What is pesticide leaching?

• A. Movement of pesticides through soil as opposed to movement over the surface.
• B. Movement only on the surface.
• C. Movement through plants.
• D. Degradation in soil.

Answer: (A)

Pesticide leaching is the downward movement of a pesticide through the soil with percolating water, potentially reaching groundwater. This distinguishes it from surface movement, which is runoff that travels across the soil surface rather than moving down through the soil. It’s also not about movement through plants or simply degradation in soil; leaching specifically refers to the downward transport with water. Factors like how soluble the pesticide is, how strongly it adsorbs to soil particles, soil texture and organic matter, and how much and how quickly water moves through the soil all influence leaching. Understanding this helps explain why certain applications risk contaminating groundwater and informs choices about timing, product selection, and application methods to minimize downward movement.