Principal Investigator: Adam Birr and Jeff Strock
Organization(s): Minnesota Corn Growers Association; University of Minnesota Southwest Research and Outreach Station
Sponsor: MPCA 319 Funds
Award Amount: $183,766
Start Date: 4/26/2010 | End Date: 8/29/2014
The final report is available through the Minnesota Water Research Digital Library
Quantify the water quality and quantity characteristics of perennial vegetation on undisturbed soils and compare it to agricultural management practices commonly used in southwestern Minnesota.
Data quantifying the soil and water characteristics of perennial vegetation on undisturbed soils are very limited in Minnesota and in the Midwest as a whole. Typically studies have focused on such features as grass filter strips or have been conducted at a scale where water quality effects are confounded by multiple variables. This study will measure surface runoff characteristics of perennial vegetation on a hillslope of undisturbed soils using two different research designs.
Why is this important?
Many Total Maximum Daily Load (TMDL) implementation plans include the establishment of perennial vegetation, or the use of land set aside programs, to remediate pollution in the agricultural landscapes of southern Minnesota; however, the quantification of the water quality benefits of such programs as the Conservation Reserve Program (CRP) at the field scale is lacking. Best management practices designed to reduce sediment and nutrient export from agricultural watersheds will be more effective with a better understanding of the vegetation, soil, management and hydrologic controls that link spatially variable sediment and nutrient sources and sinks to transport processes at the field scale.
The Hick’s Farm, located in Redwood County, includes a 160 acre field comprised entirely of perennial vegetation that has been part of the family farm since 1857. According to the family, the field was never planted with conventional row crops and no subsurface drainage has been installed. The field has not been grazed in over 20 years; however, the family does harvest the vegetation for forage approximately once per year. The perennial vegetation is composed primary of smooth bromegrass with a Kentucky bluegrass understory. Native forbs and grasses are also present; however, the native species make up a small amount of the overall plant diversity.
A hillslope located at the southern edge of the field was subdivided into three discrete drainage areas referred to as “watersheds” for the purposes of this study. Two of the watersheds are composed entirely of perennial vegetation (0.79 and 0.98 acres in size). A third watershed (1.7 acres in size) has approximately 0.67 acres utilized for long-term conventional row crop production that drains onto the perennial vegetation on the hillslope.
The Hick’s Farm is located within the Cottonwood River Watershed, a tributary of the Minnesota River. Soils in the study area consist of well drained loams and clay loams indicative of the region. The undisturbed soil at the site is classified as a Storden loam.
Analysis was completed to further examine how much of the greater Cottonwood River Watershed was composed of lands with similar slope that may serve as potential treatment areas to mitigate non-point source pollution between agricultural areas and floodplains. This analysis provided context for our results in terms of applying findings to a broader area. The majority of the land (88.2%) in the Cottonwood River Watershed has slopes under six percent; approximately nine percent of the land in the Cottonwood River Watershed was similar to the project site (slopes of 6 to 12%). The proper placement of perennial vegetation for water quality benefits within a watershed will be critical for maximizing the return of such programs.
Summary results are below. The complete project reports will be available on this page in early 2015.
Paired Watershed Design
Note: NVe was converted to row crop production while the control watershed, NVw, remained as perennial vegetation on undisturbed soils.
Soil Bulk Density
Above and Below Watershed Design
Bill.Vanryswyk@state.mn.us ~ 507-344-5260
Supervisor, Clean Water Technical Assistance Unit
Margaret.Wagner@state.mn.us ~ 651-201-6488