Benefit of Adding Ammonium Sulfate or Additional Glyphosate to Glyphosate in Corn and Soybean

Nader Soltani,Robert E Nurse,Peter H Sikkema,Christy Shropshire

doi:10.4236/as.2016.710070

Abstract

Nine field trials (4 in corn and 5 in soybean) were conducted over 2 years (2014 and 2015) to determine if there is greater benefit of adding ammonium sulfate (AMS) (2.5 L·haˉ1) or an equal dollar value of glyphosate (406 g·ae·haˉ1) to glyphosate applied at 450, 675 or 900 g·ae·haˉ1 for weed control in corn and soybean. Glyphosate applied at 450 g·ae·haˉ1 controlled velvetleaf 90% to 98%, common ragweed 80% - 97%, common lambsquarters 91% - 99%, Eastern black nightshade 83% - 100% and barnyardgrass 73% - 97% in corn and common ragweed 37% - 89%, common lambsquarters 39% - 98%, barnyardgrass 90% - 98% and green foxtail 91% - 98% in soybean. The addition of AMS to glyphosate applied at 450, 675 or 900 g·ae·haˉ1 provided little to no added benefit for the control of velvetleaf, common ragweed, common lambsquarters, Eastern black nightshade, barnyardgrass and green foxtail in corn and soybean. There was a greater benefit in weed control efficacy by simply adding and equal dollar value of glyphosate (406 g·ae·haˉ1) than AMS (2.5 L·haˉ1) to glyphosate. There was no difference in corn or soybean yield among the herbicide treatments evaluated. Based on these results, addition of AMS to glyphosate at rates evaluated had little benefit on weed control efficacy or yield of corn and soybean.

Highlights

Nurse et al [7] has shown benefit of adding ammonium sulfate (AMS) to glyphosate at low dose (225 g∙ha−1) shortly after application (7 DAA) for control of velvetleaf (Abutilon theophrasti Medic.), at the same time there were no benefit for control of common lambsquarters (Chenopdium album L.), redroot pigweed (Amaranthus retroflexus L.), and annual grasses such as foxtails (Setaria spp.)
450, 675 or 900 g∙ae∙ha−1 provided no consistent benefit for the control of velvetleaf, common ragweed, common lambsquarters, Eastern black nightshade and barnyardgrass in corn and common ragweed, common lambsquarters, barnyardgrass and green foxtail in soybean
There was no difference in corn or soybean yield among the herbicide treatments evaluated

Summary

Introduction

The Ontario corn and soybean industry covers about 2,000,000 ha, and has annual. Weed Committee are representatives of the commodity groups such as corn, soybean, wheat and edible beans, industry personnel and public research scientists). More than 90% of the corn and 79% of soybean produced in Ontario are seeded to glyphosate-resistant hybrids/cultivars [2]. Glyphosate-resistant corn and soybean provide Ontario crop producers cost-effective weed management options that are efficacious and environmental friendly [3]. Instead NH 4+ binds with the glyphosate molecule which results in greater absorption of glyphosate into the leaves and improves weed control [6]

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Results

Conclusion