Producers of organic vegetables often report that weeds are a troublesome production problem. It has been documented that corn gluten meal (CGM), a by-product of the wet-milling process of 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 potential use in organic vegetable production, especially in direct-seeded vegetables. Therefore, the objective of this research was to develop a mechanized method to uniformly apply CGM to the soil surface in either a broadcast or banded pattern. An applicator was assembled using various 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·m–2), and two application configurations (solid and banded). Field evaluations were conducted during Summer 2004 on 81-cm-wide raised beds at Lane, Okla. Differences between CGM formulations affected the flow rate within and between application configurations. The granulated formulation flowed at a faster rate, without clumping, compared to the powdered formulation. While the CGM in the banded configuration flowed faster than the solid application. It was determined that the CGM powder used with the solid application configuration was inconsistent, unreliable, and thus not feasible for use with this equipment without further modifications. These evaluations demonstrated the feasibility of using equipment, rather than manual applications, to apply CGM to raised beds for organic weed control purposes. Several design alterations may increase the efficiency and potential usefulness of this equipment. If research determines equivalent weed control efficacy between the two CGM formulations, the granulated formulation would be the preferred formulation for use in this equipment. This equipment would be useful for evaluating the benefits of banded applications of CGM for weed control efficacy and crop safety for direct seeded vegetables.
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