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

Project Overview

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

Annual Reports

Commodities

  • Agronomic: millet
  • Vegetables: onions, peas (culinary)

Practices

  • Crop Production: crop rotation, cover crops, irrigation, organic fertilizers
  • Education and Training: demonstration, extension, on-farm/ranch research, technical assistance
  • Farm Business Management: marketing management, agricultural finance
  • Pest Management: allelopathy, biological control, row covers (for pests)
  • Production Systems: agroecosystems, organic agriculture, transitioning to organic
  • Soil Management: earthworms, organic matter, soil analysis, soil microbiology, soil quality/health
  • Sustainable Communities: infrastructure analysis, partnerships

    Summary:

    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.

     

    Introduction

    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.

     

    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.