Which type of soil increases the risk of groundwater contamination due to pesticides?

Sandy soil increases the risk of groundwater contamination due to pesticides primarily because it has larger particle sizes and a coarser texture, which allows water and contaminants to move through it more quickly than in finer-textured soils such as clay or loam. This rapid drainage means that pesticides can leach deeper into the soil profile and potentially reach the groundwater more easily.

Additionally, sandy soils typically have less organic matter and lower nutrient-holding capacity compared to other soil types, which can lead to less binding of pesticides in the soil matrix. As a result, while pesticides may degrade over time due to microbial activity in other soil types, the potential for them to quickly reach groundwater in sandy soils is significantly higher, creating a greater risk of contamination.

In contrast, clay soils, while they can still pose risks, tend to have a lower permeability and can retain contaminants for longer periods, thus reducing the immediate risk of groundwater contamination. Loamy soil is often considered ideal for holding nutrients and moisture, while peaty soil, with its higher organic content, can bind pesticides more effectively, thereby reducing leaching into groundwater.