Which term describes the downward movement of pesticides and nutrients through the soil?

Which term describes the downward movement of pesticides and nutrients through the soil?

• A. Runoff
• B. Leaching
• C. Transportation
• D. Transformation

Answer: (B)

Downward movement of dissolved substances through the soil happens when water moves down through soil layers and carries soluble pesticides and nutrients with it. This is called leaching. It can push chemicals below the root zone and even toward groundwater, especially when the pesticides are highly soluble and the soil drains quickly. Leaching is driven by how easily a chemical dissolves in water, how strongly it sticks to soil particles (adsorption), the soil’s texture and organic matter content, and how much water moves through the soil from rainfall or irrigation. This differs from runoff, where water and dissolved substances move across the soil surface rather than downward. Transformation refers to chemical or biological changes the pesticide undergoes in the soil, not its movement. Transportation is a more general term and isn’t the specific process described here.

Downward movement of dissolved substances through the soil happens when water moves down through soil layers and carries soluble pesticides and nutrients with it. This is called leaching. It can push chemicals below the root zone and even toward groundwater, especially when the pesticides are highly soluble and the soil drains quickly. Leaching is driven by how easily a chemical dissolves in water, how strongly it sticks to soil particles (adsorption), the soil’s texture and organic matter content, and how much water moves through the soil from rainfall or irrigation.

This differs from runoff, where water and dissolved substances move across the soil surface rather than downward. Transformation refers to chemical or biological changes the pesticide undergoes in the soil, not its movement. Transportation is a more general term and isn’t the specific process described here.