Under what soil conditions are pesticides more likely to leach through soil?

Pesticides are more likely to leach through soil when they encounter specific conditions that facilitate their movement into groundwater. Sandy soils, which are characterized by larger particle sizes and a generally low capacity to hold moisture, allow for quicker percolation of water. This means that when rainfall or irrigation occurs, water moves rapidly through the sandy layers, transporting any dissolved pesticides along with it.

Low organic matter content in sandy soils diminishes the soil's ability to adsorb chemicals, meaning that pesticides remain in a more mobile state. When groundwater is shallow, any leachate containing pesticides is more likely to reach this water supply, thereby increasing the risk of contamination.

In contrast, clay soils—with their dense, compact structure—tend to retain water and have a higher capacity for holding organic matter, which often binds to pesticides and mitigates leaching. Loamy soils, which typically have a balanced mixture of sand, silt, and clay, also offer better retention and adsorption qualities due to their rich organic content and more stable water table. Heavy compact soils may limit water movement entirely, further preventing leaching.

Thus, the conditions presented in the selected choice accurately reflect the interaction between soil type, organic matter content, and groundwater depth in influencing the leaching