Effect of Carrier Water Hardness and Ammonium Sulfate on Efficacy of 2,4-D Choline and Premixed 2,4-D Choline Plus Glyphosate

2016 ◽  
Vol 30 (4) ◽  
pp. 878-887 ◽  
Author(s):  
Pratap Devkota ◽  
William G. Johnson

Spray water quality is an important consideration for optimizing herbicide efficacy. Hard water cations in the carrier water can reduce herbicide performance. Greenhouse studies were conducted to evaluate the influence of hard water cations and the use of ammonium sulfate (AMS) on the efficacy of 2,4-D choline and premixed 2,4-D choline plus glyphosate for giant ragweed, horseweed, and Palmer amaranth control. Carrier water hardness was established at 0, 200, 400, 600, 800, or 1,000 mg L−1using CaCl2and MgSO4, and each hardness level consisted of without or with AMS at 10.2 g L−1. One-third of the proposed use rates of 2,4-D choline at 280 g ae ha−1and 2,4-D choline plus glyphosate at 266 plus 283 g ae ha−1, respectively, were applied in the study. An increase in carrier water hardness showed a linear trend for reducing 2,4-D choline and 2,4-D choline plus glyphosate efficacy on all weed species evaluated in both studies. The increase in water hardness level reduced giant ragweed control with 2,4-D choline and the premix formulation of 2,4-D choline plus glyphosate to a greater extent without AMS than it did with AMS in the spray solution. Increases in water hardness from 0 to 1,000 mg L−1reduced weed control 20% or greater with 2,4-D choline. Likewise, the efficacy of the premixed 2,4-D choline plus glyphosate was reduced 21% or greater with increased water hardness from 0 to 1,000 mg L−1. The addition of AMS improved giant ragweed, horseweed, and Palmer amaranth control ≥ 17% and ≥ 10% for 2,4-D choline and 2,4-D choline plus glyphosate application, respectively. The biomass of all weed species was reduced by ≥ 8% and ≥ 5% with 2,4-D choline and 2,4-D choline plus glyphosate application, respectively, when AMS was added to hard water.

2020 ◽  
Vol 34 (1) ◽  
pp. 107-116 ◽  
Author(s):  
Geoffrey P. Schortgen ◽  
Aaron J. Patton

AbstractHerbicides are an important tool in managing weeds in turf and agricultural production. One of the earliest selective herbicides, 2,4-D, is a weak acid herbicide used to control broadleaf weeds. Water-quality parameters, such as pH and hardness, influence the efficacy of weak acid herbicides. Greenhouse experiments were conducted to evaluate how varying water hardness level, spray solution storage time, and adjuvant inclusion affected broadleaf weed control by 2,4-D dimethylamine. The first experiment evaluated a range of water-hardness levels (from 0 to 600 mg calcium carbonate [CaCO3] L−1) on efficacy of 2,4-D dimethylamine applied at 1.60 kg ae ha−1 for dandelion and horseweed control. A second experiment evaluated dandelion control from spray solutions prepared 0, 1, 4, 24, and 72 h before application. Dandelion and horseweed control by 2,4-D dimethylamine was reduced when the CaCO3 level in water was at least 422 or at least 390 mg L−1, respectively. Hard-water antagonism was overcome by the addition of 20 g L−1 ammonium sulfate (AMS) into the mixture. When AMS was included in spray mixtures, no differences were observed at 600 mg CaCO3 L−1, compared with distilled water. Spray solution storage time did not influence dandelion control, regardless of water-hardness level or adjuvant inclusion. To prevent antagonism, applicators should use a water-conditioning agent such as AMS when applying 2,4-D dimethylamine in hard water.


2016 ◽  
Vol 30 (1) ◽  
pp. 116-122 ◽  
Author(s):  
Pratap Devkota ◽  
Fred Whitford ◽  
William G. Johnson

Water is the primary carrier for herbicide application, and carrier-water–related factors can influence herbicide performance. In a greenhouse study, premixed formulation of glyphosate plus dicamba was mixed in deionized (DI) water at 5, 18, 31, 44, or 57 C and applied immediately. In a companion study, glyphosate and dicamba formulation was mixed in DI water at temperatures of 5, 22, 39, or 56 C and sprayed after the herbicide solution was left at the respective temperatures for 0, 6, or 24 h. In both studies, glyphosate plus dicamba was applied at 0.275 plus 0.137 kg ae ha−1(low rate), and 0.55 plus 0.275 kg ha−1(high rate), respectively, to giant ragweed, horseweed, Palmer amaranth, and pitted morningglory. Glyphosate plus dicamba applied at a low rate with solution temperature of 31 C provided 14% and 26% greater control of giant ragweed and pitted morningglory, respectively, compared to application at solution temperature of 5 C. At both rates of glyphosate and dicamba formulation, giant ragweed and pitted morningglory control was 15% or greater at solution temperature of 44 C compared to 5 C. Weed control was not affected with premixture of glyphosate and dicamba applied ≤ 24 h after mixing herbicide. When considering solution temperature, glyphosate and dicamba applied at low rate provided 13 and 6% greater control of Palmer amaranth and pitted morningglory, respectively, with solution temperature of 22 C compared to 5 C. Similarly, giant ragweed control was 8% greater with solution temperature of 39 C compared to 5 C. Glyphosate and dicamba applied at high rate provided 8% greater control of giant ragweed at solution temperature of 22 or 39 C compared to 5 C. Therefore, activity of premixed glyphosate and dicamba could be reduced with spray solution at lower temperature; however, the result is dependent on weed species.


2016 ◽  
Vol 30 (4) ◽  
pp. 848-859 ◽  
Author(s):  
Pratap Devkota ◽  
William G. Johnson

Carrier water quality is an important consideration for herbicide efficacy. Effect of carrier water pH (4, 6.5, or 9) and coapplied Zn or Mn foliar fertilizer was evaluated on glufosinate efficacy for horseweed and Palmer amaranth control in the field. Greenhouse studies were conducted to evaluate the effect of: (1) carrier water pH, foliar fertilizer (Zn, Mn, or without fertilizer), and ammonium sulfate (AMS) (at 0 or 2.5% v/v); and (2) carrier water hardness (0 to 1,000 mg L−1) and AMS (at 0 or 2.5% v/v) on glufosinate efficacy for giant ragweed, horseweed, and Palmer amaranth control. In a 2014 field study, control, plant density reduction, and biomass reduction were at least 8% greater for horseweed and at least 14% greater for Palmer amaranth when glufosinate was applied at carrier water pH 4 compared with pH 9. Glufosinate efficacy was at least 10 and 17% greater for giant ragweed and Palmer amaranth control, respectively, with carrier water pH 4 compared with pH 9 in the greenhouse. In the greenhouse studies, coapplied Zn or Mn fertilizer had no effect on glufosinate efficacy. Increased carrier water hardness from 0 to 1,000 mg L−1negatively influenced glufosinate efficacy and resulted in 20 and 17% lesser control and biomass reduction, respectively, on giant ragweed or Palmer amaranth. Use of AMS enhanced glufosinate efficacy on giant ragweed control in both greenhouse studies, whereas only the Palmer amaranth control was enhanced in the water hardness study. Horseweed control with glufosinate as affected by carrier water pH, hardness, or AMS remained unaffected in both greenhouse studies. Carrier water at alkaline pH or hardness > 200 mg L−1has potential to reduce glufosinate efficacy. Therefore, carrier water free of hardness cations and at acidic condition (pH = 4 to 6.5) should be considered for optimum glufosinate efficacy.


2019 ◽  
Vol 34 (1) ◽  
pp. 101-106
Author(s):  
Pratap Devkota ◽  
William G. Johnson

AbstractHerbicide carrier water hardness and pH can be variable depending on the source and geographic location. Herbicide efficacy can be affected by the pH and hardness of water used for spray solution. Field and greenhouse studies were conducted to evaluate the effect of carrier water pH and hardness on premixed dicamba and glyphosate efficacy. Treatments were combinations of water pH at 4, 6.5, or 9; and water hardness at 0 (deionized water), 400, or 800 mg L−1 of CaCO3 equivalent. In the field study, dicamba and glyphosate were applied at 0.55 and 1.11 kg ae ha−1, respectively, and half of these rates were applied in the greenhouse study. There was no interaction between carrier water pH and hardness on dicamba and glyphosate efficacy; however, the main effects of carrier water pH and hardness were significant. Herbicide efficacy was reduced with carrier water at pH 9 compared with pH 4. In the field study, common lambsquarters, common ragweed, horseweed, or Palmer amaranth control was improved 6% or more at carrier water at pH 4 compared with pH 9. Similar results were observed with water pH for giant ragweed, Palmer amaranth, or pitted morningglory control in the greenhouse study. Carrier water hardness at 400 or 800 mg L−1 reduced common ragweed, giant ragweed, or horseweed control compared with 0 mg L−1. Similarly, common lambsquarters, Palmer amaranth, or pitted morningglory control was reduced at least 10% with carrier water hardness at 800 mg L−1 compared with 0 mg L−1. These results indicate carrier water at acidic pH and of no hardness is critical for dicamba and glyphosate application, and spray solution needs to be amended appropriately for an optimum efficacy.


2019 ◽  
Vol 33 (04) ◽  
pp. 562-568 ◽  
Author(s):  
Pratap Devkota ◽  
William G. Johnson

AbstractCarrier water pH is an important factor for enhancing herbicide efficacy. Coapplying agrochemical products with the herbicide might save time and resources; however, the negative effect of foliar fertilizers on herbicide efficacy should be thoroughly evaluated. In greenhouse studies, the effect of carrier water pH (4, 6.5, and 9), foliar fertilizer (zinc [Zn], manganese [Mn], or without fertilizer), and ammonium sulfate (AMS) at 0% or 2.5% vol/vol was evaluated on 2,4-D and premixed 2,4-D plus glyphosate efficacy for giant ragweed, horseweed, and Palmer amaranth control. In addition, a field study was conducted to evaluate the effect of carrier water pH (4, 6.5, and 9); and Zn or Mn foliar fertilizer on premixed 2,4-D plus glyphosate efficacy for horseweed and Palmer amaranth control. In the greenhouse study, 2,4-D and premixed 2,4-D plus glyphosate provided 5% greater weed control at acidic compared with alkaline carrier water pH. Coapplied Mn foliar fertilizer reduced 2,4-D and premixed 2,4-D plus glyphosate efficacy at least 5% for weed control. Addition of AMS enhanced 2,4-D and premixed 2,4-D plus glyphosate efficacy at least 6% for giant ragweed, horseweed, and Palmer amaranth control. In the field study, few significant differences occurred between coapplied Zn or Mn foliar fertilizer for any treatment variables. Therefore, carrier water pH, coapplied foliar fertilizer, and water-conditioning adjuvants have potential to influence herbicide performance. However, weed species could play a role in the differential response of these factors on herbicide efficacy.


2016 ◽  
Vol 30 (3) ◽  
pp. 617-628 ◽  
Author(s):  
Pratap Devkota ◽  
Douglas J. Spaunhorst ◽  
William G. Johnson

Carrier water pH, hardness, coapplied foliar fertilizer, water conditioning agents, and plant height are critical considerations for optimum herbicide performance. Field studies were conducted to evaluate the effect of carrier water pH (4, 6.5, and 9) and zinc (Zn) or manganese (Mn) foliar fertilizer on mesotrione for horseweed and Palmer amaranth control. Additionally, effect of carrier water pH and foliar fertilizer was evaluated on 7.5-, 12.5-, and 17.5-cm tall horseweed. Greenhouse treatments consisted of carrier water pH and foliar fertilizer (Zn, Mn, or without fertilizer); or water hardness (0 to 1,000 mg L−1) in the presence or absence of ammonium sulfate (AMS) for mesotrione control of giant ragweed, horseweed, and Palmer amaranth. Mesotrione activity was greater on horseweed with carrier water pH 6.5 compared to pH 4 or 9. Coapplied Zn fertilizer reduced mesotrione activity on Palmer amaranth in the field study in 2014 and horseweed in the greenhouse study. Mesotrione efficacy was greatly influenced by horseweed height. Percent control ranged from 96 to 99%, 75 to 89%, or 61 to 64% with mesotrione applied on 7.5-, 12.5-, or 17.5-cm tall horseweed, respectively, and results were similar for plant height and dry weight reduction. Increasing carrier water hardness from 0 to 1,000 mg L−1reduced mesotrione efficacy 28, 18, and 18% (or greater) on giant ragweed, horseweed, and Palmer amaranth, respectively. The addition of AMS enhanced mesotrione efficacy 9, 6, or 9% (or greater) for giant ragweed, horseweed, and Palmer amaranth control, respectively. Mesotrione should be applied at near neutral carrier water pH, hardness < 200 mg L−1, and with AMS for achieving optimum weed control.


2019 ◽  
Vol 37 ◽  
Author(s):  
M. MIRZAEI ◽  
M. RASTGOO ◽  
K. HAJMOHAMMADNIA GHALIBAF ◽  
E. ZAND

ABSTRACT: Water hardness antagonism and the effect of ammonium sulphate (AMS) on efficacy of glyphosate have been well documented. However conflicting results between weed species were noted by the authors. Greenhouse experiments were conducted twice at the Ferdowsi University of Mashhad in a randomized complete block design with a factorial arrangement and three replications during 2014-2015. Four experiments were arranged separately on cypress (Kochia scoparia), redroot pigweed (Amaranthus retroflexus), little seed canary grass (Phalaris minor) and winter wild oat (Avena ludoviciana) using ammonium sulphate and deionizad water and in the presence of different salts, (i.e. NaHCO3, CaCO3, MgCl2 and CaCl2 at 500 ppm) against three doses of glyphosate (256.25, 512.5 and 1,025 g a.i. ha-1), with and without ammonium sulphate (AMS) as adjuvant (2% w/v). The results showed the application of AMS overcomes the inhibitory effects of salts in the spray solution in tested species. The degree of effectiveness in A. retroflexus was more than A. ludoviciana and P. minor. Glyphosate with AMS caused reduction in dry matter in grasses from 0.34 to 0.28 g, while glyphosate toxicity in A. retroflexus with AMS was 100 percent and all of the plants were destroyed (0.82 to 0 g). The application of AMS in overcoming the inhibitory effects of water hardness had no effect on K. scoparia control. However, Increasing AMS could overcome the inhibitory effects of hard water in the spray solution on glyphosate efficacy in A. retroflexus and K. scoparia, but it had no effect on tested grassy weeds. We may conclude that glyphosate work differently on weed species using AMS and hard water.


2014 ◽  
Vol 94 (8) ◽  
pp. 1401-1405 ◽  
Author(s):  
K. J. Mahoney ◽  
R. E. Nurse ◽  
P. H. Sikkema

Mahoney, K. J., Nurse, R. E. and Sikkema, P. H. 2014. The effect of hard water, spray solution storage time, and ammonium sulfate on glyphosate efficacy and yield of glyphosate-resistant corn. Can. J. Plant Sci. 94: 1401–1405. Effects of ammonium sulfate (AMS) on reduced glyphosate rates are well documented; however, these rates are not used by farmers. Studies in 2011 and 2012 determined the effects of AMS and hard water on glyphosate applied at a field rate. AMS (0 or 2.5 L ha−1) and glyphosate (900 g a.e. ha−1) were added to distilled or hard water carriers. Glyphosate plus AMS, in either distilled or hard water, did not usually affect velvetleaf, pigweed species, common ragweed, common lambsquarters and large crabgrass above-ground biomass and density 8 wk after treatment (WAT); however, velvetleaf biomass was reduced with the addition of AMS to glyphosate. Compared with the weedy control 8 WAT, glyphosate plus AMS reduced velvetleaf biomass by 93%, while treatments with no AMS reduced biomass by 77%. In distilled water, 4.8 common lambsquarters plants m−2 remained compared with 7.8 plants m−2 with glyphosate in hard water. For corn yield, an AMS×water hardness interaction was detected; however, no differences were observed among the treatment combinations and the addition of AMS to glyphosate did not affect yield. Therefore, advocating adding AMS to spray solutions containing glyphosate, especially when a labeled rate is used, should be called into question.


Weed Science ◽  
1995 ◽  
Vol 43 (4) ◽  
pp. 541-548 ◽  
Author(s):  
Kurt D. Thelen ◽  
Evelyn P. Jackson ◽  
Donald Penner

Hard-water cations, such as Ca+2and Mg+2, present in the spray solution can greatly reduce the efficacy of glyphosate. These cations potentially compete with the isopropylamine in the formulation for association with the glyphosate anion.14C-Glyphosate absorption by sunflower was reduced in the presence of Ca+2. The addition of ammonium sulfate overcame the observed decrease in14C-glyphosate absorption. Nuclear Magnetic Resonance (NMR) was used to study the chemical effects of calcium and calcium plus ammonium sulfate (AMS) on the glyphosate molecule. Data indicate an association of calcium with both the carboxyl and phosphonate groups on the glyphosate molecule. Initially, a random association of the compounds occurred; however, the reaction progressed to yield a more structured, chelate type complex over time. NH4+from AMS effectively competed with calcium for complexation sites on the glyphosate molecule. Data suggest that the observed calcium antagonism of glyphosate and AMS reversal of the antagonism are chemically based.


2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
G Vogiatzi ◽  
E Oikonomou ◽  
G Lazaros ◽  
M Kostakis ◽  
Z Kypritidou ◽  
...  

Abstract Introduction It has been long investigated the potential role of water quality in cardiovascular health. Purpose The aim of this study was to examine the association between water hardness, arterial stiffness and atheromatic burden in carotid arteries. Design and methods Corinthia study is a cross-sectional epidemiological study conducted in subjects aged 40–99 years. Intima media thickness (IMT) was measured in the left and right common carotid artery, carotid bulb and internal carotid artery. The average of the measurements (mean IMT) and the maximum IMT were determined as the representative value of carotid atherosclerosis burden. Pulse wave velocity (PWV) was used to evaluate arterial stiffness. Tap-water samples were collected from the study area, and analyzed for major, minor and trace elements, as well as pH and total hardness. Results In this analysis we included data from 1.404 participants. In subjects consuming water with a hardness above 250mg/dL, especially in those above &gt;65 years old maximum and mean IMT was significantly increased compared to those consuming water with a hardness above 250mg/dL (1.61mm vs. 1.34mm respectively, p&lt;0.001 and 1.15mm vs. 1.05, p=0.005 for WH ≥250mg/dL and WH &lt;250mg/dL, respectively). Similarly, the prevalence of atheromatic plaques was higher in subjects of the first category (15,2% vs. 7,6%, p=0.004). No differences emerged for the arterial stiffness in the individual subgroups. statistically significant correlation was revealed (p=0.004). Conclusions There seem to be a negative association between extra hard water and carotid atheromatic burden highlighting the possible impact of water quality in cardiovascular health. FUNDunding Acknowledgement Type of funding sources: None. Table 1


Sign in / Sign up

Export Citation Format

Share Document