Corn Gluten Meal Applicator for Weed Control in Organic Vegetable Production

Producers of organic vegetables often report that weeds are their most troublesome production problem. Corn gluten meal (CGM), a by-product of the wet-milling process Qf corn, is phytotoxic. As a preemergence or preplant-incorporated herbicide, CGM inhibits root development, decreases shoot length, and reduces plant survival of weed or crop seedlings. The development of a mechanized application method for CGM and the ability to apply the material in a banded pattern would increase its use in organic vegetable production, especially in direct-seeded vegetables. The objective ~as to develop a mechanized method to uniformly apply CGM to the soil surface in either a solid (broadcast) or banded pattern. An applicator was assembled using various Charles L. Webber, ill (E-mail: [email protected]) is affiliated with the United States Department of Agriculture, Agricultural Research Service, South Central Agricultural Research Laboratory, P.O. Box 159, Lane, OK 74555. James W. Shrefler (E-mail: [email protected]) is affiliated with Department of Horticulture and Landscape Architecture, Oklahoma State University, P.O. Box 128, Lane, OK 74555. Address correspondence to: Charles L. Webber, ill at the above address. The authors thank Buddy L. Faulkenberry, for his participation in designing, assembling, calibrating, and field-testing the com gluten meal application equipment. The article was prepared by a USDA employee as part of his official duties. Copyright protection under US copyright law is not available for such works, and there is no copyright to transfer. The fact that the private publication in which the article appears is itself copyrighted does not affect the material that is a work product of the US Government, which can be freely reproduced by the public. Mention of a trademark, vendor, or proprietary product does not constitute a guarantee or warranty of the product by the USDA and does not imply its approval to the exclusion of other produCts that may also be suitable. Journal of Vegetable Science, Vol. 12(4) 2006 Available online at http://jvs.haworthpress.com © 2006 by The Haworth Press, Inc. All rights reserved. doi: 10. 1300/J484v12n04_03 20 JOURNAL OF VEGETABLE SCIENCE machinery components (fertilizer box, rotating agitator blades, 12-volt motor, and fan-shaped, gravity-fed, row-banding applicators). The equipment was evaluated for the application of two CGM formulations (powdered and granulated), three application rates (250, 500, and 750 g/m2), and two application configurations (solid and banded). Field evaluations were conducted during the summer of 2004 on 81 cm wide raised beds at Lane, OK. Differences between CGM formulations affected· flow rate within, and between, application configurations. The granulated formulation flowed at a faster rate, without clumping, compared with the powdered formulation, while the CGM in the banded configuration flowed faster than the solid application. The delivery of CGM powder with the solid application configuration was inconsistent and unreliable, and therefore this material is considered impracticable when used in this configuration without further modifications to the equipment. The feasibility of using equipment, rather than manual applications, to apply CGM to raised beds for organic weed control purposes was demonstrated. Equipment alterations will increase the efficiency and potential usefulness of this equipment. If future research determines that the weed control efficacy between the two CGM formulations is equivalerit, the granulated formulation would be the preferred one for use in this application equipment because it flows more smoothly. This equipment would be useful for evaluating benefits of banded applications of CGM for weed control efficacy and crop safety for direct-seeded vegetables. doi: 1O.1300/J484v12n04_03 [Article copies availableforafeefrom The Haworth Document Delivery Service: I -800-HAWORTH. E-mail address: Website: © 2006 by The Haworth Press, Inc. All rights reserved.]