "Our best responses came from planting viable seed populations in narrow rows between 120,000 and 160,000 plants per acre. In our wider rows it’s not as clear, but that safe range is within 160,000 to 200,000 plants per acre."

Ferrie notes that the exception has occurred in years when planting is drastically delayed. In that case, he suggests to farmers that late planted beans need to be planted thicker across all row spacings.

While corn row spacing has been part of the test plot program for more than a decade, in 2010 the study was extended to include the lighter sandier soils in Michigan that Bauer works with.

"We planted our plots with five populations ranging from 28,000 to 42,000 plants per acre," Bauer says. "Across all of our plots, twin rows averaged 9.5 bu. more than the 30" rows at the same planted populations. This was based on three site locations, which were each replicated three times."

In central Illinois, Ferrie reports that his research showed a 7 bu. to 10 bu. response to twin rows and 20" rows spanning multiple years of plots.

"Our data from 2010 looks a lot like the past 10 years of data," he says. "In one field, the average yield for twins was 7 bu. more than 30" corn, and even higher in the tougher parts of the field."

Ferrie and Bauer both report that twin row corn yields topped off about 3,000 plants per acre more than when 30" row corn plateaued.

If considering a change to narrow corn rows, Ferrie recommends farmers look at the 3% to 5% yield increase at the same planting populations and put it to pencil.

"There are two scenarios in which I suggest growers consider narrow rows," Ferrie says. "In lighter soils, you want the leaf canopy to close quicker to conserve water. In that situation I would recommend narrow rows with lower populations.

"The second situation that is suited for narrow row corn is when plant populations need to be higher to take full advantage of soils with high fertility and high soil water-holding capacity," Ferrie says.

Ferrie also suggests that when moving to narrow corn rows, give serious thought to variable-rate planting. This would allow you to decrease population on poor ground and increase population on heavier ground. He reminds farmers that narrow rows and higher populations require diligent scouting to stay on top of disease pressure.

Thank You to Our Test Plot Partners

Each Farm Journal Test Plot is a cooperative effort. Thanks go to: AgriGold Hybrids, Mike Kavanaugh and Amy Bousley; Syngenta, Palle Pedersen and Cliff Watrin; Bayer Crop Science, Jennifer Riggs, Tristan Mueller and Ben Potter; Yetter Manufacturing, Pat Whalen, Susan Wherley and Scott Kale; Great Plains Manufacturing, Tom Evans, Doug Jennings and John Sites; Kinze Manufacturing, Susanne Veatch, Laura Blomme and Mike Feldman; AGCO, Alexis Max and Reid Hamre; Farm Depot and Mark Laethem; Versatile and Adam Reid; McCormick USA, Doug Rehor and Kurt Schenck; Unverferth Manufacturing and Jerry Ecklund; Orthman Manufacturing, Adam Souder and John Bell; Jensen Electronics and Stephen Jensen; Case IH, Tony McClelland, Tom Dean and Travis Maier; AutoFarm; Trimble and Sid Siefkin; OmniStar and John Pointon; SFP, Larry Sanders, Jeff Pewitt, Tony Donoho and Melanie Acklin; Bob Kuntz; Don Schlessinger; Doug and Craig Van Hoveln; Bob and Mary Kochendorfer; North Concord Farms; Stamp Farms; Willibey Brothers; Heffelfinger Farms; Crop-Tech Consulting, Brad Beutke and Isaac Ferrie; B&M Crop Consulting, Bill Bauer, Vicki Williams and Terry Finnegan.

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