Velvetleaf and Giant Foxtail Control for Solid-Seeded Soybean Production in Three Tillage Intensities

Abstract

Soybean [Glycine max (L.) Merr.] production in conservation tillage systems continues to increase due to economic and environmental considerations. Cultural practices such as weed control must be reevaluated for conservation tillage systems. This research was conducted to determine if tillage intensity influenced herbicidal weed control. Field experiments were conducted during 1984 and 1985 at Arlington and Janesville, WI, to compare herbicide efficacy in no-till, reduced tillage, and conventional tillage systems. Soybean was planted in 8-in. rows directly into corn (Zea mays L.) residue for no-till, following paraplowing for reduced tillage, and following moldboard plowing and secondary tillage for conventional tillage. Giant foxtail (Setaria faberi Herrm.) control was often less under no-till or reduced tillage conditions than conventional tillage with the same herbicide treatment. Velvetleaf (Abutilon theophrasti Medik.) control with bentazon [3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide; Basagran, BASF Corp., Porsippany, NJ] was nearly complete for all tillage systems, but with acifluorfen {5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid; Blazer, BASF Corp., Parsippany, NJ} control was not complete in conventional tillage. Pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine; Prowl, American Cyanamid, Wayne, NJ] applied preemergence reduced soybean survival at Arlington. Soybean injury with all other herbicide treatments was minimal and was not influenced by tillage systems. Soybean yield was not influenced by tillage systems under weed-free conditions. Differences in soybean yield among tillage systems with the same herbicide treatment appeared to be due to differences in weed control. These data indicate that solid-seeded soybean production can be successful and weeds can be controlled under conservation tillage systems.