Multi-Species Cover Crops Control Weeds and Improve Fertility in Organic No-Till Fields

Project Overview

FNC10-837
Project Type: Farmer/Rancher
Funds awarded in 2010: $18,000.00
Projected End Date: 12/31/2012
Region: North Central
State: North Dakota
Project Coordinator:
Linda Grotberg
Prairie Farm Pilot Project

Commodities

  • Agronomic: corn, millet, oats, rapeseed, rye, spelt, sunflower, wheat, grass (misc. perennial), hay
  • Animals: bovine, poultry, goats
  • Animal Products: dairy

Practices

  • Animal Production: parasite control, animal protection and health, grazing - continuous, free-range, grazing management, livestock breeding, manure management, mineral supplements, grazing - multispecies, pasture fertility, preventive practices, range improvement, grazing - rotational, housing, stockpiled forages, stocking rate, watering systems, winter forage, feed/forage
  • Crop Production: windbreaks
  • Education and Training: decision support system, demonstration, display, farmer to farmer, focus group, mentoring, networking, on-farm/ranch research, study circle, workshop, youth education, technical assistance
  • Energy: bioenergy and biofuels, energy conservation/efficiency, energy use, solar energy
  • Farm Business Management: whole farm planning, new enterprise development, budgets/cost and returns, marketing management, agritourism
  • Natural Resources/Environment: carbon sequestration, biodiversity, habitat enhancement, indicators, soil stabilization, wetlands, wildlife
  • Pest Management: allelopathy, biological control, competition, cultural control, economic threshold, eradication, field monitoring/scouting, genetic resistance, mulches - killed, mulches - living, mating disruption, physical control, prevention, sanitation, smother crops, mulching - vegetative, weather monitoring, weed ecology
  • Production Systems: agroecosystems, holistic management, organic agriculture, permaculture, transitioning to organic, integrated crop and livestock systems
  • Soil Management: earthworms, soil analysis, composting, nutrient mineralization, soil microbiology, soil chemistry, organic matter, soil physics, soil quality/health
  • Sustainable Communities: community planning, infrastructure analysis, leadership development, local and regional food systems, partnerships, public participation, analysis of personal/family life, community services, social capital, social networks, social psychological indicators

    Summary:

    [Editor’s Note: To see this report with photos, open the PDF version of the report.]

    PROJECT BACKGROUND
    Lead Organizers: Dick and Linda Grotberg, and Dick Lovestrand, operated Bethany Prairie Farm in northwest Barnes County, North Dakota. The Grotberg’s and Dick Lovestrand were the lead organizers of The Prairie Farm Pilot Project, a group of farmers who meet together regularly to study, mentor and promote sustainable agriculture. Dick Lovestrand passed away October 5, 2011. The Grotberg’s continue to operate Bethany Prairie Farm which consists of 440 acres, 400 of which are tillable, and livestock which consists of 70 Scottish Highland Cattle, milking goats, grass-fed lambs, and pastured poultry. The farm is in the 5th year of organic conversion.

    Farmer Partners in this project are: John and Helen Olson, (11025 48th St SE, Litchville, ND 58461, Phone 701-762-4498) are 25 year integrated certified organic farmers. In the past they have used only conventional tillage, but last year they began using multi-species cover crops and some conservation tillage. Mark and Joan Gehlhar, (9464 41st St. SE, Ypsilanti, ND 58497. Ph. 701-489-3438) The Gehlhar’s operate a custom grazing operation on half of their 1,500 acres and holistic grain farming on the other half.

    The Prairie Farm Pilot Project is involved in the journey of converting small and mid-sized conventional farms to the 1950’s farming model (SARE FNC06-625) which was agriculture before the wide spread use of chemicals and basically organic. The project that followed was (SARE FNC08-738) Organic No-Till–The Ultimate Cropping System for Soil Health and Farm Sustainability. These projects were centered on the Bethany Prairie farm. The Olson farm is certified organic for over 25 years and is beginning to use cover crops and conservation tillage. The Gehlhar farm is a holistic grain farm/custom grazing operation.

    PROJECT DESCRIPTION

    GOALS: The primary goal of this project is to reduce weeds and improve fertility in organic no-till fields.
    The group’s mission is to research, learn, and make use of expert advisors to restore chemically dependent over worked soils to full health and to make the most of crop and livestock integration in sustainable production. The true mission of organic sustainability is to restore soil to health in order to grow healthy plants to feed healthy animals which produce healthy meat, milk, and eggs to provide food to sustain healthy people.

    The Prairie Farm Pilot Project is committed to achieving this by using a sustainable organic, holistic, synergistic, biodiverse farming plan and by teaching the concept to others. We believe that the plan must include multi-species cover crops.

    Bethany Prairie Farm (BPF) is a demonstration site for sustainable organic no-till farming using multi-species cover crops as a key practice. It is our hope to change the concept of cover crops as an ignored asset to the idea that they are a key to soil health – the basis of farm sustainability.

    PROCESS
    With the inclusion of Bethany Prairie’s USDA Organic EQIP and CSP contracts, the Olson’s Organic EQIP, and the Gehlhar’s EQIP and future CSP contract, the practices that we are recording became even more relevant. Organic no-till field studies to suppress weeds and increase fertility included one or more of the following treatments on each of the eleven Bethany Prairie fields as well as some being used on the other farms also:

    Crop rotations were used to include high residue producing crops at BPF where we tried to maintain 90 percent residue cover on the surface after seeding. The Gehlhars use an exclusive no-till conventional rotation. They have found that the second year soybeans follow soybeans is the most productive. The Olsons have proven the buckwheat grown on the same field the second year improves fertility. The Crop Sequence Calculator from Northern Great Plains Research Laboratory, PO Box 459, Mandan, ND 58554, Phone 701-667-3000, www.mandan.ars.usda.gov was an interactive program that we used for viewing possible organic crop rotations and calculating returns.

    Continuous organic no-till was used for all crops and cover crops planted at Bethany Prairie. Continuous conventional no-till was used at the Gehlhars. The Olsons used conservation tillage and avoided completely black soil as much as possible in an organic tillage system.

    Deep mulch that is the result of continuous no-till is increasing on the BPF fields. Second year winter rye was rolled using the Rodale roller/crimper. Only 50 percent of the cover was grazed before the herd was moved to a new field.

    A specific plan was developed with NRCS for Field # 9. This field was described by Dick Grotberg as the poorest land on the Bethany Prairie Farm. The soil quality is poor. We have had trouble getting enough mulch to cover the soil. The plan includes early heavy grazing, then planting sweet clover with a cereal grain the first year. The following year the clover will be allowed to come back and will be grazed very heavy early or roller/crimped when clover is in full bloom (not allowing seed to form). Then if hayed or grazed wait three to four weeks, then sow brassicas such as turnips and radishes. Graze very heavy for 10 days, then allow the brassicas to grow, grazing later on in the fall. If crimped, broadcast brassicas immediately afterward. Broadcast rates with the brassicas being heavy (8 to 10 lbs. per acre). If heavy with radishes it will not be expensive. In September after grazing, sow a cereal winter annual such as rye or winter wheat. Harvest then sow a cover crop mix (heavy with legumes such as peas, lentils, soybeans, etc. and include millet). Graze this in fall. Following spring start the process over again.

    Gehlhars are finding that they are able to reduce the use of chemicals because of no-till and the mulch that is created.

    Winter crops and crops with natural allopathic characteristics were used at Bethany Prairie to naturally suppress weeds. On two side-by-side fields of winter rye and winter wheat, the weed suppression, especially dandelions, was better on the rye than the wheat.

    Multi-species cover crops were used on the Prevent Plant acres and provided year long residue cover and added fertility. The challenge was to be able to keep the cover crops growing without maturing because the Prevent Plant acres could not be grazed or harvested until after November 1st. On the rest of the BPF crop acres cover crops grew continuously. Mixtures of cool or warm season species depending on the planting date were planted immediately after the crop was harvested. Companion crops such as Lentils were used with hard red spring wheat to provide nitrogen for the wheat.
    The cover crop mixes used were:
    • Peas 10#, oats 10#, lentils 5#, radish 2#, turnip 2#
    • Radish 5#, turnip 5#, lentils 20#
    • Radish 2#, turnip 2#, lentils 10#
    • Cow peas 10#, sudan grass 10#, sweet clover 2#, sunn hemp 10#, soybeans 10#

    Gehlhars were only able to plant cover crops after the spring wheat was combined as corn and soybeans were harvested too late to plant cover crops. Jack Olson uses multi-species cover crops mainly to provide, cover over winter and green manure for the organic rotation.

    Mob grazing: The cows were turned into the field immediately before or after planting grain or cover crops to graze down the growing weeds and provide nutrient cycling on location.

    Termination of cover crops using non-chemical methods was a challenge for BPF. We discontinued using the flail mower, because it chopped so fine and close to the ground that instead of creating mulch, it seemed to destroy it. Flailing also closed the thistle stem rather than leaving it open and vunerable to rain. A swather was retrofitted for clipping by removing the platform. The plants were then cut higher off the ground and spread evenly. The roller crimper was used in several applications that worked well on winter rye and triticale. This coming year we will use it on sweet clover. Frost kill worked for other growing cover crops and the cows grazed the residue over winter.

    Clipping weeds such as Canadian thistle and wild mustard in growing grain and cover crops with a CRP style cutter instead of flail mowing or grazing was the most successful on the Prevent Plant fields.

    Spreading chaff and chopping straw with the combine to provide an even soil covering, was used when combining the winter wheat, and that was the only grain harvested at Bethany Prairie.

    PEOPLE
    • Carol Peterson, Regional Coordinator, USDA Resource, Conservation and Development program, in cooperation with the local Sheyenne James RC and D Council. Ph.701-252-2521. Carol helped with grant resources and technology contacts.
    • Steve Zwinger, Agronomy Research Specialist, NDSU and Ron Wiederholt, Nutrient Management Specialist, Carrington Research Extension Center, 633 Hwy.281 North, Carrington, ND, Ph. 701-.652-2951. Steve provided research and expertise with organic no-till and with the roller/crimper. Ron provided advice and mentored the carbon sequestering portion of the project
    • Paul DuBourt, District Conservationist, USDA-NRCS, 805 Lenham Ave, Cooperstown ND 58425. Ph 701-797-2240. Paul was the advisor for the involvement in the USDA Organic EQIP and the CSP programs.
    • Gene Goven, holistic grazer and no-till grain farmer, (Turtle Lake, ND, Ph 701-720-7792), and Gabe Brown, holistic no-till farmer innovator, (3752 106th St NE Bismarck, ND 58503, Ph 701-222-8602) mentored the cocktail mix cover crops, holistic no-till, and grazing aspects of the project.
    • Ken Miller, holistic grazer, no-till grain farmer, and District Technician for the Burleigh County Soil Conservation District, (1511 E Interstate Ave, Bismarck, ND 58503, 701-663-9350)
    • Paul Overby, (Value Added Mgmt Solutions, 5237 78th St, Wolford, ND 58385, Ph 701-656-3654) Paul provided training for Farm Works software and GPS monitoring.
    • Soil Science Team Susan Samson-Liebig, Soil Quality Specialist, USDA-NRCS, Bismarck, ND, Fred Aziz, Area Soil Scientist Area II, USDA-NRCS, Jamestown, ND, Lance Duey, Soil Scientist, MLRA 55 A & B, Devils Lake, ND, Kris Nichols, Soil Microbiologist, USDA-ARS, Mandan, ND, Advisors: Mark Liebig, Soil Scientist, USDA-ARS, Mandan, ND, and Dick and Linda Grotberg.

    RESULTS
    Weather was the extreme challenge of 2011.

    • The long winter was the second in a row with cold temperatures and large amounts of snow. Grazing in the fields was terminated with the first blizzard in November 2010, bale grazing in the field was terminated in December, and by January 2011 we were bulldozing snow to have a feeding area. The roof of our two large pole barns collapsed under the weight of snow, animals were lost both in the barns and outside due to the weather.

    • What a difference a year made! The first snow in the 2011/2012 winter didn’t come until long after Christmas. The cattle grazed the pastures and cover crops all winter!

    • Spring and summer 2011 were extremely wet, hot and muggy! Everyone’s HRSW suffered with poor yields due to disease. Most of the Bethany Prairie Fields were either Prevent Plant or planted to cover crops and used for grazing. This was beneficial to our bottom line and provided so much extra feed for the livestock, both above and below the ground, that we did not need to start grazing the pastures until late in September. We were able to bale all of the hay that was needed for BPF and enough for Mark Gehlhar to replace the hay from his wet acres.

    The GPS and Farm Works Software were used to flag inspection sites in BPF fields where soil samples were taken by Justin Vogel and tested at Agvise Laboratories in the spring and fall for N,P,K, organic matter, sulfur, zinc, magnesium, calcium, sodium, soluble salts, soil pH, total organic carbon, nitrogen mineralization, and bulk density. The hoped for result, an increase in N, has not yet been realized. However the soil biology is improving. During the growing season samples were taken for microscope examination of microbial activity.

    The Soil Science Team (see PEOPLE) continued to monitor the soil health below the surface with an annual planning meeting at Bethany Prairie and yearly site visit for taking soil samples. The Spring of 2011 complete soil food web analysis was postponed on original test sites due to the extremely wet conditions, however, “The soil study will increase understanding regarding the current state of soil quality in North Dakota as well as a baseline for a system converting from conventional agriculture to organic. Additionally, data collected during the course of the study will help in understanding carbon sequestration potential and nutrient movement under organic no-till, conventional tillage, and grazed pastureland and cropland, thereby expanding the knowledge base regarding the environmental sustainability of each management system. Evaluation sites will be used to demonstrate benefits of conservation-oriented management practices on soil quality, carbon sequestration, and agricultural productivity”. -Susan Samson-Liebig, Soil Quality Specialist, USDA-NRCS

    As the cattle moved through the cropping and pasture system for grazing, fecal samples were sent in for laboratory analysis. NUTBAL PRO software was used to determine the value of grazed forage. The most recent fecal sample was collected this February, while the cows were still grazing in the fields before they began eating bales. The NUTBAL analysis showed adequate nutrition.

    Economic Impact – Input costs are definitely decreased in a no-till farming system. On a farm using petroleum diesel fuel this is a large input that is favorably reduced. At BPF we were not able to put as many hours as we wanted to on the 2290 Case tractor using our homemade vegetable oil fuel because of the decreased trips over the field. As we compare our numbers with those of ND Farm Business Management, NDSU and USDA, so far we are behind – the organic no-till grain crops do not show a profit. We are improving soil health and ultimately hope that our bottom line improves as we use multi-species cover crops to improve soil fertility and weed and pest control. The USDA Organic EQIP and CSP programs have had an especially large impact on making the transition from conventional agriculture to no-till organic farming. Without them we would not have been able to make the transition and have an economically viable farming operation.

    Environmental Impact – Soil health is improved as determined by a broad spectrum of soil testing. An increase in carbon sequestration was recorded by the scientists involved in the project. Fields do have less or at least different kinds of weed pressure. Mark Gehlhar is concerned that 2012 will show new varieties of weeds in soils that are being reclaimed after so many wet years. The soil is about 75 percent covered year around. Our farms are home to many kinds of plants, diversity in experimentation, and multi-species cover crops as we transition into sustainable, conservation, or organic no-till agriculture.

    Social Impact – The Prairie Farm Pilot Project experiences and practices are documented and recorded. We have become a role model pilot project for responsible, sustainable, organic no-till agriculture, in our region. The Project’s farmers have positive experiences to report. Family farm core values are enhanced and sustained. We are able to satisfy human food and our livestock needs. Quality of life is enhanced for farmers and society as a whole. Encouraging feedback received from the 200 friends and neighbors who attended Dick Lovestrand’s funeral was both humbling and inspiring.

    One of the dreams of this project has been to find new families who want to raise sustainable family friendly food on farms that are multifunctional, a polyculture producing not only quality food, but also contributing to a community’s overall economic and social development. Our dream farmer this year is a large farmer, Robert Joos, Wimbledon. Robert has determined to raise crops and livestock without using chemicals, and to transition his farm to sustainable organic.

    DISCUSSION
    The Olsons are progressing toward a more sustainable farming system through the increased use of conservation tillage and multi-species cover crops.

    The Gehlhars are progressing toward a more sustainable farming system through the continued use of no-till, multi-species cover crops, and grazing.

    At Bethany Prairie Farm we are progressing very very slowly at being sustainable in no-till organic crop and livestock farming. The combination of no-till and organic is at best a challenge and at worst a failure that only the cattle can redeem. As our soil continues to prosper, we believe that our bottom line will prosper as well.

    Our learning experience at BPF and in the Prairie Farm Pilot Project is best described by the late Dick Lovestrand, “After the hog operation met its orderly demise, we began to ask questions about health and nutrition. We read, read, read about the other side of agriculture. The side of agriculture where the growing medium (Soil) is high on the priority list. We read about health, sickness, and disease.

    “Some of our reading took us into the classics of health. Our parents could have read the authors who have opened our eyes to the pathetic health and nutritional quicksand we have walked into.

    “Some of our reading showed us that true health is a triangle whose sides are thinking right, living right, and eating right. Concentrating on just one side – say, eating right does not ensure health. Positive thinking alone does not ensure health if we neglect proper foods and right attitudes in living.
    “We have come to understand that if, indeed God made us from the dust of the ground, then the food that we eat needs to come from healthy vibrant soil; soil that will produce food that the body will recognize.

    “Rebuilding soil that will sustain healthy vegetation for grazing animals is not a quick process. We have come to understand that natural fertilizer (animal manure and green manure) is a must for healthy soil.

    “There are many books on the need for healthy soil, many more on the need for healthy foods. From what we have heard and read, we are convinced that the same soil from which humanity was made cries out to us for our respect. The soil says to us, treat me right and I’ll provide you with an abundance of living food.”

    In the spring of 2007 we decided to sell 160 acres of land that was not immediately connected to the rest of Bethany Prairie Farm in order to clear the debt on the farm. This left 440 acres to farm naturally that we might be able to farm in such a way as to be a true pilot project.

    We needed to be able to show by example that farming naturally is an option for every farmer who has the heart for it. With that in mind we record our ideas, impressions, facts, and circumstances.

    OUTREACH
    See Brochure and flyer attached.

    • Prairie Farm Pilot Project Field Day and Bethany Prairie Farm Tour June 28, 2011
    The Prairie Farm Pilot Project Field Day and Bethany Prairie Farm Tour was held June 28, 2011 at the Bethany Prairie Farm rural Wimbledon, ND. The Prairie Farm Pilot Project is an ongoing experiment in the process of Bethany Prairie Farm’s journey toward sustainability. The Prairie Farm Pilot Project focuses on healthy soil being the basis of healthy food and healthy people. The Project is currently involved in growing and producing biofuel, soil nutrients, weed control, energy, and food on the farm.

    The registered attendance was 47 and included farmers/ranchers, NRCS staff, city dwellers, Carrington Research Extension personal, and media representatives.

    • This year’s Field Day was a showcase for Prairie Farm Pilot Project’s “Multi-Species Cover Crops Control Weeds and Improve Fertility in Organic No-Till Fields” NCR-SARE Farmer/Rancher Grants.
    The workshops and tours in the fields had to be cancelled due to wet conditions and muddy roads. Presentations were given at the Big House by Fred Aziz and Hal Weiser, Area Resource Soil Scientists, NRCS; Steve Zwinger, Collaborator in the Rodale Institute Organic No-Till Project and Research Specialist-Agronomy, North Dakota State University, Carrington Research Extension Center; and Paul DuBourt, District Conservationist, Griggs County NRCS, Cooperstown. Linda Grotberg told of Bethany Prairie’s long range plans to build healthy soil to be able to grow healthy food.

    Dick Lovestrand, Bethany Prairie Farm and Paul Aakre, UMC  conducted an oil press demonstration and answered questions concerning Bethany Prairie’s future plans and uses for the small scale renewable fuels.
    The Rainfall Simulator demonstration was presented by Jeff Hemenway, Conservation Agronomist SD NRCS State Office, Huron, SD

    Approximately 55 Scottish Highland roast beef dinners with all local food trimmings were served at noon by Bethany Prairie Fellowship. Midwest Dairy Dist #5 served soft serve ice cream for dessert.

    Advertising included announcements in the NPSAS Germinator and The Wimbledon News, a feature story in the Valley City Times Record, state, regional, local email list serves, mailed personal invitations, flyers posted in USDA offices, Extension and local businesses, and word of mouth.

    Wimbledon Newsletter, August 3, 2011, Wimbledon ND
    “Encore Farmers” and Sustainable Agriculture Pioneers
    There is always something new happening at Bethany Prairie Farm. Linda Grotberg, her husband Dick and farming partner Dick Lovestrand operate their 400-acre farm southeast of Wimbledon as a sustainable farming research station. They have left behind traditional hog farming in their search for healthier options for themselves as well as the farm’s soil. They became organic, no-till farmers. “I love the proverb, ‘dig your well before you’re thirsty’,” says Linda. “That’s my philosophy with sustainable agriculture. We have to keep experimenting and innovating, so we know how to do it before we have to do it.”
    Bethany Prairie Farm is operated by (left to right) Dick Lovestrand (68 years old), Linda Grotberg (66), and Dick Grotberg (75)
    They are very willing to share their hard gained knowledge, holding an annual open house field day each summer. Their free-range chickens, Scottish highland cattle, and dairy goats provide food for themselves and a source of farm income.
    This spring, Linda Grotberg was one of five finalists in the Launch Pad contest, created to encourage “purpose-filled” careers in the second half of life” by the organization Encore. Her project, to make small farms sustainable by helping local farmers make homegrown fuel using strait sunflower oil, won a $5,000 prize. Paul Aakre, presently assistant professor of mechanized agriculture at the University of Minnesota – Crookston, has been a collaborator with Bethany Prairie on the sunflower biofuel project since his days as an NDSU graduate student. They are working together to evaluate the constraints of a family farm operation to produce its’ own fuel.
    Winning the Launch Pad contest brought media attention. Most recently, journalist Jonathan Knutson of Forum Communications and Agweek wrote an extensive piece about the innovations taking place at Bethany Prairie. It was featured in the June 27 issue of Agweek and appeared as a full page in the July 4 Fargo Forum. Daily newspapers in Minot, Grand Forks, and Bismarck carried it. “That article has gone around the world,” Linda said. “Reuters picked it up. I googled my name, and there were 14 pages of responses, all tracing back to Knutson’s article.” Quite a global impact for a small farm on the North Dakota prairie. – Mary Beth Olombel, Editor

    The following are some of the internet sites mentioned in the Wimbledon Newsletter article:
    They’re ‘encore farmers’
    www.agweek.com/event/article/id/18640/
    Jun 27, 2011 – WIMBLEDON, N.D. — Linda Grotberg says she and her two partners in Bethany Prairie Farm in Wimbledon, N.D., are “encore farmers.

    June 30, 2011 – MultiBriefs
    multibriefs.com/briefs/SWCS/SWCS063011.php
    Linda Grotberg describes herself, husband and their friend as “senior citizen … that is designed to improve soil health at their farm in Wimbledon, N.D. More …

    Civic Ventures Names Winners of $5K LaunchPad Project Awards …
    www.secondact.com/…/civic-ventures-names-winners-of-5k-launchp…
    Mar 2, 2011 – Linda Grotberg, 66, of Wimbledon, N.D., a retiree turned organic, no-till farmer who plans to expand her work with small farmers and rural …

    Producing fuel from sunflower oil an award winning idea – Farm and …
    www.farmandranchguide.com/…/article_dec193a8-7210-11e0-aa25-…
    Apr 28, 2011 – WIMBLEDON, N.D. – When Linda Grotberg heard about the Civic Ventures’ Launch Pad Contest, she knew she had a perfect entry

    sustainability
    www.agweek.com/event/search/start_row/61/searchrange/…/date/
    They’re ‘encore farmers’ WIMBLEDON, N.D. — Linda Grotberg says she and her two partners in Bethany Prairie Farm in Wimbledon, N.D., are “encore farmers.

    ND Farm Operators Stress Sustainability | aromatherapyguides.org
    www.aromatherapyguides.org/nd-farm-operators-stress-sustainability/
    Jul 4, 2011 – WIMBLEDON, N.D. (AP) Linda Grotberg says she and her dual partners in Bethany Prairie Farm in Wimbledon, N.D., are “encore farmers.” …

    Linda Grotberg 02-25-11 – podOmatic
    jamied.podomatic.com/player/web/2011-02-28T12_45_22-08_00
    Wimbledon, ND resident working to make small farms sustainable by helping local farmers make homegrown fuel using straight … Linda Grotberg 02-25-11 …

    ag right | Page 6
    agright.areavoices.com/page/6/
    Jun 21, 2011 – The operators of Bethany Prairie Farm near Wimbledon, N.D., have an … Linda Grotberg, her husband Dick, and their friend and partner Dick …

    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.