A Recirculating Spray System for Postemergence Weed Control in Row Crops

Abstract

A recirculating sprayer was developed for applying herbicides in row crops to weeds taller than the crop. Herbicide solutions are applied through solid stream nozzles above and at right angles to the rows, so that a trap collects herbicide spray not deposited on weeds. Trapped solution is returned to the original spray tank by gravity flow. Good to excellent control of pigweed (Amaranthus spp.), cocklebur (Xanthium spp.), and sesbania (Sesbania spp.) was obtained with (2,4-dichlorophenoxy)acetic acid (2,4-D) while monosodium methanearsonate (MSMA) effectively controlled johnsongrass (Sorghum halepense (L.) Pers.). The better treatments increased the harvested yields of soybeans (Glycine max (L.) Merr., var. Lee) 6 to 8 bu/A when weed infestations were severe at time of treatment. Use of the sprayer permits treatment with herbicides normally considered too toxic to crops, and reduces costs through recovery of most of the herbicide solution that is not intercepted by weeds.