Dairy industry helps offset high fertilizer costs with manure in Wisconsin

Samantha Hendrickson
Wisconsin State Farmer
About a third of the nitrogen for corn grown in Wisconsin comes from dairy manure, says UW expert.

Fertilizer price increases hit farmers hard this year, but thanks to manure, Wisconsin crop farmers weren't hit as hard as others. 

According to the University of Wisconsin Madison-Extension, farmers that were able to access manure from dairy farmers were able to offset costs by the use of the natural fertilizer. 

Reported prices for all major types of nitrogen, phosphate, and potash fertilizers increased more than 5% during September, and have continued to increase through December, though they now appear to be stabilizing. 

While other states brag big dairy and crop industries, Wisconsin's insulation from fertilizer price spikes is thanks to having more cows per acre than corn per acre, according to Paul Mitchell, a professor in the UW-Madison department for Agriculture and Applied Economics.

"About a third of our nitrogen for corn comes from dairy manure," Mitchell said. "And we have more cows per acre of cropland." 

However, manure isn't easily accessible. It's difficult to transport due to its high water content and therefore large volume, so it can't usually go beyond it's own farmland or crop farms neighboring dairy farms.

But it's lack of transport ability shouldn't dissuade you from seeking it out, according to Matt Ruark, a professor of soil science at UW-Madison and soil nutrient expert. 

"We think of [manure] as a waste stream, but it is has relatively high nutrient value in terms of nitrogen, phosphorus and potassium. Those are big three nutrient inputs into our corn production systems," Ruark said. 

Other grains, besides corn, that are harvested above ground can also benefit from manure during these price increases. However, potatoes, cranberries and other vegetable farms with underground harvesting cannot use manure due to food safety laws.

"Especially vegetable crops that are for direct human consumption, they can't have that direct manure application because of the pathogens like e-coli that may come with the manure," Ruark said. 

While getting the manure can be tricky, if it fits for your farm and soil, it's worth trying, Mitchell said.

 "All farmers will find it valuable to look for ways to use manure and fertilizer more efficiently by using soil and manure testing and following university and science-based guidelines," Mitchell said. 

Samantha Hendrickson can be reached at 414-223-5383 or shendrickson@jrn.com. Follow her on Twitter at @samanthajhendr.