Prairie Seed Mixes for Contour Buffer Strips: On-Farm Demonstration and Workshops
Research has shown contour prairie strips reduce surface nutrient runoff for about the same cost as cover crops, and do not carry the uncertainty of replanting every year. The effectiveness of this emerging conservation practice will depend on rate of adoption and continued maintenance of the practice. For landowners to consider sacrificing up to 10 percent of a crop field for nutrient reduction, they will need to see excellent examples in fields similar to theirs. A highly successful prairie planting can be achieved when carried out by experienced practitioners using a custom seed mix. Unfortunately, this expertise is not widespread enough to serve all the land that could benefit from prairie strips.
The objective of this project is a clearer understanding by producers, resource managers, landowners and farm managers about establishment costs and benefits of general versus custom-designed seed mixes, as well as best practices for establishing prairie strips.
A prairie strips replicated trial demonstrating the outcomes of general versus customized seed mixes will be established on the Iowa State University Northeast Research and Demonstration Farm near Nashua. In addition, a demonstration site on a private farm in the Middle Cedar Watershed will be established. Combined, these two sites will involve 30 acres of prairie strips treating 300 acres, comparing establishment costs and vegetation attributes of general versus customized prairie seed mixes. By the second year, up to 10 hands-on workshops offering technical training and peer exchange opportunities for landowners, technical service providers and professional farm managers, plus tours and field days, will be held.
This project addressed Iowa’s nutrient reduction goals by demonstrating the outcomes of general versus customized seed mixes in a side-by-side demonstration, plus training technical services providers. After two growing seasons, the pollinator mix generally established poorly while the diversity and economy grass mixes established well. On average, the diversity and economy grass mixes produced four times as many native stems as the pollinator mix. Native cover also was greater in the diversity and economy grass compared to the pollinator mix. The economy grass produced the fewest forbs, and forb density in the diversity mix was not significantly different from the pollinator mix. Mowing more than doubled native stem density and increased native cover by twofold. However, mowing did not affect forb density. The pollinator mix was least cost effective, with the cost per thousand stems four times higher than the diversity mix and more than 10 times higher than the economy grass mix.
A summary report of the second year Nashua research was developed. Key findings from the research are diverse, site-appropriate seed mixes (1:1 grass to forbs) established well and supported pollinator forage plants while remaining cost effective; pollinator seed mixes (1:3 grass to forbs) supported pollinator forage plants, but established poorly and were not cost-effective; grass-dominated seed mixes (3:1 grass to forb) were cost-effective, but supported very few pollinator forage plants; and frequent first-year mowing greatly increased native plant establishment and cost effectiveness for all seed mixes. Updates and improvements were made to the Iowa Prairie Seed Calculator. It is available online to help create custom seed mixes, taking into consideration such things as seeding method, planting time and planting site conditions. It can be found here: https://www.tallgrassprairiecenter.org/restoration-and-research
Participated and presented at a Dry Run Creek Watershed Improvement Project field day. The Prairie on Farms program was highlighted as well as a brief overview of the Nashua study comparing three different seed mixes and the effects of establishment mowing. Outcomes of general versus customized seed mixes in the side-by-side demonstration site were discussed. Continued to coordinate with the ISU STRIPS team to plant 10 acres of prairie strips at Roadman Farm near Dike, Iowa. Planted Phase I in fall 2016, Phase II will be planted in spring 2017. Also worked with a Black Hawk County landowner to identify location for two additional in-field prairie strips, which later were planted. Analysis of vegetation data collected from the Nashua research site continues.
Prairie on Farms field days were held in September at two locations — Dysart and Nashua. At Dysart, participants visited 10 acres of in-field prairie strips planted in 2015, then traveled to a site where 8 acres of a diverse prairie buffer were planted in 2016. Year 1 and Year 2 research was shared at both locations on the effects of first year mowing on native plant emergence and growth using three different seed mixes. New prairie plantings were coordinated at two private locations, one a 2-acre site, the other 10 acres. Vegetation sampling of stem density, cover and flower counts for native and non-native species was conducted in experimental plots at the Nashua research site. Collected data will be used for second year research project results.
Personal interviews were conducted with some attendees of four 2015 Prairie on Farms field days to gauge impact, and a report completed. Planning and advance publicity for the 2016 field days is underway. The second half of the Dike project was planted May 5, with three seed mixes used. In-field prairie strips were highlighted at a Benton/Tama Nutrient Reduction Demonstration project field day June 8. Participants visited the Prairie on Farms 2015 planting near Dysart. Planting details and logistics were discussed, and the differences in the three seed mixes outlined.
Technical staff analyzed Nashua demonstration site data for the effects of first year mowing on native plant emergence and growth using three different seed mixes. An Interim report highlighting first year results is available on the Tallgrass Prairie website (http://www.tallgrassprairiecenter.org/). Protocol for the second year of sampling at the Nashua demonstration site was created. The Iowa Native Seed Calculator was completed and is available at: http://www.jamess.com/IowaPrairieSeedCalculator-D2/. Preparations were made for spring 2016 plantings. Seven maps of the 2015 prairie planting sites and one comprehensive map of all planted sites are being developed.
Data on seedling numbers in both mowed and unmowed plots was collected and analyzed at a prairie strips replicated research trial on the Iowa State University Northeast Research and Demonstration Farm near Nashua. A four-acre prairie strip was planted with a high diversity mix in the Miller Creek Watershed on land owned by BMC Aggregate. Fall planting also was done on half of a 30-foot strip plot on land near Dike owned by the University of Northern Iowa. Three different mixes were used, with the same seed mixes to be planted in spring 2015. This site will be a demonstration on the survivability of plants and how spring and fall plantings yield different plant communities. An online seed calculator is in the website design phase.
A prairie strips replicated research trial has been established on the Iowa State University Northeast Research and Demonstration Farm near Nashua. A similar trial was established on two private farm fields near Dysart in the Middle Cedar Watershed. Workshops were held in June at Nashua and at the farm near Dysart. Conservation benefits of prairie including soil and water quality, pollinator habitat and wildlife habitat were highlighted, plus the proper seed mixes and establishment of prairie strips. Progress has been made on both an online seed calculator and an informational brochure series about prairie establishment and maintenance.
This project is designed to help producers, landowners and others better understand establishment costs, benefits and best practices for establishing prairie strips. A prairie strips replicated research trial demonstrating the outcomes of general versus customized seed mixes has been established on the Iowa State University Northeast Research and Demonstration Farm near Nashua. A similar trial is being established on two private farm fields near Dysart in the Middle Cedar Watershed. Workshops were held at both sites in early June. Development is underway on a seed mix design document, model seed mixes and an online seed calculator.