What is the process called whereby a pesticide adheres to soil particles?

The correct answer is the process known as adsorption. This term refers to the phenomenon where pesticide molecules attach themselves to the surface of soil particles. In this process, the pesticide does not penetrate the soil particles themselves; instead, it forms a bond or is held on the surface due to various physical or chemical interactions. Adsorption influences how long the pesticide remains active in the soil and its availability for uptake by plants or its potential for leaching into groundwater.

In contrast, the term desorption describes the process whereby a substance is released from a surface, releasing the pesticide back into the soil solution. Absorption, however, refers to the incorporation of a substance into the volume of another material; in this case, it would imply that the pesticide is taken up and integrated within the soil particles. Filtration pertains to the separation of particles or substances from a liquid through a porous barrier, which is not relevant to the adherence of pesticides to soil. Understanding these terms allows for a better grasp of pesticide behavior in the environment and informs effective application practices.