The adsorption of a pesticide in soil ____ as its solubility increases.

The adsorption of a pesticide in soil decreases as its solubility increases because of the inherent characteristics of both solubility and adsorption processes. When a pesticide is more soluble in water, it tends to remain in the solution rather than binding to soil particles. This is because solubility allows the pesticide molecules to disperse and move freely within the soil water, reducing their affinity for adsorption sites on soil particles such as clays or organic matter.

A substance with high solubility is less likely to attach itself to the fixed particles in the soil matrix, leading to decreased adsorption. Conversely, pesticides that are less soluble are more likely to adhere to soil particles since they do not have the same tendency to remain in the aqueous phase. Therefore, understanding this relationship is crucial for predicting the behavior of pesticides in the environment, managing their application effectively, and minimizing potential runoff or leaching into water sources.