Soil health: Where are we with the science?

Gloria Hafemeister

Wisconsin Dells — Soil health is all the rage, but what do soil scientists know about it?

Dr. Matt Ruark, soil scientist with the University of Wisconsin-Madison, attempted to answer that question during the Discovery Farms annual conference in Wisconsin Dells.

Speaking to an audience of more than 200 crop consultants and farmers, Ruark talked about current research projects that look at the basics of soil science and also invited producers to be a part of the effort to understand soil.

Matt Ruark

“You need to get into soil health as a concept and a monitoring tool," he said, "but be careful not to jump into it so far as a diagnostic tool for making decisions.”

Pointing to Discovery Farms method of looking at all types of soil types, topography and weather conditions, Ruark said each farm will be different and each farm has a different set of challenges and advantages.

Discovery Farms also considers all types of farming systems, including conventional (big and small), organic and grazing.  It also looks at farms raising all types of crops and livestock.

The program does nonfarm research all around the state. It monitors water, soil, phosphorus and nitrogen coming off of fields; assesses nitrogen use efficiency and soil health; and works to understand the relationship between land management and water quality.

Discovery Farms is farmer led when it comes to establishing research priorities.

Ruark pointed out there are two ways to evaluate the benefits of some of the research. Farmers need to consider whether best management practices, determined through the research, will help to increase yields or help reduce the need for additional fertilizer.

Farmers use a variety of systems, and each system has an influence on soil health.

Cover crops are helpful in holding nutrients in the soil.

Reduced tillage decreases disturbance of the soil, thereby improving its ability to retain nutrients and store carbon dioxide from the atmosphere. Cover cropping between cash crop seasons maximizes the time each year that living roots are building soil nutrients and keeping the soil covered as nature designed. Diverse crop rotations build nutrients, limit erosion and foster carbon sequestration.

The environmental impacts of systems also vary. Controlling erosion is important, not only for productivity on the farm but also to protect waters that are being degraded by water run-off containing nutrients. At the same time, here as everywhere, farmers are dealing with more extreme weather events — causing more severe and unpredictable floods and droughts.

By focusing on improving soil health, it is possible to boost productivity and reduce those environmental impacts.

Tests like this are an indication of the differences in soil health.

Wisconsin has numerous types of soils, each requiring a specific set of actions to ensure optimum soil health.

Ruark invited producers to be a part of the state-wide evaluation of farming systems.

The Nitrogen Use Efficiency Study is working to build a database that will help guide farmers in making decisions related to building soil health, preserving nutrients and protecting the environment.

In 2015, 22 farmers in St. Croix, Monroe, Vernon, Dane, Dodge, Jefferson and Rock Counties participated in the study, and the number grew in 2016. Eight farms are hosting monitoring sites, which include six in Monroe and Vernon Counties, three in St. Crox County and one in Rock County.