Evaluation of herbicide mixtures for weed control in soybean (Glycine max) in southern Nigeria

Abstract

An experiment was conducted during 1991 and 1992 to evaluate herbicide mixtures for controlling weeds in soybean [Glycine max(L.) Merr.] at Makurdi in Nigeria. Post-emergence application of sethoxydim + imazethapyr (0.37 + 0.10 kg/ha) as tank-mix gave the highest grain yield (2.47 tonnes/ha). followed by fluazifop + imazcethapyr(O.25 + O. 10 kg/ha) (2,46 tonnes/ha): pre-emergence application of imazaquin + pendimethalin (0.72 + 1.25 kg/ha) (2.44tonnes/ha). imazethapyr+ pendimethalin(0.23 + 1.13 kg/ha) (2.20 tonnes/ha) and metobromuron + metolachlor (1.25 + 1.25 kg/ha) (2.12 tonnes/ha). Increased grain yield was on account of reduced weed biomass. Those yields were comparable to those from plots weeded with hoe 2 and 3 times. Weed-control efficiency was 60.7-77.2% for herbicides and 61.4- 82.9% for weeding with hoe. Uncontrolled growth of weeds in the unweeded control reduced the grain and stover yields by 51 and 66% respectively.