Title: Post-emergence weed control through abrasion with an approved organic fertilizer
Abstract: Corn gluten meal (CGM) is an approved organic fertilizer and pre-emergence herbicide that can be manufactured in the form of grit. This grit was tested for its ability to abrade seedlings of the summer annual weedy grass, Setaria pumila, when plants were in the 1- to 5-leaf stages of growth. CGM was propelled at air pressures of 250–750 kPa at distances of 30–60 cm from the plants. Established seedlings of S. pumila were controlled more effectively when grit was applied at 500 and 750 kPa than at 250 kPa, as well as when the applicator's nozzle was 30 cm from the plants compared to 60 cm distance. Seedling growth and dry weights were greatly reduced by exposures to grit at 60 cm and 500 kPa for 2 s or less, and seedlings were nearly completely destroyed at 30 cm distance and 750 kPa. CGM, a soft grit, was as effective for abrading seedlings as fine quartz sand, a hard grit. CGM had little pre-emergence herbicidal effect on S. pumila. Although regrowth can occur in S. pumila after abrasion by grit, the initial grit-induced stunting is sufficient to allow competing crop plants, like maize, to escape competition and suppress the weed. Consequently, CGM may be an effective form of soft grit for post-emergence abrasion of seedlings of summer annual grass weeds in organic row crops, while simultaneously supplying the crop with fertilizer. [Frank Forcella, Trevor Jamesand Anis Rahman (2011). Post-emergence weed control through abrasion with an approved organic fertilizer, Renewable Agriculture and Food Systems, 6: 31-37. DOI: 10.1017/S1742170510000438]