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

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

Summary

We are small-scale minority farmers. We are certified organic growing vegetables, fruits, and nuts including eggplants, cucumbers, sweet peppers, squash, tomatoes, kale, collards, sweet potatoes, cantaloupes, watermelons, strawberries, muscadines, blackberries, and pecans. These crops have been grown in combination with a no-till, drill conservation practice using organic red clover, cereal rye, and oats as cover crops. Years ago, my grandmother farmed this land. She was a great small farmer with a second grade education. She produced all kinds of wonderful vegetables, peaches, pears, walnuts, pecans, and even turkeys, ducks, and a few dairy cows for her milk and butter. This is Lola’s Organic Farm.

Objectives/Performance Targets

Our small farm faces a serious challenge which is common to many small farms that experience invasive Bermuda grass where organic vegetable production is being attempted. Often annual plowing or deep harrowing combined with mechanical cultivation fail to provide adequate suppression of this highly vigorous and invasive weed. In addition, attempting to manage invasive perennial weeds like Bermuda grass through tillage and cultivation alone can burn up soil organic matter, degrade soil quality, and increase the risk of erosion by water or wind. Because a healthy soil, rich in organic matter provides the foundation for successful organic production, organic producers need to develop practical, integrated strategies to manage stubborn weeds like Bermuda grass while conserving and improving 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.

The project involves a field study of two non-chemical strategies for managing heavy common bermuda grass infestation to prepare for organic vegetable production:  A mechanized cultivation and hand tillage strategy and biological control strategy using correctly planted and managed cover crops to suppress and control the growth of common bermuda grass. 

Objectives:
To evaluate two non-chemical strategies (multiple tillage and cover crops) to contol and manage heavy bermuda grass infestations.

Accomplishments/Milestones

Organic Buckwheat was grown late April to early June, then harrowed under, and followed by a millet/cowpea mix until late October. All three cover crops were carefully managed to give optimum benefits for shade competition and alleleopathic substances to control common bermuda grass and other weeds. Plots were developed, sized to:  1/10 acre, divided into two 1/20 acre subplots.

Each subplot measures 32’x68’ and contains twelve, 100 sq. ft. beds.

Subplot One has undergone six months of cover crop management: •including bottom plowing, harrowing, sowing to buckwheat, and watered for emergence.

Buckwheat was harrowed under, amendments applied, millet/cowpea sown.

Non-treated Millet/organic cowpea received first and second mowing and was harrowed to incorporate.

 Subplot Two has undergone eight soil cultivations over six month period including bottom plowing,  tilling,  and weeding. Each cultivation was followed by hours of weed raking and removal.  The area was tilled 6-8’ deep in both north to south and east to west directions. Weeds were removed after each of the 8 cultivations by hand cultivator and hand rake.    Major weeds encountered were Bermuda grass, crabgrass, and nutsedge.

 Comparative measurements for the two weed management strategies  (Subplot One and Two) have included: Soil – pH, mineral analysis, organic matter, microbial activity; project cooperator provided soil recommendations and strategy; weed counts & weights, etc.

 Kale and onion transplants have been grown from organic certified seed for Subplots one and Subplot Two.  Worm compost was used and gave excellent results for germination. Drip irrigation was laid out and used. Kale and onion transplants have been planted.  Amendments were applied as recommended by collaborator leader. Frost cloth row cover was used to protect from low temperatures, deer, rabbit, and pest, etc.

Impacts and Contributions/Outcomes

Lola’s Organic Farm presented this SSARE Producer Grant Project to the 2014 Georgia Organics Conference participants, on February 22, 2014. The SSARE representative Mr. B. Washington provided an overview of SARE Producer Grant Program.  Our presentation was well received, we discussed the project, what we learned this far, and important role of SARE.

The project is active and proceeding with outlined methods.

This SARE Project was developed to  help all farmers in our area who are facing the challenge of controlling  invasive weeds such as bermuda grass. These results will be important to sustainable organic farming systems and conventional farms.

Collaborators: