Mulching methods for weed control in a certified organic production system

Authors: Webber Iii, Charles; Davis, Angela; SHREFLER, JAMES - Oklahoma Agriculture Experiment Station

Submitted to: Annual Weed Control Research Reports
Publication Type: Experiment Station
Publication Acceptance Date: 3/1/2011
Publication Date: 4/21/2011
Citation: Webber III, C.L., Davis, A.R., Shrefler, J.W. 2011. Mulching methods for weed control in a certified organic production system. Oklahoma State University, Division of Agricultural Sciences and Natural Resources, Department of Horticulture and Landscape Architecture. Stillwater, Oklahoma. MP-162 p. 17-19.

Interpretive Summary: The weed control challenges for horticulture production are formidable; however, these challenges are even greater for those considering organic crop production. Reducing weed competition is a critical step in organic cropping systems. Use of black plastic as a weed barrier is widely used and effective. The expense associated with black plastic as well as the ecological impact of disposal has a negative impact with its use. Research was conducted at Lane, Oklahoma on certified organic land at the USDA/OSU Wes Watkins research center to compare the impact of mulching types on weed control and herb yields. The 4 mulching treatments included black plastic, hay mulch (wheat and cereal rye), hay mulch over newsprint, and bare soil (no mulch). Four herbs, basil (Ocimum basilicum L.), sage (Salvia officinalis L.), garlic chives (Allium tuberosum Rottler ex Spreng.), and arugula [Eruca vesicaria (L.) Cav. ssp. sativa (Mill.) Thell.], were transplanted into the four mulching treatments in 4 replications. Weed control efficacy of the mulching treatments were determined by recording time required to maintain plots weed-free by hoeing and hand-weeding. Herb yields were determined for each mulching treatment. Arugula and garlic chives produced the best yields on black plastic. Basil and sage produced their highest yields when grown without a mulch (bare ground). The black plastic and bare soil treatments required the most time to handweed compared to the hay and hay/newsprint mulches, which required the least. The research demonstrated the importance of selecting the appropriate mulch for the specific herb and the potential benefits of natural and biodegradable mulches.

Technical Abstract: Reducing weed competition is a critical step in organic cropping systems. Use of black plastic as a weed barrier is widely used and effective. The expense associated with black plastic as well as the ecological impact of disposal has a negative impact with its use. Research was conducted at Lane, Oklahoma on certified organic land at the USDA/OSU Wes Watkins research center to compare the impact of mulching types on weed control and herb yields. The 4 mulching treatments included black plastic, hay mulch (wheat and cereal rye), hay mulch over newsprint, and bare soil (no mulch). Four herbs, basil (Ocimum basilicum L.), sage (Salvia officinalis L.), garlic chives (Allium tuberosum Rottler ex Spreng.), and arugula [Eruca vesicaria (L.) Cav. ssp. sativa (Mill.) Thell.], were transplanted into the four mulching treatments in 4 replications. Weed control efficacy of the mulching treatments were determined by recording time required to maintain plots weed-free by hoeing and hand-weeding. Herb yields were determined for each mulching treatment. Arugula and garlic chives produced the best yields on black plastic. Basil and sage produced their highest yields when grown without a mulch (bare ground). The black plastic and bare soil treatments required the most time to handweed compared to the hay and hay/newsprint mulches, which required the least. The research demonstrated the importance of selecting the appropriate mulch for the specific herb and the potential benefits of natural and biodegradable mulches.