What is leaching?

What is leaching?

• A. Evaporation
• B. Movement of pesticides through the soil
• C. Adsorption to soil
• D. Degradation

Answer: (B)

Leaching is the downward movement of pesticides through the soil as water drains or percolates, carrying dissolved chemicals with it toward the deeper soil layers or groundwater. This transport happens when rainfall or irrigation supplies enough water to push soluble pesticide molecules down the profile, especially in well-drained or sandy soils. The amount that leaches depends on how soluble the pesticide is and how strongly it adsorbs to soil particles; chemicals with high water solubility and low adsorption are more prone to leaching, while soils rich in organic matter or clays that bind pesticides tend to slow or prevent it. Leaching differs from evaporation (water turning to vapor), adsorption (sticking to soil without moving), and degradation (chemical or microbial breakdown of the pesticide).

Leaching is the downward movement of pesticides through the soil as water drains or percolates, carrying dissolved chemicals with it toward the deeper soil layers or groundwater. This transport happens when rainfall or irrigation supplies enough water to push soluble pesticide molecules down the profile, especially in well-drained or sandy soils. The amount that leaches depends on how soluble the pesticide is and how strongly it adsorbs to soil particles; chemicals with high water solubility and low adsorption are more prone to leaching, while soils rich in organic matter or clays that bind pesticides tend to slow or prevent it. Leaching differs from evaporation (water turning to vapor), adsorption (sticking to soil without moving), and degradation (chemical or microbial breakdown of the pesticide).