Correcting the Cause

Herbicide Boost

Many post-emergent herbicides must enter the plant cell in order for optimum efficacy. The plant, including weeds, evolve barriers to protect themselves. These waxy layers impede the movement of the herbicide into the plant cell. Often during applications products are added to the herbicide which overcome these barriers and allow the chemical to enter the plant cell. These products, referred to as adjuvants, are often added during tank mixing or formulated with the product. Generally, there are three classes of spray adjuvants used with post-emergent herbicides.

The first class of adjuvants are surfactants. Surfactants are commonly used in corn and soybeans and they allow compounds with two differing solubilities to go into suspension. For simplicity, it is akin to mixing oil and water. Without a surfactant the oil separates from the water. However, with a surfactant the oil is able to suspend in the water.

The second class of adjuvants are crop oil concentrates. Crop oil concentrates are a mixture of a surfactant and a non-phytoxic oil. Crop oil concentrates mode of action is similar to surfactants as they reduce the surface tension and allow the droplets to spread over a larger area and improve coverage.

The final class of adjuvants are nitrogen based fertilizers. Commonly, ammonium sulfate, 28% Urea and 10-34-0 have been used as an adjuvant. Most post-emergent herbicides are weak acids, and at a lower pH these herbicides are able to penetrate the cell membrane. However, when tank mixed with water, the pH of the herbicide becomes more alkaline. The use of ammonium sulfate, urea, and 10-34-0 is successful as an adjuvant because these products lower the pH of the solution to levels which allow the herbicide to penetrate the cell membrane. However, use of these products as an adjuvant has slowed due to the high salt content which can often burn the leaf.

DA-Phos, 7-53-2, has been proven effective as an herbicide adjuvant due to multiple modes of action. Safe for mixing with herbicides, DA-Phos lowers the pH of the tank solution allowing greater herbicide penetration. Along with the increased herbicide efficacy, your crops gain an added boost from the ammoniated nitrogen and clean low salt phosphorus. We can’t say that we are correcting the cause of herbicides, but with DA-Phos we can work to improve their efficiency and therefore reduce the rate and dependency.  A small step that can yield big returns.



PhosRite in Yankton

There are three classes of adjuvants: Surfactants, crop oil concentrates, and nitrogen-based fertilizers.

Herbicide Boost Program

The following are general recommendations for tank mixing DA-Phos as an adjuvant. THESE ARE GENERAL RECOMMENDATIONS it is important to work directly with the Soil Works staff and/or with a trained Soil Works distributor. Every situation is different, please contact us directly to provide you with the optimum program for your operation. Application rates may vary.




2-4 lbs Pure Cane Sugar

2-4 lbs DA-PHOS


  • Product is intended to be applied SPECIFICALLY in the order listed above.
  • Environmental conditions may determine which adjuvant is best suited for maximum efficacy.
  • Be sure to consider tank-mix partners and jar test before application.