At TerraMax in Bloomington, Minn., the company is developing and selling microbiological products which leverage naturally occurring microbes in soil. Based on scientific research, soil microbes, that include fungi, bacteria and viruses, can actually be beneficial to soil and increase yields in crops ranging from corn to soybeans to wheat.

Biological products is an expanding field in agriculture, said Tom Proepper, TerraMax chief operating officer.

“People are asking questions. It takes an open mind. This just seems to be one of the new dimensions of modern crop production,” he said.

TerraMax flagship products are a bradyrhizobium-based innoculant for soybeans and an azospirillum innoculant for corn. In field trials of corn over the last three years, powdered treatments of azospirillum have helped boost yields by more than four bushels per acre over untreated checks.

“We have a relatively short portfolio right now. We have some traditional rhizobia products and we have an azospirillum product that functions as a nitrogen fixing bacteria,” said Proepper.

He indicated that TerraMax Research and Development has other microbials in the works.  These new offerings would be nutritional for plants directly and also used to improve soil health in general.

Proepper cited recent University of Wisconsin turf grass testing — called N15 testing — that indicated 25.8 percent of the nitrogen in the tissue of the turf grass stemmed from the TerraMax bacteria treatment.

“Granted that’s just a one-time event but it’s a data point that we’re pleased to be working from,” he said.

Once inoculated, soils aren’t enriched forever.  Microbiological additives in a corn environment are an every year application, Proepper said. In a corn-soybean rotation, that suggests usage would be every other year just with the corn. In a continuous corn strategy, there’s no residual benefits by increasing the application rate.

“A higher rate doesn’t increase the microbiological activity, we’re finding out,” said Proepper.

The additives can be used as a seed treatment, or as a tank mix with pop-up fertilizer. He notes they get better results, better yield bumps when used as a dry seed treatment. With soybeans, seed treatment is the popular choice. The TerraMax product can be mixed with other fungicides and insecticides being applied. For corn applications, blending with a liquid pop-up fertilizer for in furrow application is the popular choice.

Costs for the TerraMax products average $5 to $7 per acre depending upon choice of a liquid or a dry product and seeding rate.

“We’re seeing good pickup on our products in the western Corn Belt,” Proepper said, “and also steady expansion here in the upper Midwest where we have great, healthy soils. I see it going to Missouri. California has started planting more corn and we’re seeing movement out there now too.”

Soil temperature does play a factor in microbe activity.

“Corn temperatures don’t harm our microbes; they’re just not as active as compared with optimum planting temperatures of 65 degrees and above,” he said.

TerraMax does not have statistics on the effectiveness of later applications on crops.

“Farmers tend to be very imaginative with what they do,” said Proepper. “I wouldn’t be surprised if some might be doing just that. In many cases those cropland soils need some special attention and rebuilding.”

By using a unique stabilizing process and media, TerraMax has extended the  shelf-life of its azospirillum product stored in packages from 18 to 24 months.

Other major companies in the market are Valent Biosciences, Marrone Bio Innovations, Loveland Products, and Becker Underworld.

Tom Proepper was interviewed at the Minnesota Organic Farming Conference in St. Cloud in January.

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The Land Staff Writer​