Adjuvants and surfactants used with chemicals

Sunday, November 3, 2013

Making chemical recommendations is always difficult. The terminology is challenging and the chemical names can seem like another language.

A chemical herbicide or pesticide may have many additives to help the chemical work better. These are called adjuvants.

Adjuvants can help facilitate the activity of herbicides or pesticides or they can modify characteristics of the formulation. They are used in many ways. Some of the uses of adjuvants are as wetting agents, penetrants, spreaders, co-solvents, deposit builders (stickers), stabilizing agents or drift controls.

Surfactants are also materials that are added to chemical formulations. Surfactants help facilitate emulsifying, dispersing, spreading or wetting. These two additives can be confusing at first, but they really help make our chemicals more effective.

There are many myths that surround adjuvants and surfactants.

One myth is that they will help soil penetrations. This is false. Only a good soil management program that includes building up of organic matter will help soil penetration.

Another myth that surrounds adjuvants and surfactants is that they will help the plant take up nutrients. To my knowledge, there has not been a study that has shown that adjuvants and surfactants help with plant nutrient uptake.

Usually the homeowner would buy chemicals with the surfactants and the adjuvants already mixed. It is very important to read the label carefully. The products have to be labeled for the particular problem.

Also you need to use the product as directed on the label. Using more or less will affect the working efficiency of the product.

The mantra that more is better doesn't work with chemicals. More chemical isn't any more effective than the right dose; part of that reason has to do with formulation of adjuvants and surfactants.

For large farmers adjuvants and surfactants can be sold as an additive that is added to a tank mix of chemicals. Some of the types of adjuvants that are commonly sold as additives are anti-foaming agents, buffering agents, compatibility agents and liquid fertilizer-herbicide mixtures.

Anti- foaming agents do just that, they help with foam that can be produced by movement of the tank mix. Foam can seriously effect the equipment and the applications thus causing misapplications and time and money wasted.

Buffering agents help keep the tank mixes from getting too acid or basic. Keeping these tank mixes balanced also helps increase the effectiveness of the chemical applications.

Compatibility agents help tank mixes with more than one chemical, such as fertilizer and herbicide, form chemical reactions. These chemical reactions such as precipitation (the settling out of the chemicals in the solution) or the tank mixture heating up can cause problems with the equipment.

Occasionally one of these reactions can cause an explosion or fire, but both are very rare occurrences.

Choice of these adjuvants should be based on the specific needs of the chemical formulation and the crop to which it is going to be applied. The chemicals that are available for tank mixes usually have recommendations on which adjuvants and surfactants can be used with the products. These instructions should be followed completely.

On some occasions a farmer may want to add an anti-drift or anti-foaming adjuvant to the tank. It is wise to contact the manufacturer of the chemical to see if the additive you want to add will cause problems.

Having the right formulation of chemicals, adjuvants, and surfactants can greatly increase your success. It is important to take the adjuvants and surfactants in consideration when purchasing and mixing chemicals.

For more information persons may contact Ann Delchambre at or phone 765-653-8411

Upcoming events

Nov. 11 -- Veterans Day -- Extension office is closed

Nov. 11 -- Utilizing forage workshop -- Clay County Exhibit Hall

Nov. 12 -- CCSI Advanced Cover Crops Workshop -- Pierceton, Ind.

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