2019 ASHS Annual Conference

Biobased crop management inputs are renewable and promote landscape-scale carbon and nutrient recycling. At the farm-scale, biobased inputs can provide multiple agronomic functions, including weed control, and can be less toxic to humans and the environment than synthetic inputs. Corn and soybean production and industrial processing (e.g., biofuels) in the Midwest U.S. results in a number of byproducts, including corn gluten meal (CGM) and soybean meal (SM), that have potential value as biobased crop management inputs. Our objective is to develop new products from and application technologies for corn and soybean processing byproducts in specialty crops. Toward this objective, we have conducted many lab, greenhouse, and field tests over the last five years to: 1) develop an abrasive weeding applicator and application recommendations for granulated CGM and SM grits, 2) integrate weed and nitrogen management with banded applications of CGM and SM in the crop row, and 3) develop formulations of and application technology for sprayable mulch films for in-row weed control. CGM and SM applied as abrasive grits reduced in-row weed density up to 97%, depending on weed community composition, density, and growth stage, which led to a 10%-45% increase in crop yield relative to a weedy control. High rates of CGM and SM (1.2 – 4.4 kg/m²) banded in the crop row after crop transplanting (but prior to weed emergence) consistently reduced weed emergence in tomato (Solanum lycopersium L.) and broccoli (Brassica oleracea L. var. italica), and increased mineral soil nitrogen, but was also toxic to tomato plants in one season and reduced yield. Sprayable film solutions containing water, glycerol, corn starch, corn gluten meal, and soy protein isolate reduced weed biomass by approximately 79% and 87% when applied before and after weed emergence, respectively (at rates between 5.1-10.2 L/m²). Water is the primary ingredient in the sprayable solutions (63%-77%), but we aim to reduce water content and are developing a high-viscosity applicator that would enable reduced application volumes and cost on a field-scale. Collectively, results demonstrate the agronomic value of corn and soybean byproducts as inputs in specialty crop systems, but further research and development are needed prior to commercialization and on-farm adoption of the proposed technologies and tactics.