Addressing change and challenge in manure applications

Gloria Hafemeister
Correspondent
The recent two Discovery Farms virtual conferences highlighted changes regarding manure and nitrogen applications in fall and winter in many areas of Wisconsin and Minnesota.

MADISON – 2020 certainly brought a lot of change and challenge for agriculture producers. While the pandemic forced Discovery Farms Programs in Wisconsin and Minnesota to cancel the annual conference, farmers, soil conservationists and crop consultants were still able to take advantage of educational opportunities online.

The theme for this year's Discovery Farms’ weekly virtual conference series is “Keeping up with your conservation goals through change and challenge.”

A recent conference featured Dr. Christine Morgan of the Soil Health Institute in North Carolina who described soil health as the capacity of soil to function as a vital living ecosystem sustaining plants and animals. She notes that there are very different soils in different parts of the country or even within a state. However, that doesn’t mean they can’t all be healthy and productive.

As part of her work at the institute, she and colleagues have examined 124 samples across the country demonstrating different soil and practices. 

“To measure this we look at how each part of soil health was affected by various management systems: rotation diversity, crop count, organic amendments (manure), cover crops, decreased tillage; and residue retention,” she said.

“No matter what research method was used to test soil stability the results were positive- when putting it all together, location will make a big difference on which factor makes the biggest difference in soil health,” Morgan added.

Kristin Brennan, Minnesota Natural Resources Conservation Service (NRCS) assistant state soil scientist and soil health specialist focused on various practices applied on 2.4 million acres in Minnesota. 

“When these practices were put in place, farmers reported better structure and water infiltration, and better soil,” she said.

State Rule Changes

During last week’s conference several speakers looked at how different types of soils with different management practices can handle the application of nitrogen and manure.

Speakers addressed the topic of the groundwater protection rule and how it affects farming and nitrogen management. It is a timely topic since the Wisconsin Department of Natural Resources (DNR) is currently in the midst of introducing changes to the current NR 151 rule

According to the DNR, the NR 151 rule modification is to develop a targeted performance standard to abate nitrate pollution in areas of the state with highly permeable soils which are susceptible to groundwater contamination (sensitive areas) for the purpose of achieving compliance with the nitrate groundwater standards.

Chris Clayton, chief ag runoff specialist with the Bureau of Water Management, updated the 200 participants in this week’s Discovery Farm session about the proposed rule revisions. These revisions define sensitive areas in the state and the performance standards needed to protect groundwater quality in these areas.

Clayton and others with the DNR have been working together with key public and agriculture industry stakeholders, state agencies, the State Legislature, the governor and the general public to update NR 151. 

Public participation is a critical component of agency rulemaking, Clayton says. In December 2019, the DNR board approved the scope of the rule and authorization with the purpose of revising the rule. 

During the months that followed, officials worked to define where the rule will apply, the soils that are highly susceptible to groundwater contamination from nitrates.

“We will focus on areas with groundwater data showing nitrate contamination,” he said. "The goal is to achieve groundwater standards for nitrates of 10mg/L by limiting nitrate leaching from applications of nitrogen fertilizer or manure to the groundwater.”

Clayton added, "Our authority is to put together a numeric performance standard and implement that standard.”

The revised standards take a long look at prohibiting commercial nitrogen applications and manure applications in fall and winter.  Clayton says included in that goal is to provide some flexibility for farmers to meet those standards including crop rotations, cover crops and other strategies. Those involved in writing the rule specifically looked at exceptions to the rules that include establishing fall seeded crops or maintaining established fall crops. 

Minnesota's efforts

Minnesota has been conducting similar studies and is just a little ahead of Wisconsin in its attempts to write rules regarding nitrate contamination.

Larry Gunderson of the Minnesota Department of Agriculture shared information about his state’s groundwater protection rule. Minnesota's Groundwater Protection Rule went into effect in June, 2019. It minimizes potential sources of nitrate pollution to the state’s groundwater and protects the drinking water.

The rule restricts fall application of nitrogen fertilizer in areas vulnerable to contamination, and outlines steps to reduce the severity of the problem in areas where nitrate levels in public water supply wells is already elevated.

The rule contains two parts with each part containing separate criteria and requirements. Depending on where producers farm, they may be subject to one part of the rule, both parts, or none at all.

Greg Klinger, Extension Educator - Agricultural Water Quality Protection at the University of Minnesota, shared what he has learned through his research on how different nutrient management practices, weather, soils, and geology can impact the amount of nitrates that leave agricultural fields and end up in streams or underground aquifers.

Defining vulnerable

Klinger looked specifically at the application of nitrogen fertilizers in the fall and on frozen soils in these vulnerable areas. While there is a specific technical definition for “vulnerable”, in general terms, one of three factors must be present for groundwater to be more susceptible to contamination from activities on the land surface: sandy or gravelly (otherwise known as coarse-textured) soil, karst geology, or shallow bedrock.

Looking at best management practices he notes that there are black areas, white areas and a lot of grey areas. There are also tradeoffs between simplicity, usability and accuracy.

Klinger points out that management practices that do not cause contamination issues in one groundwater area may still cause contamination in another due to the unique soils and geology. For example, just because groundwater in one area may have higher nitrates levels does not mean producers working in that area are doing a “worse” job of managing nitrogen than those elsewhere. "They could just be dealing with a more challenging geology," he explained.

Discovery Farms Wisconsin

Numerous opportunities

With Discovery Farm programs providing on-farm research in both states there are numerous opportunities for farmers and researchers to learn from one another.

The Discovery Farm virtual conference will continue with a session on tile drainage in both states and what edge-of-field monitoring has revealed. The January 20 session will zero in on rules and tools for manure management followed by a January 27 session on applying skills learned to manure management.         

To register for the free upcoming on-line conferences contact Discovery Farms website at https://bit.ly/3pTDM30