Efficacy of Corn Gluten Meal for Common Dandelion and Smooth Crabgrass Control Compared to Nitrogen Fertilizers

Abstract

Corn gluten meal (CGM) is a naturally derived weed control/fertilizer that may allow for reduction in herbicide use on turfgrass. Previously it has been reported that CGM inhibits root production and reduces naturally occurring weed populations. It is unclear if weed population reductions are due to herbicidal activity or increased competition of the turfgrass species from nitrogen in CGM. Our objective was to compare three N sources (CGM, Milorganite, and urea) with three application strategies (equivalent of 1.8 lb N/1000 ft² with half applied in spring plus half applied in fall, 3.6 lb N/1000 ft² with half applied in spring plus half applied in fall, and 3.6 lb/1000 ft² applied in spring). CGM provided equivalent or lower quality ratings compared to Milorganite or urea throughout the two-year study. Common dandelion (Taraxacum officinale G.H. Weber ex Wiggers) counts (0 to 1004/100 ft²) and smooth crabgrass [Digitaria ischaemum (Shreb) Shreb. ex Muhl.] coverage (5 to 90%) were similar for treatments receiving CGM, Milorganite, and urea. In this study, CGM provided no additional benefit in weed control compared to products containing only N. Fertilizing with 3.6 lb of N/1000 ft² resulted in higher turf quality with less weeds than plots receiving only 1.8 lb of N/1000 ft².