What is leaching?

What is leaching?

• A. Degradation by sunlight
• B. Evaporation
• C. Movement of pesticides through the soil
• D. Binding to soil particles

Answer: (C)

Leaching is the downward movement of pesticides as water moves through the soil, carrying dissolved chemicals with it. When rain or irrigation wets the soil, some pesticides can dissolve in the water and be pushed deeper into the soil profile, potentially reaching groundwater or non-target soil layers. This process is influenced by how soluble the pesticide is, how strongly it binds to soil organic matter, soil texture (sandy soils drain and allow more movement), and how much water infiltrates the ground. Leaching matters because it can reduce the amount of pesticide available where pests are active and can create environmental risks if contaminants reach groundwater. The other options describe different processes: degradation by sunlight breaks down chemicals on the surface, evaporation involves loss to the air, and binding to soil particles reduces mobility rather than causing it.

Leaching is the downward movement of pesticides as water moves through the soil, carrying dissolved chemicals with it. When rain or irrigation wets the soil, some pesticides can dissolve in the water and be pushed deeper into the soil profile, potentially reaching groundwater or non-target soil layers. This process is influenced by how soluble the pesticide is, how strongly it binds to soil organic matter, soil texture (sandy soils drain and allow more movement), and how much water infiltrates the ground. Leaching matters because it can reduce the amount of pesticide available where pests are active and can create environmental risks if contaminants reach groundwater. The other options describe different processes: degradation by sunlight breaks down chemicals on the surface, evaporation involves loss to the air, and binding to soil particles reduces mobility rather than causing it.