What are adjuvants that adjust the pH of herbicide spray solution called?

Adjuvants that are specifically designed to adjust the pH of herbicide spray solutions are known as buffers. These substances help maintain a stable pH level in the spray solution, which is critical because the efficacy of many herbicides can be significantly affected by the pH. A proper pH level can enhance herbicide activity, improve the compatibility of the mixture, and minimize the likelihood of phytotoxicity or reduced performance.

Buffers work by either releasing or absorbing hydrogen ions in the solution, thus keeping the pH within an optimal range for the herbicide being applied. This is especially important when the water quality used in the mix varies, as different water sources can have different pH levels that could interact with the herbicide's performance.

Other options such as modifiers may alter other physical characteristics of the spray but do not specifically target pH levels. Surfactants improve the wetting and spreading of the solution on plant surfaces, whereas thickeners change the viscosity of the spray mix, but none of these adjuvants serve the primary role of adjusting or stabilizing pH like buffers do. Thus, the role of buffers in herbicide application is vital for ensuring maximum efficacy and safety.