Propelled Abrasive Grit for Weed Control in Organic Silage Corn

Abstract

Core Ideas Air‐propelled corncob grit can control in‐row weeds in corn through abrasionA single grit application applied at V1 or V3 of corn increased silage yield.A single grit application applied at V5 or V7 suppressed weeds, but had lower silage yield. Weed management in organic farming requires many strategies to accomplish acceptable control and maintain crop yields. This 2‐yr field study used air propelled abrasive grit for in‐row weed control in organically certified silage corn (Zea mays L.). Corncob grit was applied as a single application at corn vegetative growth stages V1 (one true leaf; numbers correspond to number of true leaves at the corn vegetative stage), V3, or V5 (in 2013) and V3, V5, and V7 (in 2014) and in double and triple combinations at these stages. Between‐row weed control was accomplished by flaming or cultivation after the last grit application. Grit effects on weed efficacy and silage yield were quantified and compared with hand‐weeded and season‐long weedy treatments. Grit applications decreased in‐row weed biomass by >80% and increased yield up to 250% when compared with the weedy check. Single early applications (V1 and V3) increased yield, with additional treatments decreasing end‐of‐season weed density and biomass. Single late grit applications (V5 and V7) also decreased weed biomass, but silage yields were reduced compared with hand‐weeded and early treatments. Early grit applications may have value for growers to control in‐row annual weeds in organic silage corn without soil disturbance.

Broadleaf weed control with abrasive grit during raspberry establishment

“…For WCROC and Fairhaven Farm, grit particles were approximately 0.5 mm in diameter and had a specific gravity (±SE) of 0.43 ± 0.005 g cm −3 ; these characteristics matched corn-cob grits used by others (Erazo-Barradas et al 2018. At Prairie Horizon Farm, however, organically certified grit was used, which had a particle diameter of 1 mm and specific gravity of 0.54 ± 0.005 g cm −3 .…”

“…Weeding times and required grit amounts for control of only broadleaf weeds in raspberry remain unknown. In corn, only two to three grit-weeding events, and considerably less grit, were needed for season-long weed control (Erazo-Barradas et al 2018. This probably occurred because corn canopies develop quickly and suppress the growth of many weeds, especially late-germinating species.…”

Using Abrasive Grit for Weed Management in Field Crops

“…In-row (IR) grits were applied twice, at the V1 and V5 maize growth stages, and the V1 and V3 soybean growth stages ( Table 1). About 800 kg ha −1 of grit was used for each application, which was applied using a propelled abrasive grit applicator [PAGMan] that sprays four rows simultaneously, with a nozzle on each side of the row [69,70]. Distance of the nozzle tip to the base of the maize plants was between 10 and 15 cm, at a 45° contact angle.…”

“…Air-propelled abrasive grit application for weed control by tissue abrasion was proposed by Nørremark et al [62]. Numerous types of grits made from agricultural (e.g., maize cobs and walnut shells), non-agricultural (e.g., sand), and organic fertilizer (e.g., soybean meal and corn gluten meal) materials controlled weeds in greenhouse and field settings [63][64][65][66][67][68][69][70] when sprayed at high pressure (800 kPa). In the field, two or three in-row grit applications, applied from V1 to V5 growth stage of maize, could reduce weeds and increase grain or silage yields [65,69,70].…”

Propelled abrasive grit applications for weed management in transitional corn grain production

“…In field experiments, Forcella (2012) reported that two applications of air-propelled corncob grit aimed at the row, combined with inter-row cultivation reduced weed presence in corn and increased yield. Erazo-Barradas (2016) demonstrated that in certified organic silage corn, early in-row grit applications (V1 and V3 stages of corn growth) effectively controlled weeds and maintained high crop yields, but later applications (V5 and V7) reduced corn yields due to prolonged crop–weed interference. Thus, in-row grit applications at optimum timings, combined with between-row weed control techniques, may provide unique weed management tools for post-emergence weed control in organic corn.…”