EFFECTIVENESS OF SOME POST-EMERGENCE HERBICIDES IN SOYBEAN

Abstract

A three-year field experiment was conducted in soybean on lessive pseudogley soil at Čačinci locality (P.P. Orahovica d.d.) in North-eastern Croatia to evaluate the effectiveness of chemical weed control through single or multiple applications of post-emergence herbicides, alone or in combinations and their effects on soybean yields. Main weeds were summer annual species of Echinochloa crus-galli (140 - 269 shoots/m2), Ambrosia artemisiifolia (8-56 plants/m2) and Chenopodium album (3-12 plants/m2). All herbicide treatments showed high efficacy in control of annual grass- and broad-leaved weeds, but were ineffective against perennial weeds. Multiple applications of post-em. herbicide combinations of oxasulfuron + imazamox (92%), clethodim + fomesafen (93%) and oxasulfuron + imazamox + thifensulfuron methyl (94%) at reduced rates, provided better weed control compared to a single application of oxasulfuron (91%) and imazamox (89%) at recommended rates. No significant differences were observed in yields between herbicide treatments, ranging from 3395 kg to 3496 kg /ha, on average.

Keywords

• soybean
• weed density
• post-em. herbicides
• weed control (%)
• crop yield