What is the effect of rainfall on pesticide runoff?

Rainfall has a significant impact on pesticide runoff, primarily increasing the likelihood of pesticides being washed away from the treated area. When heavy rainfall occurs shortly after application, it can lead to an increase in water movement over the soil surface. This movement can physically carry pesticides into nearby waterways, leading to contamination.

Additionally, the intensity and duration of the rainfall play crucial roles in determining the degree of runoff. During a heavy rain event, the volume of water can exceed soil absorption capacity, resulting in greater surface runoff. Furthermore, if the soil is already saturated due to previous rainfall, the potential for runoff increases as the soil cannot hold anymore water.

This underscores the importance of considering weather forecasts and soil conditions when planning pesticide applications to mitigate the risk of environmental contamination due to runoff.