Mechanical and biological strategies to remove invasive Bermuda grass in preparation for organic vegetable production on raised beds

Final Report for FS13-267

Project Type: Farmer/Rancher
Funds awarded in 2013: $9,560.00
Projected End Date: 12/31/2015
Region: Southern
State: Georgia
Principal Investigator:
Jennifer Taylor
Lola's Organic Farm
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Project Information


We are small-scale minority farmers. We are certified organic, growing vegetables, fruits, and nuts including heirloom eggplants, cucumbers, sweet peppers, summer squash, tomatoes, heirloom greens, turnips, kale, collards, sweet potatoes, cantaloupes, watermelons, strawberries, muscadines, blackberries, and pecans. Years ago, my grandmother farmed this land. She was a great small farmer with a second grade education. She grew all kinds of wonderful vegetables, fruits and nuts, including peaches, pears, walnuts, pecans, and also turkeys, ducks, and a few dairy cows for her milk and butter. This is Lola's Organic Farm.

We, like many other farmers, face serious challenges when trying to grow vegetables in soil infested with invasive weeds such as common Bermuda grass. This challenge becomes more critical on organic farms that have different tools in their organic toolkit. Generally, invasive weeds are managed by plowing and cultivation. Excessive tillage can burn up soil organic matter, degrade soil structure, increase erosion, and reduce soil biological health. Organic and sustainable agriculture producers need to examine alternative integrated strategies as possible tools to manage serious perennial weeds like Bermuda grass while observing strategies that also work together to improve precious soil life and soil quality. The results of this study are important to all sustainable agriculture farmers facing the challenge of using organic tools on perennial invasive weeds.?

Our Southern SARE project involved a field study of two non-chemical strategies for managing heavy common Bermuda grass infestation to prepare for organic vegetable production. To implement the project we established a mechanized cultivation and hand tillage strategy plot and a biological control strategy plot using cover crops to suppress and control the growth of common Bermuda grass while examining the impact on yield.  

The SSARE Producer Grant project gave valuable opportunities and initial information on which we can build our farm operation and determine the next set of experimental tactics and strategies.



Farmers using sustainable agriculture and organic farming systems use different farm practices than most conventional farming systems. Organic sustainable farmers often desire to implement management strategies that support building healthy soils and microbial activity while increasing yield. Conventional agricultural strategies prior to the use of herbicides, accomplished some degree of weed suppression by taking the land out of production for a year, using plowing in the spring followed by monthly deep harrowing in the hot months of summer as well as the coldest months of winter. Some trials have indicated considerable success on plowed Bermuda grass land by using monthly passes with a peanut digger combined with monthly raking of the grass residues during the summer months. Other studies have shown that vigorous weeds can be suppressed by using integrated intensive cover crop management strategies. Fast-growing cover crops are known for their ability to suppress weeds during short fallow periods in the summer. These reduce weed growth mainly by rapidly forming a heavy shading canopy; research with buckwheat has also demonstrated some allelopathic effect (substances released from the plant that slow the growth of other plants, including weeds). Cover crops that produce heavy biomass formation also assist with weed suppression through both competition and allelopathy, for example sorghum and millet. Although allelopathic effects are most effective against small seedlings, such as newly-emerging pigweed, lambs quarters, and other small-seeded summer annuals, the allelopathic substances in sorghums have also demonstrated significant activity against invasive perennial weeds like nutsedges.

This SSARE Producer Grant Project provided a comparison on organic farmland between two methods, a mechanical multiple tillage method and a managed biological intensive cover crop method used to suppress and control the growth of invasive Bermuda grass while observing impact on yield.  ??A combination of mechanical and biological practices, including competitive cover crops and optimizing conditions for the production crop, is needed to bring a Bermuda grass infestation under control to permit economically viable production of vegetables and fruit.

Project Objectives:

To evaluate two non-chemical strategies (multiple tillage and cover crops) to control and manage heavy Bermuda grass infestations.

To consider which method or combination of methods is most beneficial and successful with managing and controlling perennial invasive weeds- while protecting soil life/soil quality and enhancing yields.



Click linked name(s) to expand/collapse or show everyone's info
  • Donn Cooper
  • Ron Gilmore
  • Dr. Carroll Johnson
  • Jerald Larson
  • Dr. Mark Schonbeck


Materials and methods:

Our methods are reported in the SSARE Producer Grant Proposal and in the attached documents.

Research results and discussion:

Generally, The biological methods intensive cover crop management over two growing seasons gave higher onion and kale yields, however, was slower to totally suppress Bermuda grass and allowed nutsedge to increase. The mechanical management method suppressed both of these weeds effectively and much quicker. The negative responses were poor suppression of annual weeds and lower vegetable yields, lower soil moisture, etc.

As sustainable ag organic farmers one of our primary interests is to suppress perennial invasive weeds while using methods that protect and improve soil quality and soil life. Therefore as we proceeded with this study, we needed to always keep in mind the impact on soil quality and soil life - an important resource for sustainable agriculture farmers.

The producers learned the following from the SSARE Project: that it is important to have cover crop borders to suppress weeds. The cover crop intensive management strategy seemed to build healthy soil while suppressing weeds and increase cash crop yields. While the mechanical multiple tillage strategy seemed to remove weeds but reduce soil health benefits AND decreases cash crop yields.

Additional impacts are reported in the Lola's Organic Farm SSARE files below.

Participation Summary

Educational & Outreach Activities

Participation Summary:

Project Outcomes

Project outcomes:

(2016) Lola’s Organic Farm has been asked to present/participate and report project results/what was learned during the upcoming 2016 SSAWG Conference, Lexington, KY.

(2015) Producer participated in a blog interview with The National Sustainable Agriculture Coalition (NSAC).

June 2015 Lola’s Organic Farm – SSARE Organic Farm Field Day Workshop.
We held our end of project field day in June 2015. The learning session was free for all farmers, beginning farmers and ranchers, community gardeners, and organic farmers interested in sustainable organic farming systems.

Lola’s Organic Field Day provided history of our small farm, information about organic farm systems, a report of our SSARE Producer Grant Project at the farm and impact of biological methods, growing cover crops, and mechanical methods, multiple tillage, to manage weeds and build healthy soils; understanding allelopathy effects of cover crops; evaluating soil and plant tissue; hands-on pruning and grafting practices, initiatives to build sustainable farm conservation practices such as the NRCS-EQIP organic and high tunnel practices; QCS provided organic certification how-to for beginning or transitioning farmers; and SARE Producer grants program. Demonstrations included hands-on pruning, vermiculture towers and tour of High tunnel management. Handouts were provided.

Our speakers included: Lola’s Organic Farm Producers Ronald Gilmore and Jennifer Taylor, Dr. Mark Schonbeck, Virginia Association for Biological Farming; Jerald Larson, retired, Fort Valley State University; Southern SARE, Ms. C. Pollock; Georgia Organics; Quality Certification Services; and the Natural Resources Conservation Service (NRCS). Participants learned about the SSARE Project, discussed information and application to their farm or garden.

Lola’s Organic Farm SSARE June 2014 field day
was provided to public:

June 2014, on-farm learning opportunities at Lola’s Organic Farm provided information and hands-on training.  
Generally, in our area of Georgia, folks do not know much about organic farming systems - our workshop demonstrations, discussions provided important learning and networking opportunities for Georgia Organics, NRCS and SSARE- identifying opportunities for assistance to small, minority farmers, beginning farmers and gardeners interested in improving farm enterprises and learning more about organic sustainable agriculture. Farmers learned about organic farming and the impact of our SSARE project and relevance to local farm operations.


  • June 2014 Lola’s Organic Field day Workshop provided information and demonstrations about biological and mechanical weed control strategies for invasive weeds/SARE Funded Project, benefits of high tunnel operations and techniques used to meet organic certification standards. NRCS representative addressed the NRCS High Tunnel and other EQIP Organic-Initiatives beneficial to new beginning farmers, seasoned farmer/urban farm communities; Demonstrations included establishing native pollinator habitats, grafting and pruning, and controlling invasive weeds.
  • The SSARE Producer Grant project at 2014 Lola’s Organic Farm Field Day provided the basis for group examination of different weed management strategies and benefits to an organic sustainable agriculture system.   About seventy people came to the workshop. The participants included rural and urban farmers, locals and consumers. Participants were able to learn from hands-on demonstrations and discussions.
  • The June 2014 Lola’s Organic Farm Field Day collaborators included: NRCS Regional Director and NRCS-Wheeler County Office (Ms. V. Jackson and L. Woodard, respectively), Georgia Organics (D. Cooper), Fort Valley University (Retired Extensionist/Jerry Larson,) Longwood Plantation (Karen and Mike Smith), and Lola’s Organic Farm SSARE Project Producers Ron Gilmore and Jennifer Taylor.

June 2014 Registration information:

June 2014 Lola’s Organic Farm field day - DISTRIBUTION of information:

November 2014, we were presenter participants in the Southeast Georgia Growing Local and Sustainable Conference in Reidsville, Georgia. Our topic, “Non-Toxic Farming”/SSARE Producer Grant (Mechanical and biological strategies to remove invasive common Bermuda grass in preparation for organic vegetable production on raised beds) - we provided information about SARE project team, objectives, project’s successes, benefits to sustainable ag farmers, what we have learned & discussion.

February 2014, we were presenter participants in the Georgia Organics Conference, Jekyll Island, Georgia.  
We presented our Southern SARE Producer Grant Project during the Georgia Organic Conference.

  • We shared our farm challenges and anticipated on-farm impacts with farmers and community gardener participants having a similar desire to use organic farming strategies/sustainable ag strategies to control perennial invasive weeds while improving soil benefits and yields.

Overview of Accomplishments:
 The SSARE Producer Grant Project was successfully completed. The 2014-year had extremes in climate (more rain and cold weather) than anticipated which impacted project scheduling and plant growth. 

After review of the weed control progress, the producers decided to run two seasons back to back of intensive cover crops during the second year (buckwheat and pearl millet, followed in the fall by iron clay peas and millet) because we could see the benefit to the soil and we saw a success in the control and management of Bermuda grass. The weeds that followed the reduction in Bermuda grass were crabgrass and nutsedge: intensive cover cropping using iron clay peas and millet were grown to control these weeds setting up the back to back cover crop strategy in SARE-1 during year two.

As a result: Both the SARE-1 biological (intensive cover crops, limited tillage) and SARE-2 mechanical (intensive tillage) successfully reduced common Bermuda grass by more than 90%, though the biological approach took about 16 months to do so, while mechanical had achieved it within the first year. This reduction was sufficient to allow production, at least for cool season crops – strawberry, onion, and kale. Repeated tillage of SARE-2 drastically reduced the yellow nutsedge.

The producers’ examination of the cover crop management field suggested that an increase in soil moisture, soil organic matter content and crop vitality. SARE-1 plot yielded, on average, more than twice as much kale as SARE-2 suggesting a cover crop benefit to the vegetable, and perhaps improved N availability from all the cowpea biomass generated. We could see the benefit of using intensive cover crop mixes in our crop rotation plan.

Generally, organic farming with intensive cover crop management strategy seemed to build healthy soil while suppressing weeds and increased crop yields. The organic management with mechanical strategy of light multiple tillage seemed to remove weeds but reduced soil health and decreased vegetable crop yield.

How we see it: We would like to assume a long term gain through intensive cover crop management that would support soil life, active organic matter, stable organic matter (humus), overall soil health and soil quality, etc. –but this can not be fully determined over the course of a two year project. However we gained some sense of less soil stress and soil improvement due to intensive cover crop strategies and organic farming practices. An integration of the approach may provide better results.

It is very important to put together a team of project cooperators who see the “vision” and work well together. We would like to thank all of our cooperators, and a special thanks to Mr. Jerald Larson,  Dr. Mark Schonbeck, and Mr. Donn Cooper.




Potential Contributions

We are putting into practice on our farm what we have learned from the SSARE Project.

We would suggest that there is a benefit to using intensive cover crop management between cash crop rotations in our organic farm system.

The SSARE Producer Grant Project provided an opportunity to demonstrate and discuss alternative sustainable ag methods; especially important is the use of cover crops within our sustainable organic system.

The SSARE Producer Grant Project provided an opportunity to encourage sustainable ag farmers and demonstrate the benefits of SSARE Producer Grants through our farm presentations to hundreds of participants, the NSAC’s national blog; and to local farmers/producers and consumers throughout the region. Thank you SSARE.

Future Recommendations

Each year the sustainable ag farmer needs to extend the cover cropping area around the cash crops to manage invasive weed growth successfully.  

In addition to your cash crop rotations include cover crop planting to increase soil health and replenish soil with nutrients that are removed by cash crops.

Consider growing intensive cover crops as cash crops for the added benefit of improving soil function and reducing weed pressure.

We suggest that there is a benefit to using intensive cover crop management strategies between cash crop rotations on our organic farm system.


This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, through the Southern Sustainable Agriculture Research and Education program under subaward number FS13-267. USDA is an equal opportunity employer and service provider. 




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.