Effect of Hard Water and Ammonium Sulfate on Weak Acid Herbicide Activity

Carrier water quality may affect the activity of weak acid herbicides when concentrations of some cations are high. A dose-response experiment on glyphosate and imazethapyr activity, which were carried by the carrier types of distilled water and hard water, against jimsonweed were conducted to compare the water conditioning chemicals ammonium sulfate, ammonium nitrate, citric acid and potassium phosphate, with magnetized carrier as a new method. A magnetic field of 0.7 Tesla was applied to prepare the magnetized carrier. With the exception of potassium phosphate with imazethapyr, the activity of glyphosate and imazethapyr was significantly increased in the presence of the water conditioning methods when distilled water was used as the carrier. Ammonium sulfate was the most effective method. The activity of both herbicides was decreased when applied with hard water carrier. Potassium phosphate was not effective at reducing the antagonism of cations in the hard water carrier. In glyphosate, the performance of water conditioning methods in softening hard water carrier could be ranked as follows: ammonium sulfate (2.52-fold) > magnetized carrier (2.12-fold) ≥ citric acid (1.64-fold) ≥ ammonium nitrate (1.39-fold) > potassium phosphate (0.96-fold). In imazethapyr, this order was as follows: ammonium sulfate (2.99-fold) > ammonium nitrate (2.66-fold) > magnetized carrier (1.81-fold) ≥ citric acid (1.64-fold) > potassium phosphate (1.10-fold).

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Weed control by 2,4-D dimethylamine depends on mixture water hardness and adjuvant inclusion but not spray solution storage time

Weed Technology ◽

10.1017/wet.2019.117 ◽

2020 ◽

Vol 34 (1) ◽

pp. 107-116 ◽

Cited By ~ 1

Author(s):

Geoffrey P. Schortgen ◽

Aaron J. Patton

Keyword(s):

Weed Control ◽

Storage Time ◽

Water Hardness ◽

Hard Water ◽

Quality Parameters ◽

Weak Acid ◽

Hardness Level ◽

Spray Solution ◽

Water Conditioning ◽

Acid Herbicides

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.

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The Basis for the Hard-Water Antagonism of Glyphosate Activity

Weed Science ◽

10.1017/s0043174500081613 ◽

1995 ◽

Vol 43 (4) ◽

pp. 541-548 ◽

Cited By ~ 87

Author(s):

Kurt D. Thelen ◽

Evelyn P. Jackson ◽

Donald Penner

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Ammonium Sulfate ◽

Hard Water ◽

Calcium Antagonism ◽

Chemical Effects ◽

Spray Solution ◽

Type Complex ◽

Over Time ◽

Nuclear Magnetic

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.

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AMADS Increases the Efficacy of Glyphosate Formulations on Corn

Weed Technology ◽

10.1614/wt-04-332r3.1 ◽

2006 ◽

Vol 20 (1) ◽

pp. 179-183 ◽

Cited By ~ 1

Author(s):

Dale L. Shaner ◽

Phil Westra ◽

Scott Nissen

Keyword(s):

Growth Inhibition ◽

Ammonium Sulfate ◽

Potassium Salt ◽

Hard Water ◽

Glyphosate Formulations

Greenhouse studies were conducted to determine the effect of 1-aminomethanamide dihydrogen tetraoxosulfate (AMADS) as a spray adjuvant on the efficacy of three different glyphosate formulations, the isopropylamine salt (glyphosate-IPA), potassium salt (glyphosate-K), and the acid of glyphosate dissolved in AMADS (glyphosate-A). All formulations were tested at multiple rates with and without AMADS (2% v/v) on greenhouse-grown corn, and growth inhibition was determined by measuring the elongation of the newest emerging leaf between 1 and 7 d after treatment. AMADS increased the efficacy of all three glyphosate formulations by threefold to fourfold. The IC50 values for glyphosate-IPA, glyphosate-K, and glyphosate-A without AMADS on corn were 77, 54, and 53 g ae/ha, respectively; and with AMADS the values were 20, 18, and 21 g/ha, respectively. AMADS was more effective than ammonium sulfate (2% w/v) in overcoming the antagonism of hard water (200 parts per million Ca+2) on glyphosate-K efficacy on corn. The rainfastness of glyphosate-IPA, glyphosate-A, and glyphosate-K was improved with AMADS.

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

Weed Technology ◽

10.1614/wt-d-16-00040.1 ◽

2016 ◽

Vol 30 (4) ◽

pp. 878-887 ◽

Cited By ~ 3

Author(s):

Pratap Devkota ◽

William G. Johnson

Keyword(s):

Water Quality ◽

Ammonium Sulfate ◽

Linear Trend ◽

Water Hardness ◽

Hard Water ◽

Palmer Amaranth ◽

Weed Species ◽

Hardness Level ◽

Spray Solution ◽

Giant Ragweed

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.

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The Effect of Cations and Ammonium Sulfate on the Efficacy of Dicamba and 2,4-D

Weed Technology ◽

10.1614/wt-d-12-00106.1 ◽

2013 ◽

Vol 27 (1) ◽

pp. 72-77 ◽

Cited By ~ 25

Author(s):

Jared M. Roskamp ◽

Gurinderbir S. Chahal ◽

William G. Johnson

Keyword(s):

Ammonium Sulfate ◽

Divalent Cations ◽

Hard Water ◽

Deionized Water ◽

Weak Acids ◽

Active Ingredients ◽

Common Lambsquarters ◽

Redroot Pigweed ◽

Spray Solution ◽

Herbicide Treatments

Dicamba or 2,4-D will be used POST for the control of weeds in soybean when dicamba- or 2,4-D-resistant soybean are commercialized. The active ingredients of both herbicides are weak acids in solution and may bind to cations present from hard water used as herbicide carrier or from foliar fertilizers added to spray solutions. The objectives of this research were (1) to determine if the efficacy of dicamba or 2,4-D are influenced by divalent cations, namely calcium (Ca), magnesium (Mg), manganese (Mn), and zinc (Zn), in the spray solution, and (2) to determine if adding ammonium sulfate (AMS) to the spray solution can overcome antagonism. The factorial study included five cation solutions (deionized water [dH2O], Ca at 590 mg L−1, Mg at 630 mg L−1, Mn at 4.97 L ha−1, and Zn at 2.33 L ha−1), two herbicide treatments (dicamba or 2,4-D), and two water conditioner treatments (without or with AMS at 20.37 g L−1). Treatments were applied to common lambsquarters, horseweed, and redroot pigweed. Control of horseweed and redroot pigweed increased when AMS was added to the 2,4-D treatments, irrespective of cation solution. Control of common lambsquarters was increased when AMS was added to 2,4-D for only the Ca and Mn cation solution. In contrast to the results obtained with 2,4-D, control of horseweed with dicamba was not influenced by cation solution. Tank-mixing AMS with dicamba increased control of both redroot pigweed and common lambsquarters in the dH2O, Mg, and Mn solutions.

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Divalent Cations in Spray Water Influence 2,4-D Efficacy on Dandelion (Taraxacum officinale) and Broadleaf Plantain (Plantago major)

Weed Technology ◽

10.1614/wt-d-15-00120.1 ◽

2016 ◽

Vol 30 (2) ◽

pp. 431-440 ◽

Cited By ~ 3

Author(s):

Aaron J. Patton ◽

Daniel V. Weisenberger ◽

William G. Johnson

Keyword(s):

Divalent Cations ◽

Hard Water ◽

Plant Size ◽

Weak Acid ◽

Dichlorophenoxyacetic Acid ◽

Plantago Major ◽

Weed Species ◽

Spray Solution ◽

2,4 Dichlorophenoxyacetic Acid ◽

Fertilizer Solutions

2,4-dichlorophenoxyacetic acid (2,4-D) is a common ingredient in POST broadleaf herbicides labeled for use in turf, pastures, rangeland, and grain crops. The herbicide 2,4-D is a weak acid, and when dissociated can bind to cations present in hard-water spray solutions and/or fertilizer solutions. Experiments were conducted with 2,4-D dimethylamine to evaluate the effect of cation solutions on herbicide efficacy on the perennial broadleaf weeds dandelion and broadleaf plantain. The objectives of this research were to (1) determine if 2,4-D efficacy is influenced by the divalent cations, calcium (Ca), magnesium (Mg), manganese (Mn), and zinc (Zn) in spray solution; and (2) determine if adding the adjuvant ammonium sulfate (AMS) to the spray solution can overcome antagonism. Broadleaf plantain and dandelion control was reduced and plant size and mass increased when 2,4-D was applied in a Ca solution in comparison to deionized water. However, 2,4-D antagonism was overcome when AMS was added as an adjuvant to the spray solution. Magnesium caused 2,4-D antagonism on both weed species in one run of the experiment similar to Ca solution and AMS was successful at overcoming antagonism when added to the tank mixture. Some 2,4-D antagonism from Mn was noticed even when AMS was in the tank mix, but Zn fertilizer solutions did not antagonize 2,4-D activity on either weed species. Although divalent cations can antagonize 2,4-D dimethylamine and reduce perennial broadleaf weed control, adding AMS can overcome this antagonism when Ca and Mg are the primary cations in spray solution. Applicators should avoid using Mn fertilizers when applying 2,4-D dimethylamine because AMS did not successfully overcome antagonism.

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The effect of hard water, spray solution storage time, and ammonium sulfate on glyphosate efficacy and yield of glyphosate-resistant corn

Canadian Journal of Plant Science ◽

10.4141/cjps-2014-131 ◽

2014 ◽

Vol 94 (8) ◽

pp. 1401-1405 ◽

Cited By ~ 1

Author(s):

K. J. Mahoney ◽

R. E. Nurse ◽

P. H. Sikkema

Keyword(s):

Ammonium Sulfate ◽

Storage Time ◽

Water Hardness ◽

Hard Water ◽

Corn Yield ◽

Distilled Water ◽

Water Spray ◽

Above Ground Biomass ◽

Common Lambsquarters ◽

Spray Solution

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.

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