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Corn+Soybean Digest

Eye On Energy Highlights

This year's Conservation Tillage Conference & Expo's theme, Eye on Energy, looked at trends in conservation practices and explored ways for farmers to better manage spiraling energy costs.

Here's a wrap-up of several of the presentations, plus special advice on how to manage a rotation of more corn on corn. Sponsored by The Corn And Soybean Digest, you can find complete presentations at: or at Thanks to Case IH for being a major sponsor and to all the exhibitors at the trade show.


Typically, farmers hear they should expect a 10% yield reduction when going corn on corn. That's not always true these days, according to Tony Vyn, Extension agronomist at Purdue University.

“Now we know it depends first on the soils, second on the tillage system (the loss can range from 4% to 18%) and thirdly on use of new hybrids, especially with our more stress-tolerant hybrids,” he says. “Still, even with better hybrids, you won't match the yields you'd get with a regular corn-soybean rotation.”

Yield reductions for corn after corn also vary with growing season precipitation, length of rotation (sometimes second-year corn is better than continuous corn) and whether fields have recently had forage crops or manure.

Vyn says with higher residue from corn on corn in a conservation tillage program, it's important to keep plants growing evenly, and not have taller and shorter plants next to each other in the same row. If you can do that, he says, yields should equal what you'd get with conventional tillage.

Also, he says starter fertilizer is more important for corn after corn with conservation tillage. “You'll need more nitrogen (N) for any version of corn after corn than a typical corn-soybean rotation,” he adds.


Anytime you change tillage practices you're altering the field ecosystem, says Keith Jarvi, integrated pest management specialist at the University of Nebraska, Northeast Research and Extension Center in Norfolk.

With reduced tillage expect an increase in early season insects such as wireworms and white grubs because of earlier planting dates, more residue and a succession of cool, wet springs. “These factors may slow germination and keep wireworms in the zone longer,” Jarvi says.

For continuous dryland corn, he says control methods for corn rootworm are more influenced by environmental conditions and you'll need to identify fields with low beetle numbers. “Transgenics may have a slight advantage over insecticides here because of in-plant protection, which is less influenced by the environment,” he explains.

Overall, Jarvi says crop rotation is still the most effective way to reduce rootworm densities. “Insecticides for larval control reduce injury to roots, but do not provide a high level of larval mortality; and larvae may feed on roots outside the treated zone,” he adds.

For other insects, he urges farmers to scout and use economic thresholds, then treat only when necessary.


When it comes to fertilizer for corn on corn and reduced tillage, plan on more split applications of N, says George Rehm, retired nutrient management specialist at the University of Minnesota. However, he adds that N rates do not change with different tillage systems.

“Placement is the important consideration,” Rehm says. “For example, if N comes in contact with residue, you're not effectively using it. Nitrogen absorbed by crop residue leads to inefficient use.”

With rates, plan on using about 40 lbs. more of N when you go corn on corn, he advises. Also, band an application in the fall and then combine a subsurface band with seed-placed fertilizer. “Subsurface banding is one of the keys to success with conservation tillage,” Rehm says.

In the western Corn Belt, he recommends a soil test for residual nitrate-nitrogen with N rates adjusted for the measured residual nitrogen.


Auto guidance is growing across the U.S., especially with ag retailers. In 2006, about 20% of ag retailers used GPS auto guidance for custom application, says Jess Lowenberg-DeBoer from the Site Specific Management Center at Purdue University. In the Midwest, almost 80% of custom applicators use GPS lightbars.

“There's been a similar rapid adoption by farmers, especially larger acreage grain farmers,” he adds.

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Here's how Lowenberg-DeBoer sums up common assisted steering systems:

  • Assisted steering — starts at less than $5,000 and has a 15-30 cm accuracy with WAAS correction.

  • Differential GPS (DGPS) — starts at about $10,000 and has a 10-15 cm accuracy.

  • Real Time Kinematic (RTK) — runs $30,000-60,000 and has a 2 cm accuracy.

Lowenberg-DeBoer says that with auto-guidance you can:

  • Cover more ground with the same equipment.

  • Operate more easily under poor visibility conditions, such as at night, in fog or dust.

  • Run at higher field speeds.

  • Reduce skip and overlap.

  • Use mismatched equipment widths (8, 12, 16 and 24-row).

  • Rip-skip or racetrack to reduce turning time. (Skipping every other pass and coming back to fill in.)

Besides those benefits, he points to labor advantages such as increased flexibility in hiring. “The quality of work is less dependent on operator skill and you can use unskilled labor with a lower wage rate. Plus, the new generation is more familiar with the technology,” he says. “There's less fatigue, too, so you can work longer hours.”

The downside, he points out, is that you may lose some current employees who are not comfortable with computer technology.

There are field efficiency benefits, too. For example:

  • Auto-guidance allows acreage expansion with the same equipment.

  • Auto-guidance is an alternative to hiring more labor.

  • Systems having operations with overlap gain more.

  • Guidance can reduce energy use by reducing skip and overlap; and with controlled traffic you're operating equipment on firm soil.


Stacked traits are becoming more popular so it's important to match which stacked traits you use to your management system, says Paul Bruns, crop consultant with Precision Consulting Services, Canby, MN.

In 2006, he estimates that 32% of hybrids had corn rootworm control, 62% had Roundup Ready technology, 62% had European corn borer control and 19% were triple stacks.

To help you find the right genetics, Bruns says to:

  • Look deep into the agronomics of the hybrid.

  • Find genetics that can handle your environment.

  • Be careful of large plot data.

  • Look beyond the details of the seed catalogs.

  • Ask your dealers for more information.

In addition, Bruns says to look at local plot data to help you analyze what to plant. For example, he suggests looking at other producers' strip trials and compare them to yours. Are they in similar soils, fertility programs, tillage programs and have similar locations? Then check county plots, university trials, F.I.R.S.T. plots and your own farm using yield monitor data.


U.S. corn farmers will likely need more N fertilizer this spring than in a typical year, says Bruce Vernon, director of crop nutrients marketing and risk management services for Agriliance, a crop inputs supplier in Inver Grove Heights, MN.

He predicts N fertilizer supplies this spring could be limited within specific markets, and N markets will likely stay volatile for 8-9 years.

“Farmers who don't order now might be unable to obtain their first choice for an N product later,” cautions Vernon. “Farmers should talk with dealers soon.”

The U.S. fertilizer supply chain takes a lot more planning than it did when most of the fertilizers were produced in this country, and when energy prices were less volatile, explains Vernon.

“Some fertilizer dealers experienced a tough year last year because they brought in more product than they sold,” he says. “Those dealers are going to be cautious about ordering too much product again in this year.”

Sticker shock, particularly with urea, may be a common occurrence for farmers who haven't been keeping track of fertilizer prices, Vernon says. He points out that it takes about 45 days to get urea to the U.S. Also, the cost is preventing suppliers from having an overstock because there's too much risk.

“Urea is the easiest N product to handle and transport, but it has increased rapidly in demand all around the world to almost $100/ton since October,” he says.

Currently, the best value for an N fertilizer is anhydrous ammonia, points out Vernon. “However, the anhydrous ammonia distribution system has been close to capacity for several years,” he cautions. “Its supply might be limited in certain areas if a lot of farmers decide to switch to it who would normally apply another form of N, like urea or urea ammonium nitrate (UAN).”

So far, prices for P & K have been fairly stable, he says. However, those prices could increase significantly if Chinese buyers enter that market this winter or spring.

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