Preemergence Weed Control in a Conservation Tillage Cotton (Gossypium hirsutum) Cropping System on Sandy Soils

Abstract

Field experiments were established on a loamy fine sand to evaluate weed control in a conservation tillage system where cotton was planted into sorghum stubble. Preemergence herbicides for Palmer amaranth and volunteer sorghum control in cotton included methazole, dipropetryn, prometryn, metolachlor, and metolachlor plus dipropetryn or prometryn. Dipropetryn controlled both weeds without crop injury. Above 1.7 kg ai/ha, methazole provided effective control but injured the crop. Prometryn was less effective than dipropetryn or methazole against Palmer amaranth and controlled <40% volunteer sorghum. Metolachlor unacceptably injured cotton. Cotton yields were excellent when both weeds were controlled.