Effect of ammonium sulfate and water hardness on glyphosate and glufosinate activity in corn

Abstract

Soltani, N., Nurse, R. E., Robinson, R. E. and Sikkema, P. H. 2011. Effect of ammonium sulfate and water hardness on glyphosate and glufosinate activity in corn. Can. J. Plant Sci. 91: 1053–1059. Eight field trials were conducted over a 3-yr period (2008 to 2010) near Harrow and Ridgetown, Ontario, to evaluate the effect of water hardness (distilled: 0 ppm; intermediate: 353 ppm; and very hard 1799 ppm) on full label doses of glyphosate (900 g a.e. ha−1) and glufosinate (400 g a.i. ha−1) [with and without ammonium sulfate (AMS) at 2.5 L ha−1] efficacy in corn. There was no effect of water hardness on control of velvetleaf (ABUTH), redroot pigweed (AMARE), common lambsquarters (CHEAL), and annual grasses green foxtail (SETVI) and barnyardgrass (ECHCG) when glyphosate was applied with or without the AMS. There was also no difference in yield of corn with various water sources when glyphosate was applied with or without AMS. Glyphosate applied with various water sources with or without AMS controlled ABUTH, AMARE, CHEAL, and annual grasses better than glufosinate with or without AMS. Glufosinate with AMS, especially at the 1799 ppm water hardness, generally controlled ABUTH, AMARE, and CHEAL better than glufosinate without AMS, but there was no improvement in annual grass control. Contrasts indicated an 11% increase in yield when glufosinate was applied with AMS compared with when applied without AMS. Based on these results water hardness and AMS had little benefit on the efficacy of glyphosate in corn; however, efficacy of glufosinate was improved when applied with AMS at high water hardness.

WATER HARDNESS AND pH IN THE EFFECTIVENESS OF GLYPHOSATE FORMULATIONS

“…The authors evaluated Urochloa platyphylla, Ipomoea lacunosa, Amaranthus palmeri, and Cyperus esculentus. On the other hand, Soltani et al (2011) observe no differences in the control of various monocot and dicot weeds using water with different degrees of hardness (0, 353, and 1,799 ppm). This divergence of results could also be observed in the study of Manuchehri et al (2018).…”

“…Interference in the effectiveness of the applied product is rarely observed if only the pH is changed. Soltani et al (2011) found no differences in weed control (Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, and other grasses) with glyphosate using water with varying degrees of hardness.…”

The Response of Different Weed Species to Glyphosate Using Ammonium Sulfate and Hard Water

“…Pratt et al (2003) showed that hard water, defined as 500 mg L -1 CaCO 3 , reduced velvetleaf (Abutilon theophrasti L.) control by glyphosate while addition of AMS increased control. Although most of the research literature indicates that AMS can improve glyphosate efficacy (Wills and McWhorter 1985;Salisbury et al, 1991;Young et al, 2003), some authors reported no benefit of added AMS on glyphosate (Nurse et al, 2008;Soltani et al, 2011). Differential responses between weed species were noted by the authors.…”

“…ha -l , ammonium sulphate at 2% (w/v) in a distilled water spray carrier enhanced toxicity to H. annuus from 11 to 55% fresh weight reduction but reduced glyphosate toxicity in K. scoparia and G. max. Soltani et al (2011) reported no effect of water hardness on A. theophrasti, A. retroflexus, Chenopodium album, Setaria viridis and Echinochloa crus-galli control, when glyphosate was applied with or without AMS. With the widespread occurrence of glyphosate 3 resistant (GR) weeds, and because the effect of hard water and AMS on glyphosate toxicity is species dependent, optimum weed control in different species should be studied in weed species in more detail.…”

“…Differential responses between weed species were noted by the authors. AMS adjuvant enhancement of glyphosate phytotoxicity varied with different reports on different or similar species (Nalewaja and Matysiak, 1992;Nurse et al, 2008;Soltani et al, 2011). AMS at 0.5% (w/v) in a spray carrier containing calcium choloride (500 ppm calcium) overcame calcium antagonism of glyphosate toxicity to wheat (Triticum aestivum L.), overcame antagonism and enhanced toxicity to sunflower (Helianthus annuus), but only partly overcame calcium antagonism of toxicity to K. scoparia and soybean (Glycine max L.) (Nalewaja and Matysiak, 1992).With glyphosate at 100 g a.i.…”