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Serving: IN
combine harvesting mature soybeans
TIME TO TEST: Jim Zimmerman tested soybean seeding rates in replicated test plots over the past four years, aided by Larry Temple, former Extension educator in Jay County, Ind.

What should you test on your farm?

Conducting field trials with your soils and conditions can turn up valuable information.

Is on-farm testing more trouble than it’s worth, especially if you replicate treatments? Jim Zimmerman doesn’t think so.

In fact, Zimmerman, Redkey, Ind., is convinced time spent over the past four years running seeding rate trials on soybeans was well worth it. As a result, he’s spending less on seed today than before, because he’s learned he can plant fewer seeds per acre and still harvest good yields.

“Larry Temple was looking for someone to cooperate on a seeding rate trial, and I was interested,” he recalls. “We did passes of different seeding rates and repeated them across the field. I relied on Larry to lay out the design and then evaluate the results. We’ve been able to cut back on seeding rate and not hurt yields.”

Temple was the Jay County Extension educator. Although he retired in September 2019, he helped Zimmerman harvest his plots and analyzed results

Michael Langemeier, a Purdue University Extension agricultural economist, says that potentially trimming soybean seeding rates could be one way to reduce input costs without impacting yield. He strongly advises against making any cuts that could threaten yield potential. If you’ve got valid test results from your own farm or a site close by, that gives you even more confidence.

Field-scale trials

In Shelby County, Ind., near Morristown, Ken Simpson has cooperated with Purdue University Extension agronomists Bob Nielsen and Jim Camberato, plus other Purdue researchers, over the past several years. Scott Gabbard, Shelby County Extension educator, also works with Simpson.

Simpson became interested in field-scale trials on his farm when he was trying to determine if planned, late-season nitrogen applications would boost net returns. Results proved to be inconsistent. For the past two years, he’s cooperated on sulfur trials in corn.

“We’re seeing some exciting results and real payback on my fields,” Simpson says. Camberato notes that they don’t see a response to sulfur everywhere. It’s another reason why on-farm testing on your own farm can be critical.

“Working with these guys has been a pleasure, because I’ve learned so much,” Simpson says. He adds that with GPS, autosteer, and planter and yield monitors, planting and harvesting field-scale trials with replicated strips doesn’t take as much time as you might think.

Camberato notes they’re always looking for more people to cooperate in field-scale studies. Email him at

Other examples

Roger Wenning and his son, Nick, Greensburg, Ind., are involved in a different kind of study beginning this year. Known for using cover crops, sharing knowledge at field days and developing healthy soils, the Wennings are cooperating with soil conservation specialists who want to follow their progress on a new farm they’re tackling this year.

“There’s not much soil microbe activity there now, and they want to see how long it takes to improve soil health using practices we’ve used elsewhere,” Nick says. “They seeded cover crops last fall, but they realize it will take time to build up soil activity.”

Stephanie McLain of the Natural Resources Conservation Service state office and Joe Rorick of the Conservation Technology Information Center visited the site and took various soil samples and measurements to establish a base line. They’ll return periodically to reevaluate the soil.  

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