To date, we’ve seen no effects of prairie strips on yields in adjacent cropped areas. Of course, converting cropland to prairie strips will reduce the amount of land that is cropped. Payments for prairie strips from federal conservation programs and other sources can help offset this cost.

Some research suggests the beneficial insects, including pollinators and the predators of insect pests, associated with prairie strips could help boost yield within adjacent crops, but this is still an area of ongoing research.

Prairie strips provide both abundant and diverse flowering plants to agricultural landscapes, which are essential for supporting honey bees and conserving wild bees and butterflies. Flowers provide critical food resources for these insects: nectar for adult bees and butterflies, and pollen for the young bees. Furthermore, a growing body of scientific literature indicates that bee health is improved when they are provided a diverse diet of plants.

Corn and soybean crop fields also provide pollen and nectar, but only for a limited time. Once these crops stop blooming, there are little-to-no flowers left for bees and butterflies in the Midwestern landscape. Prairie strips provide a diversity of flower types, and thus food, continuously throughout the summer, including the late summer-to-fall, a critical time of the year when pollinators, especially honey bees are storing resources for the coming winter.

In addition to a diversity of flowers, Monarch butterflies require milkweed to complete their lifecycle. Adults use nectar from several flowers as food, but their larvae feed solely on milkweed leaves. We work with farmers and farmland owners to include several milkweed species in prairie strip seed mixes to help support these iconic butterflies.

There are some unanswered questions with regard to potential insecticide exposure to pollinators associated with placing diverse floral resources adjacent to crop fields. We are in the process of conducting studies to better determine the impact of insecticide use adjacent to prairie strips. But these impacts can be minimized if insecticides are applied using integrated pest management (IPM) principles and according to their labeled directions. More information can be found at ISU's website on Integrated Pest Management.

In sum, prairie strips well integrated into crop fields can help farmers and farmland owners meet multiple objectives for crop production and pollinator conservation.

Contour buffers are typically planted with fixed widths. In contrast, we vary the width of the prairie strips based on the amount of water they intercept, with the goal of treating all of the runoff leaving the crop field. Where more water is flowing down-slope, prairie strips should be wider, and where less water is flowing down-slope, the strips can be narrower.

The types of plants used for conservation buffers and filter strips can affect how they function. For example,

• Cool season exotic grasses such as smooth brome, tall fescue, orchard grass, and Kentucky bluegrass are widely used to provide ground cover in agricultural areas of the U.S. Corn Belt, but are relatively weak-stemmed and prone to laying flat under heavy rain. They are useful for grassed waterways that are intended to convey water while preventing erosion. In contrast, native tall-grass prairie communities are typically dominated by stiff-stemmed warm season grasses such as Indiangrass, big bluestem, little bluestem, and a wide range of erect forb (i.e., wildflowers) species that are less prone to collapse under heavy rain. These native plants are more effective in providing resistance to water flow and sediment movement.
   
• Typical contour buffers and grass strips are planted to monocultures of the cool season exotic grasses. For this reason, they provide less support for pollinators and potentially other wildlife. Pollinators require flowering plants, also known as forbs, for nectar and pollen that comprise their food. The best pollinator habitat as enough diversity that there are multiple species of plants in flower throughout the growing season; so, from April through September. Contour buffers planted to monocultures furthermore will not have as diverse and abundant root systems, and thus will require more time to provide soil health benefits such as breaking up compaction, improving infiltration, or raising soil organic matter. They are also less resilient to weather extremes.  

Prairie strips are a conservation tool that can be used in both conventional and organic farming operations. In conventional farming operations, precision herbicide management is useful. Native forbs (i.e., wildflowers) in the prairie strips are broadleaf plants and can be damaged or even killed by direct contact with herbicide. Once established, native grasses and forbs have deep root systems that help create a durable, resilient plant community.

Grasses such as smooth brome, tall fescue, orchard grass, and Kentucky bluegrass are widely used to provide ground cover in agricultural areas of the U.S. Corn Belt, but they are relatively weak-stemmed and prone to laying flat under heavy rain. They are useful for grassed waterways that are intended to convey water while preventing erosion. In contrast, native tall-grass prairie communities are typically dominated by stiff-stemmed grasses and erect forbs (i.e., wildflowers) species that are less prone to collapse under heavy rain and more effective in providing resistance to water flow and sediment movement. 

Monocultural plantings of smooth brome, tall fescue, orchard grass, or Kentuck bluegrass will not provide the same support for pollinators as diverse native plantings because they lack flowering plants, also known as forbs. The nectar and pollen associated with flowering plants comprise their food.

While plantings of perennial monocultures are beneficial in keeping roots in the ground for the entire year, they will not have as diverse and abundant root systems as diverse plantings. Thus more time will be required to provide soil health benefits such as breaking up compaction, improving infiltration, and raising soil organic matter. For this reason, they are also less resilient to weather extremes.

In Iowa, on-farm: Several Iowa State University Research and Demonstration Farms host prairie strips, including the Armstrong Memorial Farm near Lewis, McNay Memorial Farm near Chariton, Neeley-Kinyon Memorial Farm near Greenfield, and the Southeast Farm near Crawfordsville. These farms are open to the public for viewing during business hours. On-farm implementations of prairie strips at private farms are periodically featured at field days organized by either the STRIPS team or partner organizations. Check for announcements on this website or follow us on Twitter (@prairiestrips) to find out about these events. 

In Iowa, original research site: In Iowa, you can visit the original STRIPS research sites at Neal Smith National Wildlife Refuge, but please check in at the refuge’s headquarters, the Prairie Learning Center, for directions and other information before visiting the sites. Signs directing refuge visitors to the STRIPS sites are being developed.  Additional public sites are under development, so stay tuned!

Beyond Iowa: Beyond Iowa, farmers and farmland owners have used native species for planting in-field buffer strips among row crops, often under the USDA NRCS Contour Buffer Strip standard. We are not currently partnering to provide field tours of location where farmers or farmland owners are using prairie strips, which combine consideration watershed area and water flow paths, highly diverse native plantings (~30 species of grasses and wildflowers), and in-field contour buffer and edge-of-field filter strips. Work is underway with partners in Kansas, Minnesota, Missouri, and Wisconsin to implement research and demonstration areas with prairie strips.

If you want to plant prairie strips, we suggest you start with one of these two brochures:

• For farmers: Farming with Prairie Strips
• For farmland owners: A Landowner's Guide to Prairie Strips

These publications answer many initial questions we get from people interested in prairie strips. For more specific information, read:

• The Cost of Prairie Strips
• Installing Prairie Strips: Frequently Asked Questions
• Installing and Managing Native Prairie Plantings
• Perennial Systems Conservation: Reaching Women Landowners & Farmers
• Planting Native Prairie into Corn and Soybean Stubble
• Planting Native Prairie into Cool Season Sod (Brome, Orchard, Fescue, Bluegrass)
• Women Landowner Resource Guide

If you're still interested and would like a direct consultation, contact us at prairiestrips@iastate.edu

Prairie strips require multiple years to start looking like a prairie.

• During the first year, mowing is required. The strips will look like a short, vegetated buffer. There may be some native wildflowers, such as partridge pea or black-eyed sSusan, but it will not look like a prairie. Native species put most of their first-year energy in their roots and will not produce significant above-ground biomass.
• During the second year, early species (i.e., Canada wild rye, partridge pea, black-eyed Susan, evening primrose) will be recognizable and may bloom. Unless there is considerable weed pressure, mowing is not necessary. Spot spraying can be used in year two if there are weedy areas.
• By the third year, most prairie restorations will begin to resemble a diverse native tallgrass plant community. Find out more about mowing below under How do I take care of my prairie strips?

If establishing prairie strips into cropland that has been treated with herbicides other than glyphosate, a pre-strip establishment plan may also be necessary. For example, modifying the weed-control plan for that area or planting a cover crop for a year. The STRIPS team is actively researching options for this situation.

Prairie can be planted several times throughout the year. It is preferable to seed in either the fall after harvest, or the spring, before or after planting (but before June 30 in Iowa). Midsummer is generally not a good time to plant. Prairies include two basic types of plants, forbs (i.e. wildflowers) and grasses. Forbs benefit from the cold wet stratification an Iowa winter provides, and like a fall seeding. Prairie grasses should be seeded in greater volume for a fall seeding, as their germination rates suffer from predation and exposure. Dormant, or winter seedings also can be successful.

There are numerous native seed dealers and technical service providers throughout Iowa and the Midwest. The Plant Iowa Native website has a comprehensive list and contact information for seed sales and technical service providers. The Tallgrass Prairie Center also maintains a Iowa Prairie Seed Calculator, which is helpful in suggesting seed mixes based on location, species preferences, and cost.

The number of types of prairie plants sown (“species richness”) and the amount of each type that is present in seed mixes is a management decision. How the plants will function and the seed mix costs are two primary considerations.

• Grass seed is generally cheaper than forb (i.e., wildflower) seed, but forbs are key components of prairie communities that supply pollen and nectar as important foods to pollinators and natural enemies of crop pests. Grasses have fibrous root systems, whereas prairie forbs often have deep taproots; thus, both types of plants play complementary roles in the soil environment.
   
• The most basic seeding mix for the Conservation Reserve Program (CRP) contains only two forb species that comprise less than 5% of the seed mix, and these mixes often cost less than $100 per acre. Alternatively, forb-rich seed mixes that include rare species can cost over $1,500 per acre. There are a large number of moderate-diversity prairie seed mixes that cost about $250 per acre.
   
• The source and harvest method also affect seed-mix prices.

We estimate that the average annual cost of converting one acre of crop land to prairie ranges from $230 to $293 per year, depending on the prairie seed mix and cost of land. Protecting a field with prairie strips using a "10% solution," where one acre of perennial prairie protects 9 acres of cropland costs between $26-$33 per acre per year (assuming a pre-mixed [economically priced] CRP CP25 seed mix is used). These costs are explained further in our extension publication: The Cost of Prairie Strips.

Most costs associated with prairie strips occur upfront with establishment, both the cost of the prairie seed as well site prep, planting and mowing that go along with establishment. The basic seeding mix for the Conservation Reserve Program (CRP) contains only two forb species that comprise less than 5% of the seed mix, and these mixes often cost about $100/acre. Alternatively, forb-rich seed mixes that include rare species can cost over $1,500 per acre. There are a large number of moderate-diversity prairie seed mixes that cost less than $250 per acre. The source and harvest method also affect seed-mix prices. Planning your seed mix well in advance of planting can help with keeping seed costs low.

Various organizations provide cost-share dollars that can reduce these costs, including but not limited to:

• USDA Farm Service Agency (FSA) offers annual, cost-share, and in some cases incentive, payments through Conservation Reserve Program (CRP) 10 or 15 year contracts. Under a 15-year CRP contract for CP-43 Prairie Strips, farmers could receive a total cost reduction of approximately 75 percent, thus costing about $8 per year per crop acre treated with prairie.
   
• USDA Natural Resource Conservation Service (NRCS) Environmental Quality Incentives Program (EQIP) may assist with prairies to be harvested or grazed, depending on the county.
   
• U.S. Fish and Wildlife Partners Program works with landowners to restore wildlife habitat.
   
• Iowa Department of Natural Resources' Resource Enhancement and Protection (REAP) awards small grants for soil and water protection.
   
• Pheasants Forever funds habitat projects including its Native Seed Program.
   
• Trees Forever funds Pollinator Habitat Conservation projects in Iowa and Illinois.

This Iowa State University website hosts a decision support tool that can help estimate the specific costs of placing prairie strips or other conservation practices on your farm.

The Plant Iowa Native website has contact information for seed sales and technical service providers.

While this is still an active area of research, there are a few guiding principles we can draw upon to try to maximize water quality gains.
 

• For potential pollutants that are moving with water across the land surface, we want to make sure we provide the greatest protection – the area in prairie strips – where we have the most runoff. In other words, we make sure we are providing greatest protection in areas that receive the most water flow.
   
• Placing the leading edge of our prairie strips perpendicular to the primary pathway of water flow provides the best chance to slow water flow, improve water infiltration, and remove any potential pollutants that are moving with the water.

As water moves downslope in a field and encounters the prairie strips, there will be greater resistance to flow and the surface runoff water will slow down. When this water slows, some of the material it is carrying will be deposited. This generally occurs a few feet into the leading edge of the strip or immediately upslope of the strip.

How quickly the soil builds up is in large part dependent on upslope practices. Incorporating good conservation systems within the row-crop area can reduce sediment loading to the strips and thereby reduce sediment deposition along the leading edge of the strip.

Over time, there may be some required maintenance to regrade deposited sediment to minimize any potential for short-circuiting of water flow.

Research as part of our project and other research on buffers and riparian buffers has found that when shallow subsurface flow interacts with the root zone under the prairie strip or other buffers, we can see significant reductions in the concentration of nitrate-nitrogen.

• There may be settings where the shallow subsurface flow is below the root zone such that there is little impact on nitrate-nitrogen concentrations. In situations where fields have extensive artificial subsurface drainage networks the nitrate may be moving below the prairie strip or buffer in the tile. This would reduce any water quality benefits relative to subsurface flow of the prairie strip or buffer.
   
• There is encouraging research for nitrate-nitrogen reduction using ‘saturated buffers'. This is installation of a tile line along the leading edge of a prairie strip or buffer to promote shallow subsurface flow within the active root zone of the prairie strip or buffer.
   
• In situations where natural subsurface flow pathways interact with the shallow rootzone below the prairie strip or buffer and where we see nitrate-nitrogen concentrations reductions, it is difficult to quantify the overall load reduction since there are not good measures of the quantity of water flow moving through this pathway. In the future we want to examine additional settings to better understand water quality benefits relative to subsurface water flow.

Perforated tile are buried under cropland to remove excess water detrimental to crop production. Farmers and landowners considering installing strips of prairie plants in their fields have asked about the possibility of roots growing into tile lines. To address this potential, Tim Younquist and Matt Helmers used video cameras to evaluate root penetration into the tile lines under prairie and continuous corn. 

This news release and video summarize their results. Prairie and continuous corn showed similar levels of root growth and structure. The largest roots encountered were cottonwood tree saplings, which were growing in the prairie. Farmers or farmland owners implementing prairie strips will recognize the importance of managing such woody encroachment to avoid their roots encroaching into tile.

Sometimes farmers report finding a tile plugged with herbaceous roots in low-lying areas or along stream corridors. The usual cause is reed canary grass, an aggressive non-native plant naturalized in the Iowa landscape that is not seeded in prairie plantings.

Maintenance will vary from site to site, but multiple mowing of the prairie strips in the first year is required to help with establishment. Prairie seedlings put a majority of their growth in their roots in the first year and will still be small seedlings by the end of their first year. It is necessary to mow the strips to control annual weeds or a nurse crop planted along with the prairie seeds in order to provide the small prairie seedlings with an opportunity for sunlight.
 

Care by year:

• During the first year, prairie strips should be mowed consistently to a height of 4-6 inches. When the plants in the strips  have gotten about knee high, it means it is time for mowing. Maintenance mowing will result in faster establishment and a more diverse prairie.
   
• In the second year, maintenance mowing and/or spot application of herbicide may be required.
   
• By the third year and thereafter, maintenance will consistent of spot application of herbicide as needed and baling or prescribed burning of the strips if desired.
   
• If prairie strips become dominated by weeds or invasive species, maintenance mowing and application of herbicide can be used to control them. Weeds and invasive species can be held in check by planting a diverse mix of native species in the initial planting and mowing the strips in the first year.

There are numerous sources of  in-depth information on prairie establishment and management. We find these sources especially helpful:

• The University of Northern Iowa's Tallgrass Prairie Center. There website hosts numerous informational brochures.
   
• The book, A Practical Guide to Prairie Reconstruction, by Carl Kurtz.
   
• The book, The Tallgrass Restoration Handbook for Prairies, Savannas, and Woodlands, edited by Stephen Packard and Cornelia F. Mutel.

Most prairie plants will not become weeds in crop fields where annual crops are grown and subjected to conventional weed management practices.

Prairie plants can be competitive once they become established, but most take multiple years to become established. On land that is regularly tilled or where herbicide is applied at least annually, it is unlikely that the prairie plants will become established. Prairie plants have the potential, however, to become established in no-till fields if herbicides are not used.

• During establishment, prairie strips are likely to contain annual weeds, such as foxtail, waterhemp, lambsquarters, horseweed, velvetleaf, and ragweed (giant and common), which germinate from the soil seed bank. If the prairie strips are mowed regularly during the establishment years, the amount of weed seed that is produced and spread to the neighboring cropland can be minimized. If the weed seed bank is low on the site where the prairie is established, the potential for weed seed spread is even lower.
   
• As the prairie becomes established – after the first or second year depending on the existing seed bank – the number of annual weeds will greatly decrease, and the prairie should no longer be a source of annual weeds for neighboring cropland.
   
• Prairie strips also may be susceptible to invasion by perennial weeds, such as Canada thistle, which could then spread into neighboring cropland. Spot spraying with herbicides is an effective strategy for suppressing perennial weeds in prairie strips, particularly as prairie plants mature and become more competitive with the weed species. Perennial weeds can be controlled in annual row crops by applying herbicide or tilling.

Driving on prairie strips will create disturbance and could disrupt the native plant community. Many invasive weeds are more tolerant to disturbance than prairie plants, and driving on the strips could create an environment where weeds can out-compete the prairie plants. Disturbed areas also may reduce the prairie diversity to only a few native species.

Palmer amaranth is a noxious and aggressive weed you should keep watch for in your crop environment, but you need not be overly concerned about it in your prairie strip.

Around 2016, Palmer amaranth was unintentionally brought into Iowa on agricultural equipment and within seed mixes for native plantings as well as in cotton seed and gin trash used in dairy rations. Additionally, some seeds of this species could have come in via hay and/or livestock bedding. It's arrival is  concerning because it is difficult to control in the crop environment and can negatively affect production.

The good news is that native seed dealers now know to watch for out Palmer amaranth and work keep it out of their mixes. Using local ecotype seed -- seed grown within 100 mi north/south and 200 mi east/west of your planting site -- reduces the chance of receiving seed contaminated with Palmer amaranth (while also improving the establishment success of the native plants). Furthermore, Palmer is an annual, not a perennial like the native plants that comprise prairie strips, and with diligence it can be eradicated from any given site. And finally, the Palmer amaranth that did show up in Iowa did not appear to have cold-hearty seeds. As long as Iowa's winters are cold, this weed does not appear to be a big problem here compared to the Southern US.

Resources are available to help identify and eradicate Palmer amaranth. The ISU Extension Store hosts a brochure and accompanying video to assist with differentiating Palmer amaranth from related species in Iowa: waterhemp and other problematic pigweeds. Early detection is imperative for stopping this weed.

The first defense against Palmer amaranth and many other aggressive weeds within your native planting is to purchase amaranth-free prairie seeds from a reputable seed dealer. Reputable seed dealers will regularly scout their production fields and remove weedy plants before they go to seed.

The second defense against Palmer and other aggressive weeds is to establish a competitive stand of native plants. This STRIPS brochure summarizes the steps needed to do so. Regular scouting and mowing during the establishment phase are critical to establishing the desirable native plants, and preventing weeds like Palmer amaranth from reproducing. Once the native prairie community is well-established, there is little to no room for annual weeds to take root and grow. Well-established prairie communities commence growth in the spring before Palmer amaranth germinates and will continue to compete effectively against annual weeds year after year.

If you believe you have Palmer amaranth, this USDA NRCS Tech Note, Eradicating Palmer amaranth on Tallgrass Prairie Restorations, details the steps to eradicate the weed. We encourage you to seek guidance from local USDA NRCS Field Office staff, ISU Extension Agronomists, or a Certified Crop Advisor. 

Yes, the herbicides you use on your crops matter, especially when you are trying to establish prairie strips. Many alternatives to glyphosate will last in the soil for more than one season. There are planting restriction guidelines provided by manufacturers and you can refer to these to find out how long a herbicide will last and what crops are sensitive to it. (Prairie seedlings aren't listed separately, but would respond much like small grains, alfalfa, and clovers.)

The Crop Data Management Systems, Inc. website provides a database of herbicide labels that can be searched using either the common name of the herbicide or the product manufacturer. Follow the links at the top of the page for ‘Label Database’ and then search via product name or manufacturer.  

You also can compare different herbicides using a table from the 2015 Weed Control Guide for Ohio, Indiana and Illinois. View or download their “Restrictions on Crop Rotation” table here [PDF].

Spray drift definitely can harm the prairie strips in the first several years as the young plants are establishing, but mature prairie plants are more resilient. Mature perennial plants have deep root systems with substantial stored energy reserves, which tend to allow them to bounce back from incidental drift.
 

Planting a diverse mixture of native plants also helps, as different plants will have different life cycles. For example, while some early growing-season plants might experience some die-back with spray, later-season plants can grow up and take their place. Regardless, we always recommend minimizing herbicide spray drift.

Prairie strips could serve as a source of hay if harvested later in the summer, but the plant species composition may shift. Managers may find it difficult to maintain a diversity of grass and forb species.

An alternative harvesting strategy is to wait until after a killing frost, when prairie species have moved many of their nutrients into their roots or have dispersed their seeds to foster a future generation of plants. Harvesting prairie strips in mid-to-late fall can provide a sizable amount of low quality hay and/or livestock bedding, without strongly altering species composition.

This is an open question for the STRIPS team, which we hope to answer soon. At least two of our farmer cooperators are planning to graze their prairie strips: one is developing a method to rotationally graze the prairie strips and another releases cattle onto his whole field after fall corn harvest. Stay tuned for research results; in the meantime, you might try it, being careful not to allow livestock to congregate in any area long enough to create bare ground.

Butterflies and bees are attracted to the colors and scents of flowers within the strips. Flying above the crop pollinators will be able to locate the strips using these cues.

Will field pesticides kill the butterflies? Many people wonder if butterflies and other pollinators will die when they get to the strips, and they wonder about the impact of treated seed on species in the strips. These questions stem from research documenting the negative effects on pollinators of a class of insecticides commonly known as neonicotinoids that are used as seed treatments on both corn and soybean. These insecticides are moved inside the plant tissues and even into the pollen and nectar on which pollinators feed. At this time there is insufficient research exploring the levels of this type of contamination in the strips, but we are working toward answering these questions with current research.

This is a question we’ve discussed in the STRIPS team but we don’t have data to answer. A prairie specialist with the US Fish and Wildlife Service, Pauline Drobney, suggests that the following list of species might perform well in grass waterways. These species protect soils but do not impede water. We recommend planting at least two or more species to ensure against unforeseen circumstances (e.g., drought, disease). We hope we can test these species for performance.

• Dropseed (Sporobolus asper) - A grass that is readily available from seed dealers and establishes easily. It forms a clonal mat and grass should lay down nicely, though flowering stalks are stiff, probably in a similar way that brome flowering stalks are stiff. The roots hold soil well.
• Muhly (Muhlenbergia spp.) - This genus offers multiple species that could be excellent candidates for waterways.
• Nimblewill (M. shreberi) could be especially good as it grows easily and is definitely a soft "flowy" grass that would really lend itself to this application. It is durable, tolerates mesic, dry-mesic or wet conditions, and sun or part shade, and can co-exist with Kentucky bluegrass. It withstands drought. Eilers and Roosa (The Vascular Plants of Iowa) list this as frequent in the southeastern two-thirds of Iowa.
• Marsh muhly (M. racemosa) is listed as "frequent to common throughout" Iowa (Eilers and Roosa), and is a pretty agreeable plant too. It is a bit coarser than nimblewill, but would likely do well in this application too.
• Side oats grama (Bouteloua curtipendula) – This could be a good species for this application. It tends to clone and would likely lie down with rain, though it might have more flowering stalks and perhaps be stiffer than others; but maybe not. Some people use this species for lawns, and if mowed, apparently it forms a kind of soft ground cover.
• Panic grasses (Dichanthelium spp.) could be very good for this application as they are typically shorter and can form mats. This genus is not very available from seed producers, however.
• Several species of sedge (Carex spp.) would be excellent for this as well.
• There might be some wildflower species that could fit the bill as well, but we don’t usually think about forbs in these situations. It might be fun to try!

There are many ways to get more information about prairie strips. This website, www.prairiestrips.org, is a good place to start for these items:

• Technical guides prairie strip establishment, management, and costs can be found here.
   
• Videos can be found on Vimeo.
   
• Field days: We periodically offer field days, advertised on our News pages.
   
• Live updates: Follow @prairiestrips on Twitter to keep up with recent developments.
   
• Published research: Our scientific publications also are listed on the Publications page, but you may or may not be able to access these without paying a publisher’s fee. Contact us directly if you would like access to a specific research paper.
   
• Contact us: You can contact the STRIPS team at prairiestrips@iastate.edu.