In the past @Olpea and I discussed this very thing about chemical and calcium. Hard water does reduce the effectiveness of chemicals we know that. We also know if you added vinegar to the water your chemicals would effectively become stronger but not better. Adding vinegar is not a good thing but read the attached article and it explains why. This is not unknown to the farming community in our part of the world as chemicals can become very expensive and they want to know they are working properly https://www.croplife.com/crop-inputs/herbicides/herbicide-application-effective-management-of-hard-water-in-spray-solutions/
Ammonium sulfide additions may be added and those impact calcium only but not magnesium and others https://extension.psu.edu/ph-and-water-modifications-to-improve-pesticide-performance
"pH and Water Modifications to Improve Pesticide Performance
The water carrier of pesticides may influence the overall effectiveness of the pesticide used for control. Knowing some basics of water can be useful in protecting yields in crops.
UPDATED: APRIL 19, 2017
I read with interest an article from an Pesticide Education Specialist Reeves Petrof from Montana State University regarding pesticides and water. Here is a brief overview of key points Reeves Petrof details in his fact sheet. I have also added items for the Penn State Vegetable guide as well as the Penn State Water Resources Team.
Pesticides are chemicals and when introduced into water may react depending on the hardness of the water. Cations (+) and anions (-) are similar to magnets. Hard water typically has a positive charge so if a pesticide is an anion or negative charge they will bind together and will not separate once applied to the pest in question. This reduces the effectiveness of the product. A simple water test of your primary spray water supply now will determine how you manage the water this season. Most farms water sample for either dairy, swine and poultry so a water test should be relatively simple to locate and or gain.
Here is a simple table to the hardness of water. Hardness is the makeup of the minerals in the water and may contain either Ca++, Mg+++ or Fe+++
Softbelow 50 ppmMedium Hard50-100 ppmHard100-200 ppmPesticide effects?
I have had several herbicide and insecticide failures that I could not diagnose for certain but I had suspected issues with the water. All of the cases that I was involved in happened to be in spray tanks that were filled and then sat overnight before being emptied and I had theorized a reaction with the water rendered the pesticide useless. One take home message is to avoid allowing certain pesticides to remain in the tank for any long term time frame. One example I was involved with included Dimethoate which can react in literally minutes after mixing pending the water pH. Salt-formulated herbicides such as Roundup (glyphosate), Poast (sethoxydim), Pursuit (imazethapyr), and Liberty (glufosinate) are subject to being bound in the water and for this reason many labels instruct to lower the pH of the water to ensure optimum performance. These minerals may bind with salts of certain herbicides and with some surfactants to form an insoluble salt. These insoluble salts then “fall out" out of solution decreasing herbicide or surfactefficiency. In the case of isopropylamine salt formulations of glyphosate, the positively charged cations of calcium (Ca2+) and magnesium (Mg2+) salts compete with the isopropylamine in the formulation for association with the glyphosate anion (negatively charged). This results in the herbicide having a greater difficulty absorbing into the plant leaf.
In addition, research has shown that extremely hard water, 600 ppm (35 grains/US gallon), can almost completely antagonize 2,4-D amine applied at a low rate of about 4 to 8 ounces per acre. Hard water also affects fungicides and insecticides so it is important to read the labels of all products to determine ideal pH ranges.
Here is a small list of some common products in addition to the glyphosate formulations which is more widely recognized.
Common nameTrade nameHalf-life at different pH valuesFungicide examplesPropiconazoleTiltMost effective in pH 5 to 9; use within 12 to 16 hoursCaptanOrthocidepH 5 = 32 hours, pH 7 = 8 hours, pH 8 = 10 minutesInsecticide examplesCarbarylSevinpH 7 = 24 days, pH 8 = 2.5 days, pH 9 = 1 dayDimethoateCygonpH 4 = 20 hours, pH 6 = 12 hours, pH 9 = 48 minutesPermethrinPounceOptimum stability pH 4Herbicide exampleParaquatGramoxone Extranot stable in pH above 7Plant growth regulatorGibberellic AcidPromalinA buffered wetting, final spray should not exceed pH 8So how do you reduce the hardness of the water?
Note: Acidifiers should not be used in conjunction with some organo-silicone adjuvants as increased acidity may enhance chemical breakdown of the adjuvant. In addition, sulfonyl urea herbicides (Accent, Harmony etc) can degrade in acidic environments below 7.
Read the label!
The most widely used materials to help with hard water is AMS. With the Xtend technologies, it is critical to read the label as additional water modifications can can change the dicamba and change the acid to a more volatile form.
- Ammonium Sulfate (NH4SO4).
Ammonium sulfate (AMS) has been used successfully to increase herbicide efficacy on a broad spectrum of weed species. This is particularly true for the weak-acid herbicides like Roundup (glyphosate), 2-4-D, Pursuit (imazethapyr), Poast (sethoxydim) and Basagran (bentazon). The AMS adjusts the pH so that more of the active herbicide is transported across the leaf surface and into the plant. An added benefit is that sulfate ions (SO4) bind up with hard water minerals. In addition, ammonium-herbicide combinations are more easily absorbed by some weed species. A general rule-of-thumb for adding AMS is the addition of 2% AMS by weight or 17 pounds of dry AMS per 100 gallons of water for most applications.
AMS should be added to the spray carrier solution prior to the herbicide and always, consult the pesticide label for mixing instructions. There may be limitations on the use of fertilizer-based surfactants. The industry has strived to make this process simpler for the applicator by liquifying AMS and there are numerous products that are liquid AMS (Turbo and numerous others) and each product needs to be added at the appropriate rate according to the label to effectively bind the hard water. They can range from a per acre to a per 100 gallon dilution. There are some new products in this arena that either are AMS and or UAN derrivitives. Halo is relatively new the area and has been used to replace AMS, Turbo, Request, Choice, and other similar products.
- Organic Acids.
A very effective treatment is utilizing citric acid. The addition of an organic acid such as food grade citric acid will effectively remove hard water ions from solution. Organic acids are effective because the conjugate base (negative portion) of the acid binds to and removes positively charged cations from solution. A weak acid, such as citric acid, will provide a stronger conjugate base, and therefore, will be more effective than a strong acid such as nitric or hydrochloric acid. The addition of the organic acid will also lower the spray solution pH because of the addition of hydrogen (H+) ions. Organic acid is added to the water carrier prior to the addition of the herbicide. A use rate of 2.2 pounds of citric acid per 100 gallons of water should be adequate for water with 250 ppm of Ca2+.
From my travels, many poultry growers have citric acid on hand for use in the poultry watering system.
- Urea Ammonium Nitrate (UAN)
Some sources of Urea Ammonium Nitrate (UAN) may also reduce the hardness but not as effective as AMS and this is why AMS is preferred over UAN. Some UAN utilizes a Sulfuric Acid source to add Sulfur to the fertilizer mixture and may enhance the acidification from UAN.
Use the following general guidelines once you have determined the pH is of your spray water. Remember, read the pesticide label.
pH 3.5-6.0 Satisfactory for most spraying and short-term (12 to 24 hours) storage of most pesticide mixtures in the spray tank. Read the label. Not suitable for sulfonylurea (Accent, Harmony) herbicides.pH 6.1-7.0 Adequate for immediate spraying of most pesticides. Do not leave the spray mixture in the tank for over 1 to 2 hours to prevent loss of effectiveness.pH 7.0 and higher. Add buffer or acidifier.
You can offset the effects of water pH by adding certain adjuvants (additives) that can either change the pH or your spray mixture or maintain (buffer) the levels of dissolved solids and organic particulate matter … dirt! These soil particles decrease Roundup (glyphosate) and paraquat activity and can cause equipment wear. This type of antagonism cannot be corrected by adding AMS or an organic acid. Always choose a water source that is free of dirt, grit, and organic matter.
Adjuvants and Surfactants
Water softening additives designed for pesticide applications are available to offset hard water problems. While nonionic surfactants will generally enhance herbicide activity on most weed species, they will not overcome the antagonism between salt-based herbicides and hard water. Therefore, under hard water conditions, AMS or organic acids should be used in conjunction with nonionic surfactants to maximize herbicide absorption. Read the label of surfactants that you buy. Some AMS surfactants already have a nonionic surfactant added pH if it already at the desirable level. Here is an older, however useful, fact sheet that UAP has produced with Loveland regarding its LI 700 UAP product that is a penetrant as well as a hard water solution. This product is designed to aid in penetration as well as reduce pH. I am not promoting their product, rather the fact that they have a large list of pesticides and their pH requirements. There are numerous other products similar to this product so check with your supplier for these products and use.
Final ThoughtsThe key is to read the labelGain a water testFill the tank half to 2/3rd full and add the water treatment before adding any of the products that are affected by the pH or hardness.Add other products in the right order to ensure mixing.
By following some simple rules the maximum effectiveness of herbicides, insecticides, fungicides and plant growth regulators may be achieved and avoid failures in the field."
" Herbicide Application: Effective Management of Hard Water in Spray Solutions
By David VincentMay 14, 2019
The Leading Event Where Agriculture Meets Technology
Back in person at the Indiana Convention Center, July 19-21 2022. Act Fast – Early Bird Pricing Available Through May 19!
REGISTER NOW ➔
Water quality is a frequently overlooked factor that can adversely affect the performance of pesticides, especially herbicides. Besides pH, water “hardness” is a key concern, with much of the agricultural water sources across the U.S. exhibiting high concentrations of calcium, magnesium, iron, sodium, and aluminum. These hard-water cations — especially calcium and magnesium — can wreak havoc in a spray tank when not managed.
Weak acid herbicides, such as glyphosate and 2,4-D, are most susceptible, but no herbicide chemistries are completely immune to the negative effects of hard water, including dicamba and sulfonylurea (SU) herbicides. Use of ammonium sulfate (AMS) in spray solutions only counters the effects of calcium hard-water cations, providing no protection whatsoever from magnesium and the others.
Iowa applicator Jason Winegar of Nutrien Ag Solutions has been able to eliminate having to handle and pour 50-pound bags of ammonium sulfate into his sprayer while in the field.
“When you do a good job of addressing hard water, the herbicides mix, blend, and apply much better,” says Jason Winegar, an applicator at Nutrien Ag Solutions in Dunlap, IA. “You get more uniform spray coverage, better adhesion to and penetration of herbicides to target weed species, and more control over drift by better managing spray droplet size and patterns.”
For eight years Winegar has driven floaters and high-clearance sprayers over at least 50,000 acres of corn and soybeans annually. He makes burndown, preemergence, and post-emergence over-the-top herbicide applications and often covers the same ground at least twice during any given growing season.
With a staff of five or six applicators, this Nutrien Ag Solutions location provides custom-application services on at least a quarter-million acres every year. Herbicides routinely applied include glyphosate, Accuron, Diflex, Caprino, Harness Extra, 2,4-D, and dicamba. In addition to his application work, Winegar also works in the company’s mixing and blending facilities.
Multiple Modes of Action
Water with high concentrations of magnesium and calcium is a challenge to manage when applying herbicides. Instead of AMS, Winegar uses a water conditioner, Choice Trio from Loveland Products, which offers three modes of action: sequestering, synthetic chelating, and complexing. The adjuvant, he says, reduces the effects of hard-water cations on herbicide performance, eliminating the need to use AMS.
“We can’t run AMS through the liquid system at the plant because it plugs things up,” Winegar says. “Instead, I have to add it directly to the sprayer while nursing in the field. This means I have to manually open 50-pound bags of granular AMS and pour them into the sprayer. It’s a handling issue that really slows us down when we need to focus on covering as many acres as quickly as possible. We can load the Choice Trio at the plant and do away with the AMS field-loading delays.”
Choice Trio is a liquid formulation available in 2.5-gallon pack sizes. Besides interfering with herbicide efficacy, hard water that isn’t properly buffered also takes its toll on equipment, including pumps, seals, screens, filters, and hoses. “This is another economic downside of hard water,” Winegar says. “It drives up maintenance costs because these items have to be replaced more often.”
Enhanced Grove Care
Commercial applicator Richard Byrd in South Florida makes herbicide applications in an area where water is exceptionally hard. Operating under Richard Byrd Caretaking, he conducts herbicide applications on 1,800 to 2,000 acres of orange groves, making three application trips per year for a combined 5,500 to 6,000 treated acres.
This work includes chemical mowing of grove middles and weed control in the tree line with residual and contact herbicides, including Karmex, Solicam, glyphosate, Tree Vix, and MSO. He uses high-end application equipment, GPS positioning, and other state-of-the-art technology.
“When I’m running flat out, I mix and apply 1,400 to 1,500 gallons of herbicide daily,” Byrd says. “Due to the concentrations of magnesium in the surface water I use as a carrier, I would have to stop two or three times a day — about every 400 to 500 gallons — to clean clogged filters. Then, a few weeks after application, there would be strips in the middles where weeds had not been controlled due to clogged nozzles or herbicide that didn’t mix very well.”
A comparison of filters before and after Choice Trio use.
Another hard-water casualty was the toll it took on spray tanks. A nasty black substance would build up on tank bottoms and walls following herbicide applications. This was residue from the magnesium in the water, and cleaning it required a substantial amount of elbow grease. In 2015 Byrd began using Choice Trio adjuvant to better address the mixing, application, and staining issues associated with hard water.
“I haven’t had to clean the magnesium and chemical residues out of any spray tanks in the four years since I started using the adjuvant,” he says. “I also have greatly reduced — almost eliminated — the downtime associated with clogged filters, screens, and nozzles, as well as the misapplications of herbicides due to mixing issues.”
Byrd says 99.9% of mixtures in the tank are applied and that mixtures stay in suspension longer. “Any herbicide remaining in the tank after application is wasted money,” he notes. “And any herbicides that don’t mix properly are costing you money as well.”
Byrd adds that taming his hard water has had a profound effect on equipment maintenance costs. “I’m getting at least an extra year out of my pump seals, as well as from my pumps,” he says.
Other adjuvants that Byrd routinely relies upon include E-Z Mix when applying powdered or granular herbicides and LI 700 as a sticker/spreader to reduce drift, improve spray droplet retention by adhesion and spreading, and increase herbicide penetration without cuticle disruption. He no longer uses liquid AMS, he says, because he doesn’t have to."
In conclusion calcium sprays should be separate from others. Calcium is a cation which readily bonds to anions neutralizing them. Progressively more soil Scientist and medical
scientist are aware of the importance of these relationships between cations and anions
Cooperative Extension Service
West Lafayette, IN 47907
Fundamentals of Soil Cation Exchange Capacity (CEC)
David B. Mengel, Department of Agronomy, Purdue University
Soils can be thought of as storehouses for plant nutrients. Many nutrients, such as calcium and magnesium, may be supplied to plants solely from reserves held in the soil. Others like potassium are added regularly to soils as fertilizer for the purpose of being withdrawn as needed by crops. The relative ability of soils to store one particular group of nutrients, the cations, is referred to as cation exchange capacity or CEC.
Soils are composed of a mixture of sand, silt, clay and organic matter. Both the clay and organic matter particles have a net negative charge. Thus, these negatively-charged soil particles will attract and hold positively-charged particles, much like the opposite poles of a magnet attract each other. By the same token, they will repel other negatively-charged particles, as like poles of a magnet repel each other.
Forms of Nutrient Elements in Soils
Elements having an electrical charge are called ions. Positively-charged ions are cations; negatively-charged ones are anions.
The most common soil cations (including their chemical symbol and charge) are: calcium (Ca++), magnesium (Mg++), potassium (K+), ammonium (NH4+), hydrogen (H+) and sodium (Na+). Notice that some cations have more than one positive charge.
Common soil anions (with their symbol and charge) include: chlorine (Cl-), nitrate (NO3-), sulfate (S04=) and phosphate (PO43-). Note also that anions can have more than one negative charge and may be combinations of elements with oxygen.
Defining Cation Exchange Capacity
Cations held on the clay and organic matter particles in soils can be replaced by other cations; thus, they are exchangeable . For instance, potassium can be replaced by cations such as calcium or hydrogen, and vice versa.
The total number of cations a soil can hold–or its total negative charge–is the soil’s cation exchange capacity. The higher the CEC, the higher the negative charge and the more cations that can be held.
CEC is measured in millequivalents per 100 grams of soil (meq/100g). A meq is the number of ions which total a specific quantity of electrical charges. In the case of potassium (K+), for example, a meq of K ions is approximately 6 x 1020 positive charges. With calcium, on the other hand, a meq of Ca++ is also 6 x 1020 positive charges, but only 3 x 1020 ions because each Ca ion has two positive charges.
Following are the common soil nutrient cations and the amounts in pounds per acre that equal 1 meq/100g:
Calcium (Ca++) - 400 lb./acre Magnesium (Mg++) - 240 lb./acre Potassium (K+) 780 lb./acre Ammonium (NH4+) - 360 lb./acre
Measuring Cation Exchange Capacity
Since a soil’s CEC comes from the clay and organic matter present, it can be estimated from soil texture and color. Table 1 lists some soil groups based on color and texture, representative soil series in each group, and common CEC value measures on these soils.
Table 1. Normal Range of CEC Values for Common Color/Texture Soil Groups.
CEC in Soil groups Examples meg/100g ----------------------------------------------- Light colored sands Plainfield 3-5 Bloomfield Dark colored sands Maumee 10-20 Gilford Light colored loams and Clermont-Miami 10-20 silt loams Miami Dark colored loams and Sidell 15-25 silt loams Gennesee Dark colored silty clay Pewamo 30-40 loams and silty clays Hoytville Organic soils Carlisle muck 50-100 -------------------------------------------------
Cation exchange capacity is usually measured in soil testing labs by one of two methods. The direct method is to replace the normal mixture of cations on the exchange sites with a single cation such as ammonium (NH4+), to replace that exchangeable NH4+ with another cation, and then to measure the amount of NH4+ exchanged (which was how much the soil had held).
More commonly. the soil testing labs estimate CEC by summing the calcium, magnesium and potassium measured in the soil testing procedure with an estimate of exchangeable hydrogen obtained from the buffer pH. Generally, CEC values arrived at by this summation method will be slightly lower than those obtained by direct measures.
Buffer Capacity and Percent Base Saturation
Cations on the soil’s exchange sites serve as a source of resupply for those in soil water which were removed by plant roots or lost through leaching. The higher the CEC, the more cations which can be supplied. This is called the soil’s buffer capacity .
Cations can be classified as either acidic (acid- forming) or basic. The common acidic cations are hydrogen and aluminum; common basic ones are calcium, magnesium, potassium and sodium. The proportion of acids and bases on the CEC is called the percent base saturation and can be calculated as follows:
Total meq of bases on exchange sites Pct. base =(i.e., meq Ca++ meq Mg++ + meq K+) saturation ------------------------------- x 100 Cation exchange capacity
The concept of base saturation is important, because the relative proportion of acids and bases on the exchange sites determines a soil’s pH. As the number of Ca++ and Mg++ions decreases and the number of H+ and Al+++ions increases, the pH drops. Adding limestone replaces acidic hydrogen and aluminum cations with basic calcium and magnesium cations, which increases the base saturation and raises the pH.
In the case of Midwestern soils, the actual mix of cations found on the exchange sites can vary markedly. On most, however, Ca++ and Mg++ are the dominant basic cations and are in greater concentrations than K+. Normally, very little sodium is found in Midwestern soils.
Relationship Between CEC and Fertilization Practices
Recommended liming and fertilization practices will vary for soils with widely differing cation exchange capacities. For instance, soils having a high CEC and high buffer capacity change pH much more slowly under normal management than low-CEC soils. Therefore, high-CEC soils generally do not need to be limed as frequently as low-CEC soils; but when they do become acid and require liming, higher lime rates are needed to reach optimum pH.
CEC can also influence when and how often nitrogen and potassium fertilizers can be applied. On low-CEC soils (less than 5 meg/20000g), for example, some leaching of cations can occur. Fall applications of ammonium N and potassium on these soils could result in some leaching below the root zone, particularly in the case of sandy soils with low-CEC subsoils. Thus, spring fertilizer application may mean improved production efficiency. Also, multi-year potash applications are not recommended on low-CEC soils.
Higher-CEC soils (greater than 10 meg/100g), on the other hand, experience little cation leaching, thus making fall application of N and K a realistic alternative. Applying potassium for two crops can also be done effectively on these soils. Thus, other factors such as drainage will have a greater effect on the fertility management practices used on high- CEC soils.
The cation exchange capacity of a soil determines the number of positively-charged ions cations-that the soil can hold. This, in turn, can have a significant effect on the fertility management of the soil.
Cooperative Extension work in Agriculture and Home Economics, State of Indiana, Purdue University and U.S. Department of Agriculture cooperating: H.A. Wadsworth, Director, West Lafayette, IN. Issued in furtherance of the acts of May 8 and June 30, 1914. The Cooperative Extension Service of Purdue University is an equal opportunity/equal access institution.