Which soil type increases the risk of pesticide leaching?

• A. Clay soil
• B. Loamy soil
• C. Sandy soil
• D. Peaty soil

Answer: (C)

Sandy soil increases the risk of pesticide leaching primarily due to its physical characteristics. Sandy soil has larger particle sizes and greater pore spaces, which allow for rapid water movement through the soil. This can lead to quick drainage and reduced retention of pesticides, making them more prone to being washed away with rain or irrigation. Consequently, when pesticides are applied to sandy soils, they can easily leach downwards and potentially contaminate groundwater, especially if the pesticides are highly soluble.

In contrast, clay soils have smaller particles and tighter packing, which typically slows down water movement and helps retain applied substances, including pesticides. Loamy soil, being a balanced mixture of sand, silt, and clay, tends to have moderate drainage and retention capabilities, while peaty soils contain a high organic matter content, which can help bind pesticides and enhance their retention in the soil. Therefore, sandy soil is particularly associated with increased leaching risk compared to these other types.