Mechanical approaches to perennial weed suppression in organically established no-till cover crops

Project Overview

Project Type: Farmer
Funds awarded in 2012: $8,879.00
Projected End Date: 12/31/2014
Region: Northeast
State: New Hampshire
Project Leader:
Dorn Cox
Westwick Farming LLC

Annual Reports


  • Agronomic: corn, soybeans, sunflower


  • Crop Production: conservation tillage
  • Education and Training: demonstration, on-farm/ranch research, workshop
  • Natural Resources/Environment: carbon sequestration
  • Pest Management: biological control, cultural control, mulches - killed, mulches - living, physical control, smother crops, mulching - vegetative
  • Soil Management: green manures, organic matter

    Proposal summary:

    This project builds on organic no-till, by developing a technique to suppress perennial weed growth mechanically to improve the success of organic no-till systems. Success would enable greatly improve performance of new crops directly into sod, and crops plated through rolled mulch without disturbing the soil profile. This project provides a more in-depth follow-up to work done under a 2010 SARE grant that demonstrated the establishment of no-till vetch into hay sod. This project also builds on the observations recorded during that project and use a modified yeoman’s Keyline plow with weed knives both pre and post planting to suppress the perennial sod and weed competition.

    The 2011 SARE farmer grower grant showed the potential for no-till Establishment of hairy vetch directly into haysod. The annual covercrop is established for the purpose of roller crimping the following season to provide a weed suppressing, and water retaining mulch as well as to provide a portion of the nitrogen needs for no-till corn and or sunflowers. However, if the cover is not heavy enough when rolled down as a mulch, the perennial grasses are able to retain enough energy to grow through sections and render the mulch much less effective. This results in heavy mid season competition for the primary crop, and because the mulch is already in place traditional cultivation techniques are not possible. This project proposes to use a yeoman’s plow with large and adjustable swept undercut bars fitted with a heavy coulter to test two main approaches. The first approach is to set the undercut bar just below the top sod root layer to further weaken or kill the sod before organic no-till drilling of spring and winter covercrops, and later no till planting of corn, sunflowers, and soybeans. The second approach is to set the coulter to make one slice through the rolled mulch layer and undercut perennial weeds just below the mulch while leaving the mulch layer largely in place. This project will trial several dates, sod and mulch conditions and different depths and plow/cultivator setups.

    The primary means of outreach will be in extension organized twilight meetings in the same pattern as other research projects I have been involved in with UNH. The first meeting will take place when the vetch is planted, and will feature the planting equipment and discussion about the importance of soil health, amendments and varieties. This meeting will travel to the various test plot locations.

    The second meeting will be organized around harvest or when crimping would normally be done, but not necessarily on the actual data collection date due to the difficulty with timing optimal data collection and crimping date with publicity. This meeting will likely take place in early June.

    Target audience: Farmers from NH, ME and VT (and nearby regions) that are interested the potential for organic no-till on their farm, community members, extension professionals, and legislators that are interested in the energy and environmental benefits that this technology potentially represents.

    Publicity for twilight meetings will be from several sources:
    UNH Coopertive Extension
    Strafford, Merrimack and Rockingham, County Conservation Districts
    NH Department of Agriculture – Market Bulletin
    UNH articles

    Project objectives from proposal:

    It is clear, based on our experience that the success of organic no-till techniques are highly dependent on generating enough biomass from the covercrop. However, We have observed on our farm, and other local farms that even in the best covercrop stand has gaps when it is rolled, and organic no-tilled covercrops into hay sod often have perennial grasses as the primary weed. The intention of this project is increase the success rate of organic no-till practices and therefore increasing the adoption, effectiveness and geographic reach of the practices in New Hampshire.

    For this project there will be at least eight treatments that test timing and pre-treatments of hay sod prior to no-till planting large seeded competitive row crops including corn, soybeans, and sunflowers, and pre treatment before seeding spring and winter grains and cover-crops, including spring wheat, and a mid summer planting of sorghum Sudan grass. Each trial will include a control strip of keyline plow with weeder knives set to split the sod root layer, followed by strips with each set of seedings. Dates for large seeded crops will be last week in May to first week in June. Spring grain trials will be the first week in April, and winter grain trials will be last week in August to first week in September. The second portion of the trial with the key line plow modified as an under mulch cultivator will be conducted in the last weeks of June and first few weeks of July before plant growth prevents further passes.

    There will be four primary stages in the project –
    Stage 1) Planning and procurement of appropriate varieties and amendments
    Stage 2) Plot layout, planting and treatments
    Stage 3) Observation and data collection
    Stage 4) Analysis reporting and outreach
    Stage one: Planning and procurement of appropriate varieties and amendments

    Stage one will involve coordination with the our extension technical adviser and and contact with agronomists at Kings Agri Seeds, NRCS and Cornell Soil Health lab.

    Stage 2) Plot layout, planting and treatments and equipment demonstration workshops

    In this stage the plots will be measured and flagged This stage also involves setting up the equipment for planting. The hay fields will be mowed prior to planting to remove the bulk of the above ground biomass. The first physical process will then be to physically stress the sod by repeated mowing, as was done in the previous no-till establishment of hairy vetch. This stage also involves alerting cooperative extension and the conservation districts and posting the workshop dates with the NH department of Agriculture. (See attachment for plot layout)

    Stage 3) Observation and Data collection

    This stage will involve taking samples from control and treatment plots and recording difference in both primary crop growth and sod and weed biomass, which will be collected by hand. This stage also involves hosting twilight meetings also promoted through UNH extension, the County Conservation District and the Department of Agriculture.

    Stage 4) Analysis reporting and outreach

    June - August

    In this final stage the data will be tabulated and organized along with photos to develop posters and literature that can be disseminated to other farmers through Conservation Districts, Cooperative Extension, NRCS and agricultural web sites and publications such as the NH Farm Bureau Communicator and GreenStart’s web site, which will have capacity to publish research projects as short slide shows.

    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.