Farm Horizons, April 2012
Study of the impact of ag practices on water taking place at Groos farm
By Jennifer Kotila
When Joe Jacobs of Wright Soil and Water Conservation District brought the Discovery Farms Minnesota program to Sean Groos’ attention, the Howard Lake dairy farmer thought, “Sure, why not.” Participating in the study would show that farmers are willing to do their part in protecting Minnesota’s waters, Groos said.
Jacobs had initially spoken to Dr. George Rehm, Discovery Farms Coordinator, two years ago about building a water sampling and collection structure at a farm in Wright County, due to all the lakes in the area, Rehm said.
The Discovery Farms program is designed to collect accurate measurements of sediment, nitrogen, and phosphorus movement over the soil surface, and through subsurface drainage tiles. This will allow researchers to generate a better understanding of the relationship between agricultural land management and water quality.
After meeting with Jacobs and Rehm last fall, Groos agreed to allow a water sampling and collection structure to be built on the edge of one of his 45-acre fields. Groos is a dairy farmer who milks about 180-head of Holsteins. He plants corn and alfalfa in his fields, using manure as fertilizer. Information will be gathered to assess the water quality impact of Groos’ farming practices on the landscape and watershed surrounding the farm.
Groos tries to keep good farmer practices, such as leaving crop residue and ridges in the field to prevent soil runoff and erosion, he said. He also manages the application of manure, only applying manure to some areas in the fall, and incorporating it into the soil before it freezes. This helps to prevent the runoff of nutrients during the spring thaw and rains.
Although other farms in Wright County were suggested for the study, the Groos farm was picked for two reasons, Rehm said. First, Groos was interested in nutrient movement across his land, because he applies manure as fertilizer. Second, lakes Ann and Emma, which have been placed on Minnesota’s Impaired Waters list, are across the road from the field.
A total maximum daily load (TMDL) study has been completed on the lakes, and the study being conducted at the Groos farm will allow researchers to compare the computer modeling used by the TMDL, to the real-world samples taken from the Groos field. This will allow researchers to see if the computer models have been calibrated properly, Jacobs said.
Funding through the Clean Water, Land, and Legacy Act paid for the $30,000 structure, and will fund the lab analysis of the water collected at the Groos farm, according to Rehm.
The high-tech, solar-powered water sampling and collection structure at the Groos farm is positioned on the low side of the field, so that runoff water naturally flows through a device called a flume. The structure has two systems, one to collect data from surface runoff, and the other to collect data from the subsurface drainage tiles. The structure is continuously collecting rainfall, air temperature, soil temperature, soil moisture, and humidity data, along with water samples when runoff is present.
Although the structure at the Groos farm has been in place since late last year, the only measurable runoff that had been collected at press time was from the rain March 19-20. Results of lab tests for the samples collected were not yet available.
The structure at the Groos farm will be in place for five-to-seven years, monitoring the surface and subsurface drainage from the field.
TMDL study findings for lakes Ann and Emma
The goal of the TMDL study is to quantify the needed reductions in pollutants (sediments, phosphorus, and nitrogen) in order for lakes Ann and Emma to meet state water quality standards for nutrients. The TMDL study was completed using computer modeling to establish the cause of excess nutrients within the lakes. The computer model estimates that about 40 percent of the nutrient load is coming from within the lakes, and 60 percent is coming from water runoff within the watershed, Jacobs said.
In order to reduce the excess nutrients in the lakes, and bring them within state standards, the TMDL study calls for a nutrient reduction of 81 percent for Lake Ann, and 60 percent for Lake Emma. Because a large proportion of land in the watershed is agricultural and has manure applied to it, nutrient management in the watershed will need to focus on manure management, according to the TMDL study. However, internal nutrient loading (nutrients being introduced by fish, like carp, and weeds, like curly-leaf pondweed) is also a significant source of phosphorus and will need to be addressed through internal load controls.
The TMDL study has gone through the public comment process, and been approved by the Minnesota Pollution Control Agency, according to Jacobs. Following approval by the US Environmental Protection Agency, an implementation plan will be established to reduce the nutrients in lakes Ann and Emma, and bring them within state standards for nutrient loads.
The Discovery Farms Minnesota program
Discovery Farms Minnesota was launched in the fall of 2009, with a mission of gathering water quality information under real-world conditions, and providing practical, credible, site-specific information, which enables better farm management.
Support and assistance for Discovery Farms comes from the 15 farm organizations which comprise the Minnesota Agricultural Water Resources Coalition (MAWRC), the Minnesota Department of Agriculture (MDA), and University of Minnesota Extension.
The MAWRC organized, and is leading, the Discovery Farms effort. The MDA provides technical assistance and expertise in water monitoring, assistance with outreach, funding for monitoring equipment, and Clean Water, Land, and Legacy funding. The U of M Extension service assists with special projects, and provides education and outreach.
Local partnerships with soil and water conservation districts, lake associations, and other local organizations provide for the operation and maintenance of the monitoring systems.
“From a standpoint of uniqueness and originality, Minnesota is probably the only state checking water quality on fields with the cooperation of everybody mostly thanks to the cooperators,” Rehm said. Cooperators are the farmers who are willing to participate in the Discovery Farms program by allowing water sampling and collection structures to be places on their land, like Groos.
At this time, there are eight discovery farms in southern, southeastern, and central Minnesota: a turkey, corn, and soybean farm in Kandiyohi County; a swine farrowing and beef cattle farm in Goodhue County; conventional dairy farms in Stearns and Wright (the Groos Farm) counties; a no-till corn and soybean crop farm in Chisago County; a swine finishing, corn, and soybean farm in Blue Earth County; and corn and soybean farms in Blue Earth and Renville counties using conventional tillage.
Because the goal of the program is to represent the diversity of agricultural enterprises and settings in Minnesota, the program is expected to continue to grow in the coming years, according to the Discovery Farms Year in Review 2011.