Comparing Prairie Grass – Small Grain Straw for Mulching Vegetable Crops

Project Overview

FNC08-742
Project Type: Farmer/Rancher
Funds awarded in 2008: $2,107.57
Projected End Date: 12/31/2011
Region: North Central
State: Wisconsin
Project Coordinator:
Tony Ends
Scotch Hill Farm

Commodities

  • Agronomic: oats, wheat
  • Vegetables: beans, brussel sprouts, cabbages, sweet potatoes

Practices

  • Pest Management: mulches - general, mulching - vegetative
  • Soil Management: soil quality/health

    Summary:

    [Editor’s Note: To see the report with photos and tables in their original format, open the PDF version of the report. This version contains text only.]

    Project Participants: Dr. Jim Stute, UW Rock County Extension Crop Specialist; Brian Benzow, Wisconsin Department of Natural Resources

    Field Trial Summary

    In a 2010 field trial with high and low foot traffic vegetable crops, switch grass straw mulch compared well with oat and wheat straw, deterring weeds with similar effectiveness. This prairie grass straw in the study, however, showed two important advantages over small grains straw: roughly double the tissue nitrogen content and a much lower carbon to nitrogen ratio. These differences should affect the rate of material decomposition since the C:N ratio is closer to the 30 to 1 ratio required for microbial breakdown.

    Background and Need: Economics, Ecology, Sustainability

    Intensive, diverse organic vegetable crop production relies heavily on manual labor, especially for controlling weeds. As scale increases, hand labor can easily dominate production expenses. Some Community Supported Agriculture growers in the Upper Midwest, for instance, spend one-third of their gross receipts on labor.

    Community Supported Agriculture (CSA), which brings consumers as subscribers or “shareholders” into direct market relationship with growers, spawned from a pair of such operations on the East Coast in the 1980s. It now numbers more than 4,000 largely vegetable crop initiatives of widely varying sizes in the United States on the Local Harvest web site. CSA is helping revive local, direct market fresh vegetable production in many urban and suburban areas nationwide.

    To individual CSA growers, controlling labor costs through reliable, cost-effective methods of weed suppression has become vitally important. An advanced CSA grower must typically budget or provide for one adult worker full time per one acre to one acre-and-one-half of vegetable crop production.

    Rolled plastic mulch from polyethylene film has increasingly helped vegetable crop farmers control weeds since the 1950s. By 1999, the practice had spread globally to more than 30 million acres, with some more recent estimates of such plastic mulch use estimated to cover more than 2,500 miles of crop production around the world. Tracking plastic mulch use has proven difficult, but much of these mulches do end up in landfills at season’s end. This adds disposal fees to production costs and raises environmental concerns.

    Mulches conserve soil moisture, prevent erosion, cut soil compaction and eliminate root damage, which deep cultivation or hoeing may cause. Their weed suppression cuts labor expenses, too, though removing plastic mulches at season’s end requires at least 8 hours of manual labor per acre (McCraw, D. Motes, J.E. 2007, Oklahoma University Cooperative Extension).

    Extracting and disposing of plastic mulch after the growing season poses challenges for most growers. Photodegradable and biodegradable plastic mulches, made from such alternatives as cornstarch or coated paper, have been and are being developed and studied. Washington State University researchers at Vancouver evaluated 10 alternative mulches in a field study in 2006 and 8 in 2007, comparing all alternative mulch products to black plastic mulch.

    A trans-disciplinary research and extension project on Biodegradable Mulches for Specialty Crops Produced Under Protective Covers (Reference No: 2009-02484; funded by NIFA’s SCRI program) is determining whether experimental spun-bond non-woven mulch and leading commercially-available biodegradable mulches are of similar quality to conventional black plastic in both high tunnel and open field specialty crop production. It is also examining whether they can safely bio-degrade in the soil. In this 3-year study, a team of 17 scientists is evaluating biodegradable mulches in tomato production in three U.S. regions (http://mtvernon.wsu.edu/hightunnels/mulch.html )

    The Plant Polymer Research Unit of the USDA National Center for Agricultural Utilization Research in Peoria, Ill., has also been investigating utility of bio-plastic mulch films for biodegradability and functionality. Its lead scientist anticipates a field trial with orchards and strawberries in 2012. The unit indicated products already on the market from manufacturers can be found at:
    • http://www.biobagusa.com/Content/MulchReport.pdf
    • http://www.ferro.com/Our+Products/Specialty+Plastics/Plastic+Colorants/Markets/Agriculture/Mulching+Films.htm http://www.suntexcp.com/Imaflex-Brochure.pdf
    • http://ir.metabolix.com/releasedetail.cfm?releaseid=334775 (Mirel bioplastic)
    • http://www.omnexus.com/lod.aspx?preview=157 (presentation online for PHBs)
    • http://perfectbioplast.com/technology.htm
    • http://www.google.com/patents/about/5866269_Agricultural_mulch_with_extended.html?id=BhYXAAAAEBAJ

    Concerns noted in and from some of these studies relate to: the ability of the biodegradable mulch alternatives to meet national organic standards; residues the mulches may leave behind after degrading or inability of some mulches to completely degrade; and the effectiveness of some alternative mulches for longer-season vegetable crops, which broke down before season’s end.

    On-Farm Research Objective of this SARE Study

    Scotch Hill Farm has operated as a Community Supported Agriculture vegetable crop and small-scale livestock farm in southern Wisconsin since 1994. Starting with just 5 subscribers and growing gradually to serve more than 200 households by its 15th year, Scotch Hill now depends for 90 percent of its farm income on production of more than 100 varieties of fresh vegetables.

    The farm has employed a variety of mulching methods to control weeds and keep down labor expenses. Black plastic was a primary means of mulching vegetable crops for 11 years and is still used. Straw mulch has been used increasingly for 4 years. The farm has always relied on organic methods of production, but became certified organic only 2 years ago.

    Black plastic mulch cost Scotch Hill Farm $155 for a 4-foot-by-2,400-foot roll in 2008 before this study. A single worker at the farm (on a tractor with a secondhand mulch layer purchased for $450) has been able to apply black plastic to an entire field of 100- and 200-foot beds for vegetable transplants. This mechanical application can be completed in half a day, leaving driving paths of perennial grasses between 4- or 6-row sections, which we then mow during the growing season.

    While this has been the most cost-effective means of weed control for Scotch Hill, organic certification standards require plastic mulch to be completely removed annually from fields. Removal can become a long, labor-intensive process that runs into cold weather, or even the following spring.

    Black plastic mulch also does not always allow rain to penetrate to vegetable crop roots. It is petroleum dependent for its manufacture and has raised consumer concerns about leaching of toxic substances into soil. Plastic mulch cannot be recycled, leaving millions of tons from commercial vegetable grower use destined to landfills annually.

    In this SARE study, Scotch Hill growers Dela and Tony Ends compared performance of prairie grass straw to oat and wheat straw as organic mulch alternatives to black plastic for fresh market production of a variety of vegetable crops. We also compared our own experience establishing 3-to-5-acre fields of oats, wheat and prairie grass and their integration into our primary production and rotation of vegetable crops. Mulch comparisons for this study were made in the 2009 and 2010 growing seasons.

    2010 Project Field Trial Approach

    A field trial was conducted on Scotch Hill Farm near Brodhead Wis., in 2010, with UW Rock County Extension Agent Jim Stute. Three mulch materials (oat and wheat straw and prairie grass straw) were compared in two systems: high traffic (tomato) and low traffic (Cole crops).

    Individual rows were mulched on both sides with a specific straw type at a rate of approximately 1 bale per 40 feet of linear row on June 2. Tomatoes were trellised on 3-foot centers, Cole crops grown in rows on 1-foot centers. Other than mulch type, normal cultural practices were used in both systems.

    2010 Field Trial Measurements included:

    1 Straw composition
    2. Weed density 40 days after mulching. Weed measurements were taken within three random 2.5 square foot areas within each mulch type. Measurements included weed number, average height, species present and an estimation of predominant species. Beds were hand-weeded following rating.
    3. Visual assessments of mulch performance (as a weed barrier, persistence) throughout the growing season.

    2010 Field Trial Results:

    I. Straw composition

    Results from pre-placement material sampling are shown in table 1. Prairie grass is noticeably different from the straw in 2 measurements: 1) roughly double the tissue nitrogen content and; 2) a much lower C:N ratio. These differences should affect the rate of material decomposition because the C:N is closer to the 30:1 required for microbial breakdown.

    II. Weed density

    Weed density was only measured in the Cole crop trial because the trellised tomato trial had developed complete canopy over the row when the measurement were take. Weed density data is shown in table 2. Weed species penetrating the mulch in 2010 included foxtail, small flower galinsoga, Venice mallow and lady’s thumb smartweed. These common broadleaves should be considered more of an issue than foxtail because of their potential size and ability to compete for resources. Smartweed is also an attractant for Japanese beetles, a particularly problematic insect pest for horticultural production in southern Wisconsin.

    Prairie grass had a greater weed density than the straw materials, approximately 4 plants per 3 ft2, which consisted of foxtail. In general, the type of mulch did not impact the predominant weed species or individual weed species height, indicating that all 3 were equally effective in delaying the emergence of weeds.

    When volunteers are included, oat straw had the greatest total weed density, and volunteer plants equaled the native weed populations. This volunteer potential is undesirable. Although relatively easy to remove, the volunteers are robust, competing for resources. They also may harbor a variety of rusts, which may serve as a late-season disease reservoir for other crops.

    Figure 1. Mulch materials at application, June 2, 2010.

    Top: Wheat straw; Middle: Oat straw; Bottom: Prairie grass

    Figure 2. Prairie grass mulch, 40 days after application.

    Visual assessment of mulch performance

    The 2010 growing season represented one of optimal conditions for weed growth and competition due to the combination of ample rainfall and high temperatures. Observations of the field trial with specific varieties mirrored grower observations across a wider variety of vegetable varieties in the growers’ broader comparison over the 2009 and 2010 growing seasons.

    During this time, Scotch Hill used straw to mulch garlic, broccoli, snow peas, cauliflower, tomatoes, cabbage, melons, cucumbers, squash, sweet potatoes and three varieties of beans. For all varieties of straw mulch employed, their ability to suppress weeds seemed largely a function of how quickly we applied the mulch after seeding or transplanting, and how thick and thorough was the mulch application.

    Our farm acquired a two-row mechanical transplanting implement, three-row Planet Junior seeding equipment for 40 varieties of seed and a slower-geared diesel tractor for vegetable crop production in 2010. We had previously done all transplanting of vegetable starts and most direct seeding of vegetables by hand or with walk-behind equipment.

    The newer equipment has meant that bed preparation, scale planting and transplanting and mulching can all take place in the same day, which has greatly improved performance of all three types of straw. Previously, when the growers used straw mulch instead of black plastic, application came later when time permitted and labor was available. All three types of straw effectively deterred a wide range of weed types, excepting Canadian thistle, in each of these vegetable varieties in the two growing seasons of this study.

    Beds for our various varieties of vegetables mulched with the three straw varieties ranged from 40 feet to 300 feet in length, in double rows of plants about 3 feet wide. The snow peas and tomatoes were trellised in single and double-rows respectively. We have also begun trellising cucumbers, planted in early spring in high tunnel greenhouses. In the 2009 season, squash was planted in hills, “three sisters” style around pole beans trellising on sunflowers or sweet corn. In 2010, squash was planted with the mechanical seeder in double rows and cultivated mechanically.

    Walking paths between double rows of vegetables were either mulched with straw or sometimes mowed with a push mower. Straw mulch was also used in walking paths between black plastic beds of transplants. Prairie grass straw seems to hold up better under high foot traffic, where harvests are repeated every few days or daily (such as tomatoes or beans) than do oat and wheat straw mulches.

    Scotch Hill has also used straw mulch in two high tunnel greenhouses, built in 2008 and 2010, where the straw is put down in some paths to deter weeds and stored along east and west walls as an extra barrier against cold. The bales are then close to surrounding vegetable crop beds at the next season’s planting.

    Straw Mulch Lessons and Tips

    The longer term the vegetable crop plant variety, the more likely all types of straw mulch will eventually succumb to weather, deteriorate and allow some weeds to compete with the vegetables. If applied immediately after planting or transplanting, though, each type of mulch seems to last long enough for the vegetables to establish and develop a canopy.

    Wheat straw seems to hold up best over winter as a mulch for garlic, planted in fall and harvested the following July. Prairie grass straw mulch seems to last the longest during the regular growing season. No straw works very well in delicate, dense leafy crops, such as leaf lettuce mix or spicy greens mix. The straw catches up in the growing greens and makes a clean harvest difficult and time-consuming in post-harvest handling.
    Mulching with straw immediately after transplanting from greenhouse to field is extremely important. We were able to do that this past growing season with sweet potatoes, for instance (a longer-term crop), and we had to weed only once by hand between transplanting and harvest. We also mulched 1,000 cabbages immediately after transplanting, which greatly improved cabbage performance this season.

    Dense straw around early transplanted vegetables can help protect the tender young starts from sudden plunging temperatures and frost. With floating row cover, such as Agri-Bon, this can be effective protection against mild frost occurrence, but not a hard freeze.

    Too dense of straw mulch around plants, in varieties ranging from sweet potatoes to beans, has given cover to chipmunks, moles and field mice, which then robbed us of vegetables and cut our yields.

    Neighboring cats and Jack Russell terriers can help remediate this problem, but only when mulch is not too dense. Too little mulch allows weeds to quickly overcome any type of straw.

    We’ve experienced some volunteering of small grains and prairie grass in the straw – both during vegetable production and after we harvest, retire the beds and incorporate plant matter into the soil.

    This seems to happen most with the oats and least with the switch grass, as shown in the field trial. Soil tilth and fertility, however, seem to greatly improve from the volunteer plants, especially with oats. The volunteer plants do not get very high, certainly not as high as many varieties of weeds, nor are their root systems as troublesome as many types of established weeds and grasses. They do not advance with great density in their own straw mulch and are not difficult to remove.

    Weed growth in straw mulched beds is most vigorous immediately around vegetable starts, much more so as weeks advance than we’ve seen in most black plastic mulch use. This vegetation is easily removed by hand at harvest, and isn’t usually very time-consuming.

    Application of straw mulch, even by hand, is generally much less time-consuming than even a single weeding of most varieties of vegetables. In periods of ample rain, we had to weed beds of vegetables 4 and 5 times over a growing season before we began using any type of mulch. As our scale increased, we would lose some beds to weeds because we had not enough help to keep up with cultivation, harvests, replanting, sales and livestock responsibilities simultaneously mid-season.

    Prairie grass straw seems to hold up better under high foot traffic in vegetable beds. We’ve also used this straw effectively to mulch paths between beds of black plastic mulch, saving us push mower time and expense. We mow driving paths fairly quickly with a tractor and large rotary mower.

    Straw for mulching vegetable crops usually ranges from 7 to 10 tons per acre, but is under 5 tons per acre at Scotch Hill Farm, which employs and mows grass paths between mulched beds. That is at a rate of 250 to 300 bales per acre of straw mulch, depending on the size of the bales. We plant a wide variety of vegetables in beds on 8 or 9 acres each season, not including another 4 or 5 acres of sweet corn each year, which we have never mulched.

    Straw in bulk sells in our area for about $3 per 40-lb. bale. Garden supply houses locally get $5 to $7 per bale for small quantities of wheat straw bales that home gardeners purchase. Scotch Hill straw production expenses run under $1 per bale, depending on highly variable prices of gasoline, locations of rented fields in given years and whether we pay for field help or can rely on volunteers and farm interns.

    By comparison, the most recent FarmTek Growers Supply catalog at the time of this writing lists black plastic mulch at about $146 for a 48-inch roll, 4,000 feet long. That would accommodate 20 double rows, 200 feet long. Even with increasing straw mulch use, we are still using several rolls of black plastic mulch this size each season, especially to provide extra warmth to help some long-term transplants through a cool, early spring, and to outlast weeds throughout a growing season for long-term plant varieties.

    Prairie grass and small grains establishment

    Timing for switch grass seed harvesting (September in southern Wisconsin) and the prairie grass straw harvesting (early November here), can help spread labor for a vegetable crop farm.

    When we plant small grains, winter wheat (late September, early October) or oats as a nurse crop to hay (late March, early April) we are typically pressed with regular season vegetable crop production.

    Small grains and straw harvests (July) also prove challenging for us, during mid-season vegetable harvests and delivery. Cultivation of sweet corn and baling of hay also come at this time.

    Both planting and harvesting of the fine switch grass seed must be done with specialized equipment. The Wisconsin Department of Natural Resources provided their native species seed planting drill for our establishment of a little less than 4 acres of prairie grass. They regularly provide this service free to landowners, who usually partner with groups such as Pheasants Forever to cover seed costs of restoring wildlife habitat and conservation plantings.

    Preparing a field for planting switch grass is not much different than for small grains in an organic system. The notable differences are that the oats and wheat are annuals, the switch grass a perennial, and that the prairie grass can be managed for 10 years or more once established (a process that takes 2 to 3 years of multiple mowing and a controlled burn). Challenges of weather (wet fields from snowmelt or rain in spring, delaying planting time, for instance), can be similar, too.

    Fields we rented 4.5 miles from our farmstead to plant oats and prairie grass were wet, very late into spring; the landowner also did not finish harvesting his corn from the previous year, well into March 2009. We chopped up the corn stalks, grass and weeds on March 30 with a 6-foot rotary mower (4 hours). We disked and planted one field to hay and oats as a nurse crop on April 12 (7 hours’ labor). I disked the field with a 9-foot implement and a JD 3020 tractor. My son Micah followed me, seeding the oats with a 9-foot drill and a small Massey Harris tractor.

    Using the same equipment and manner of ground preparation, I established a winter wheat stand in a second field the following October. Oats and wheat grain harvested from both fields were mixed with purchased organic feeds for our own livestock to cut down on feeding expenses. We have seen 300 and 400 percent increases in purchased certified organic feeds for poultry, sheep and goats over the past 10 years.

    Switch grass can be successfully planted into late spring. With the same equipment again, we mowed corn stalks and weeds in the second rented field, where we planted the switch grass, on June 5, 2009, (3.5 hours labor) and disked the field twice on the same day with the JD 3020 and hydraulic disk (2.5 hours). The specialized drill, a Truax 812 circa 1978, from the DNR quickly planted the field on June 12. Cooperating with a public program requires advance planning and scheduling around state-owned seed drill use over broad areas by multiple landowners.

    I mowed the switch grass/prairie grass field with the 6-foot JD rotary and tractor on Aug. 24 to help the grasses get established over competitive weeds and to keep weeds from going to seed. Conservationists recommend two cuttings the first season, but our farm was short-handed and time did not permit a second cutting in 2009.

    Two conservationists recommended controlled burning of the stand the following spring to enhance robust, heavy cellulose qualities in stems and to strengthen competition with weeds and other grasses. Burning is especially effective in controlling broad leaf weeds. We were not able to do this. Area prairie grass establishment enthusiasts who have the equipment and capability of conducting controlled burns were already committed. We did mow the field in 2010.

    Applied Ecological Services of Brodhead, Wis., which provided the 20 lbs. of native species switch grass seed (Panicum virgatum) for our study, was not able to harvest seed from our study’s planting before the grass went to seed in 2011. Recommended seeding rate was 5 lbs. per acre (per AES and the DNR). A good seed harvest rate is about 300 lbs. per acre.

    We went ahead Oct. 22 with our first harvest of the straw after the seed had fallen. We harvested about 240 bales from a little more than 3.5 acres, which compares well to the modest yields of straw we’ve been harvesting from our small-field oat and wheat plantings for several years.

    I cut the switch grass the day before harvest, on a warm, windy, sunny day. I raked the grass the next morning as soon as the autumn dew subsided and baled it very late afternoon, just before dark. Temperatures both days were well into the 60s F, and skies were clear. Rain was threatening in the Sunday forecast; we would surely have left the grass dry a second day had we been able to do so.

    Wild switch grass seems to dry under the conditions we experienced more quickly than hay would have. “Switchgrass is a diverse species, with striking differences between plants. This diversity, which probably reflects evolution and adaptation to new environments as the species spread across the continent, provides a range of valuable traits for breeding programs. Switchgrass has two distinct forms, or “cytotypes”: the lowland cultivars, which tend to produce more biomass, and the upland cultivars, which are generally of more northern origin, more cold-tolerant, and therefore usually preferred in northern areas.” (http://en.wikipedia.org/wiki/Panicum_virgatum )

    The native species switch grass seed, which we obtained from AES and used to establish our own switch grass field, seems to be finer, thinner than the prairie grass straw we obtained in 2008 in partnership with a neighboring fruit and vegetable crop grower. That grower established his switch grass field ahead of our SARE study.

    For the 2009 growing season in our comparison, we had about 25 bales of stored oat straw and about the same amount of stored wheat straw on hand from previous harvests. We also had nearly 300 bales of prairie grass straw in our haymow from helping this neighboring asparagus and fruit producer harvest his own straw on his property in November 2008.

    We took several loads of the prairie grass straw as compensation for helping this neighbor harvest his straw when his machinery broke down. The 2009 growing season was our first to employ prairie grass straw as a mulch for our own vegetable crops.

    Seed prices for wild-type Switch Grass (as of October 2011, per AES) range from $7 to $20 per lb., depending upon origin. It is very important to obtain seed from the same source as one expects to work with at harvest later on. That source must be in the market for the seed, of course, and have the capability of harvesting, cleaning and processing the seed for sale to a wider market. Other more common selections of switch grass seed generally fetch much less in return, $3 to $7 per lb. Cave-in-the-Rock and Blackwell are common selections.

    Applied Ecological Services and Taylor Creek Nursery and Restorations, in rural Brodhead, Wis., about 6 miles from our farmstead, has strong capability to harvest, clean, process and sell native species grass and flower seeds. Prairie grasses reseed themselves several times through a growing season. They also provide cover for pheasants and other game birds in spring and fall. They are attractive hunting grounds along tree lines and hedgerows for hunters, providing alternative and additional sources of income from a planting primarily intended for harvesting straw mulch.

    Switch grass has been researched as a bioenergy crop since the mid-1980s, and is still being considered for use in several bioenergy conversion processes, including cellulosic ethanol production, biogas, and direct combustion in pelletized form to produce thermal energy. Studies have shown that it can take less than a third as much fossil fuel to produce than equivalent yields of corn. Because it requires far few inputs and chemicals to produce, its output to input ratio as a biofuel has been put at 20 to 1. These potential uses for switch grass promise additional revenue streams in the future from mastering its production for straw mulch use today.

    Sharing Straw Mulch Comparisons

    We sent out the attached press release on the field day held at our farm to state-line and local, general circulation newspapers. We also notified growers through our state-line Collaborative Regional Alliance for Farmer Training and the Madison Area CSA Coalition. About 30 growers or organic and sustainable farm interns on mostly Community Supported Agriculture farms in southern Wisconsin and northern Illinois attended the field day.

    Our comparative use of straw mulch was shared with an annual May Tour the Farm Day (of more than 100 state-line visitors) and a workshop we hosted here on high tunnel greenhouse construction and use for the Madison Area CSA Coalition this past winter (about 20 people attended). Both UW Extension and DNR participants in our study made presentations on the straw mulch study at our field day.

    A PowerPoint on using prairie grass and small grains straw mulch to bed vegetable crops is being made from this report for a Farmers Forum presentation at the National Small Farm Trade Show & Conference in November 2011. Wisconsin State Farmer’s editor has agreed to publish an article written from results of this SARE project. The article or similar news features will be sent to a number of other general circulation and farm publications in the region.

    List of Photos

    Page 1 – Farm apprentice Trish DeCoster applies straw mulch to broccoli transplants at Scotch Hill Farm in 2010
    Page 2 – Vegetable transplants in black plastic mulch, with walking and driving paths in a rented field one mile from Scotch Hill Farm.
    Page 3 – Garlic, which was planted in 2009 and mulched with straw over winter, growing strong in spring at Scotch Hill Farm.
    Page 6 – Field trial comparison photos of small grains and prairie grass straw mulch, Figure 1
    Page 7 – Prairie grass mulch, 40 days into 2010 field trial, Figure 2
    Page 8 – Straw mulch in snow peas rows, spring 2010
    Page 9 – Straw mulch in broad cabbage bed, summer 2010
    Page 10 – Seeding prairie grass / wild switch grass in rented field in June 2009
    Page 11 – Close-up view of specialized planter for prairie grasses and native species seed, loaned to landowners from Wisconsin Department of Natural Resources
    Page 12 – Switch grass seed, loaded into drill for planting

    Public invited to Aug. 30 straw mulch field day

    Crop growers and gardeners are welcome to view prairie grass and small grains straw mulch at Scotch Hill Farm, 1 to 4 p.m., Monday, Aug. 30.

    An optional potluck meal at noon will precede the field day at the small crop and livestock farm on the Green-Rock county line north of Brodhead. Meal participants should bring a warm or cold dish to pass.

    Certified organic vegetable crop farmers Dela and Tony Ends have been comparing switch grass, wheat and oat straw mulches for two seasons. They are trying to cut reliance on rolled black plastic mulch, which they use to control weeds in thousands of transplanted bedding plants.

    UW Extension Rock County and Wisconsin Department of Natural Resources staff have been taking part in the USDA Sustainable Agriculture Research and Education farmer-rancher study. Dr. Jim Stute, an Agriculture Extension Service crops and soils educator, and Brian Benzow, DNR conservation field service staff member, will take part in the field day.

    Switch grass, oat and wheat straw are mulching several types of beans, cabbage, Brussels sprouts, sweet potato and other vegetable crop varieties at Scotch Hill Farm. The 16-year-old farm grows more than 100 vegetable varieties for several hundred families who subscribe for weekly fresh produce delivery.

    Black plastic mulch has increasingly helped vegetable crop farmers control weeds since the 1950s. By 1999, the practice had spread globally to more than 30 million acres.

    Mulches conserve soil moisture, prevent erosion, cut soil compaction and eliminate root damage deep cultivation or hoeing may cause. Their weed suppression cuts labor expenses, too.

    Extracting and disposing of plastic mulch after the growing season pose challenges for most growers, though photodegradable and biodegradable plastic mulches are being developed.

    Organic mulches contribute plant matter back to the soil, increasing soil fertility and mineral production for subsequent crops. The Scotch Hill study is comparing how readily different kinds of straw mulch break down and make nutrients available to the soil.

    Applied Ecological Services of Brodhead, which restores native species plantings, provided switch grass seed for this study. Switch grass is also drawing interest in the Upper Midwest as a bio-fuel alternative to gasoline.

    A map and driving directions to the farm and field day are available at www.scotchhillfarm.com Contact the Ends at 608 897-4288 or tony@scotchhillfarm.com

    Scotch Hill is a Madison Area Community Supported Agriculture Coalition grower and steering committee participant n the state-line Collaborative Regional Alliance for Farmer Training (CRAFT). The Aug. 30 field day is a CRAFT farm tour for interns and Farm Beginnings participants.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.