Under which soil conditions are pesticides more likely to penetrate?

Pesticides are more likely to penetrate sandy soil with low organic matter due to several key factors. Sandy soil has larger particle sizes, which creates larger pore spaces between soil particles. This structure allows for easier movement of water, air, and other substances, including pesticides, facilitating their downward movement through the soil profile.

In contrast, clay soils, while they may contain organic matter, have very small particles that create a densely packed soil structure with tiny pore spaces. This can hinder water flow and, subsequently, the movement of pesticides. Loamy soil generally provides good drainage and water retention but may still not allow for the same level of penetration as sandy soils, particularly if the organic matter content is high, as this can further reduce the soil's ability to allow easy passage of chemicals.

Sealed pavement surfaces do not allow for any penetration of pesticides at all, as these surfaces are impermeable, preventing any movement of pesticides into the soil beneath.