DARLINGTON, Wis. — The Lafayette Ag Stewardship Alliance’s recent annual meeting figuratively covered a lot of ground, with a program focused on land- and water-conservation issues.

The farmer-led watershed protection group — with its 23 farmer-members — also literally covers a lot of ground. Together the farmers have implemented conservation practices on 38,444 acres of land. Implementing conservation practices is a requirement to be a member of the group, according to Jim Winn, a dairy farmer and president of the Lafayette Ag Stewardship Alliance.

The group also has worked with the Wisconsin Chapter of The Nature Conservancy to collect and document data on conservation practices that members already have implemented. Members have implemented one or more of 14 such practices. Some of the practices are no-till, conservation tillage, split-fertilizer application, low-disturbance manure injection, cover crops, grassed waterways and nutrient-management plans.

Paige Frautschy, agriculture-strategy manager for The Nature Conservancy, used data from the U.S. Department of Agriculture’s Conservation Effects Assessment Project as well as data from nutrient-reduction strategies in the upper Midwest to estimate how the practices help reduce nutrient loads.

“These are just estimates so we can have a better idea of what percentage each conservation practice has on nutrient loading,” she said.

The Nature Conservancy will continue to collect farmer data annually to help determine further reductions in nutrient loading. Frautschy said in the future she may be able to use SnapPlus for more site-specific evaluation. SnapPlus is software for developing nutrient-management plans in accordance with the Wisconsin Natural Resources Conservation Service’s “590 standard.” The software also can generate erosion estimates for each field and the Wisconsin Phosphorus Index, according to the Conservation Professional Training Program.

The Lafayette Ag Stewardship Alliance meeting featured a presentation by Ken Bradbury, director of the Wisconsin Geological and Natural History Survey, University of Wisconsin-Extension. Bradbury shared initial results from the Southwest Wisconsin Groundwater and Geology Project, which began in fall 2018.

The two-year study is funded by the Lafayette Ag Stewardship Alliance as well as Lafayette, Grant and Iowa counties. The farmer group provided $7,000 in funding for the project.

“The group is committed to working with a variety of partners to make sure we have clean surface waters and clean groundwater,” Frautschy said.

Bradbury discussed the hydrogeology of southwestern Wisconsin. The area features bedrock aquifers and carbonate rock near the ground surface. Groundwater can move quickly through fractures and karst conduits in the rock. Both geology and soil depth affect groundwater vulnerability, he said. Bradbury and his project colleagues have been developing geological maps to depict depth to bedrock; the data will be included in an analysis of well-contamination factors.

Well construction in the area is important because wells with shallow casings — cased above the water table — are more vulnerable to contaminants originating at the land surface than more deeply cased wells, Bradbury said. Water samples from randomly selected private wells were collected in November 2018, and analyzed for total coliform E. coli and nitrates at UW-Stevens Point.

Joel Stokdyk, biologist at the U.S. Geological Survey, reported the results of the first of two sampling events. Water-quality issues in the tri-county area generally exceed statewide averages for the contaminants.

Of the wells tested, 42 percent had bacteria or elevated nitrate levels, but the sources aren’t well-known. The scientists plan to collect another round of random samples in April. They also will sample a subset of wells for host-specific micro-organisms unique to humans, cows and pigs. They will do more focused testing for microbial sources on sub-sample sets later this year, Bradbury said. From that they hope to identify the relative sources of contamination. At the end of the project — a little more than a year from now — they will provide a report and hold public meetings.

Lynn Grooms writes about the diversity of agriculture, including the industry’s newest ideas, research and technologies as a staff reporter for Agri-View based in Wisconsin. Email lgrooms@madison.com to contact her.