Bruce Klein is selecting his corn hybrids, soybean varieties, herbicides and insecticides more and more on cold, hard performance facts. So are John Jeschke and many other farmers.

These growers are participating in Pioneer's split-planter comparison program.

"We have evaluated dozens of split-planter data sets from this past harvest," reports Tom Doerge, precision farming agronomist for the company.

"The majority have been comparisons of two corn hybrids or soybean varieties," Doerge says. "However, we also have looked at special cases such as the effect of high-pH soil on a chlorosis-resistant hybrid vs. a chlorosis-susceptible hybrid. In another situation, it was a phytophthora root rot-resistant soybean variety compared to a susceptible variety."

Other comparisons, points out Doerge, have been one soil insecticide vs. another, and Bt vs. non-Bt hybrids in a year with low corn borer pressure.

"This year, a split-planter test will compare corn yields obtained in repeating strips of fall- and spring-applied anhydrous ammonia. It will be in a field with both hills and low, wet spots. This will help answer questions about nitrogen loss resulting from spring vs. fall application."

Bruce Klein, who farms with his father Ben, cousin Don Vance and Vance's son Dean near Lexington, IL, has been doing split-planter comparisons for several years. They have a planter that handles sixteen 30" rows for corn and thirty-two 15" rows for soybeans. They have had a yield monitor and yield-mapping capability since 1995.

"We've done a lot of comparisons of two hybrids," Klein says. "In 1998 we had nine separate trials."

They generally have 40-acre trials, with 20 acres for each hybrid.

"It doesn't take any longer to load the planter for the comparisons than to do normal loading," says Klein.

It does, however, take time to lay out the plots over winter, he points out.

In 1998, Klein and his partners also did three split-planter soybean yield comparisons. "It's more difficult to match planter size to combine size on soybeans," he says.

They also compared Force corn insecticide with Counter and Aztec.

"Going back to 1997, we compared Roundup Ready soybeans, using the Roundup program, vs. a competitive program."

At Rock City, IL, John Jeschke compared the same two corn hybrids in a 33-acre field in 1996 and again in 1998.

"The results have been interesting," he states.

"In 1996 there were places in the field where hybrid A outyielded hybrid B by 10 bu/acre due to soil type or soil conditions. There also were places where hybrid B outyielded hybrid A by 10 bu/acre. Yet, overall, there was less than a 1-bu difference in yield. Hybrid A was two points dryer, however."

In 1998, despite fairly similar growing conditions to 1996, the performances of the two hybrids were radically different. Hybrid A consistently outyielded hybrid B by 10-15 bu/acre, Jeschke says.

"The main lesson from this is that you may not get a true picture if you run only one side-by-side comparison of two hybrids."

Jeschke plans to continue using split-planter comparisons to check out proven hybrids against new numbers.

"I want to see how certain hybrids perform under certain field conditions and then plant each hybrid where it appears to be best-suited," he notes.

Bruce Klein wants to see how his on-farm research correlates with the aggregate studies being done by agribusinesses on various products.

"The companies do research over a wide geographic area," he points out. "If our findings correlate with their wide pool of research, I can better accept the research they do on products or practices where we don't do our own comparisons. I'll have more confidence in applying their research to our farm."

Pioneer's Doerge says the split-planter techniques will continue to be an excellent tool for yield monitor users to make comparisons. However, he emphasizes that, in many cases, the observed differences are dependent on the growing season. They may not be repeatable from year to year in the same fields.

"It's much safer to draw conclusions from comparisons that span multiple years or multiple locations, rather than on just one site-year," he says.