Assessment of some herbicides for the control of purple nutsedge (Cyperus rotundus) in soybean (Glycine max (L.) Merrill)

Agahiu Ae Agahiu Ae

doi:10.30574/gscbps.2020.12.1.0191

Abstract

Field experiment was conducted at the Teaching and Research Farm, Faculty of Agriculture, Kogi State University, Anyigba in 2014 to assess the effects of some herbicides on the control of purple nutsedge in soybean. The field used for the trial was left fallow for about five years and predominantly infested with purple nutsedge. It was then ploughed, harrowed and ridged. The treatments applied consisted oflinuron [N-(3, 4-dichlorophenyl)-N-methoxy-N-methyl urea] at 2.0 and 2.5 kg a.i/ha; 2,4-D [ (2,4-dichlorophenoxy) acetic acid ] at 2.0 and 3.0 kg a.i/ha; glyphosate [N- (phosphonomethyl) glycine] at 2.0 and 2.5 kg a.i/ha; a tank mixture of glufosinate [2-amino-4- (hydroxymethylphosphinyl) butanoic acid] + fluazifop [ (R) -2-[5-(trifluoromethyl)-2- pyridinyl ] oxy] phenoxy] propanoic acid] at 2.5 and 3.0 kg a.i/ha, manual hoe weeding at 3,6 and 9 WAS and the weedy check. In this trial,the application of 2.0 and 2.5 kg a.i/ha of glyphosate was found to be most efficacious in the control of purple nutsedge. Glyphosate applied at both rates compared favourably with hoe weeding at 3,6 and 9 WAS in the control of purple nutsedge and resulted in the highest grain yield of soybean in the area. A tank mixture of glufosinate + fluazifop at 3.0 kg a;/ha equally gave a good control of purple nutsedge and the soybean grain yield produced therein was comparable to that obtained from plots treated with both rates of glyphosate or that were hoe weeded. Results obtained in this study suggest that glyphosate applied at 2.5 kg a.i/ha could provide alternative management option for the control of purple nutsedge to manual hoe-weeding and for ensuring higher grain yield of soybean.

Highlights

Soybean (Glycine max (L.) Merrill) an erect, much branched pubescent annual belongs to the family leguminosae sub family papilionoidae and the genus Glycine L
The weed control score at 8 WAS in plots treated with 2.0 and 2.5 kg a.i/ha of glyphosate and 3.0 kg a.i/ha each of 2,4-D and glufosinate + fluazifop was much higher in comparison with the other treatments except the hoe weeded plots
Weed biomass was most minimal with the application of 2.0 and 2.5 kg a.i/ha of glyphosate with the least been recorded on plots that were hoe weeded

Summary

Introduction

Soybean (Glycine max (L.) Merrill) an erect, much branched pubescent annual belongs to the family leguminosae sub family papilionoidae and the genus Glycine L. Purple nutsedge ranks among the world’s worst weeds. Purple nutsedge (Cyperus rotundus) is a glumifloral monocotyledon belonging to the family, Cyperaceae. It causes severe depression in soybean grain yield if left uncontrolled in the crop life cycle especially during the early growth stage [4]. Green KA (2011) reported soybean grain yield loss of up to 80% by purple nutsedge infestation. As revealed by Watson and Kent (2005), alachlor reduced the growth of purple nutsedge but achieved only marginal control. Purple nutsedge, where it predominates has caused 65-72% grain loss in soybean [7]. Earlier work carried out indicated that alachlor and metolachlor delayed sprouting of tubers and killed shoots of yellow nutsedge and revealed that their control on the weed (purple nutsedge) was temporary [8; 9; 10; 11; Corresponding author: Agahiu AE

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Discussion

Conclusion