Tillage and Cover-cropping Affect Weed Populations and Yield of Broccoli and Cauliflower

Abstract

Research was conducted to determine whether tillage in the fall rather than spring could be used to prepare fields for transplanting broccoli and cauliflower crops. Because fall-tilled soils are prone to erosion by winter rains, the effects of a fall-planted barley cover crop were also determined. Trifluralin was applied to the spring-tilled plots, according to grower practice. Herbicide treatments applied to fall-tilled plots were early and/or late applications of glyphosate and napropamide following early and late glyphosate applications. Weed emergence was generally increased by the barley cover crop, but the species depended on which herbicides were applied. Napropamide reduced the emergence of some weed species, whether or not a cover crop was grown. Yield of broccoli was reduced by the cover crop, and was highest in fall-tilled plots that received two glyphosate treatments. Yield of cauliflower was highest in spring-tilled plots that were cover-cropped. In fall-tilled plots, cauliflower response to the cover crop and herbicide treatments was inconsistent.