What soil texture holds pesticides longer?

• A. Clay
• B. Sand
• C. Silt
• D. Gravel

Answer: (A)

Pesticide persistence in soil is largely about how well the soil can sorb or hold onto the chemical. Clay textures have a lot of surface area and many negatively charged sites, which attract and bind many pesticide molecules. That binding makes the pesticides less available for movement or degradation, so they stay in the soil longer. In other words, the more clay in the soil, the greater the retention of pesticides.

Sandy soils, with large particles and little surface area, don’t hold pesticides well; they don’t bind them effectively, so chemicals tend to move through quickly and don’t persist as long. Silt is in between, offering more retention than sand but less than clay. Gravel consists of very large particles with minimal surface area, so it holds very little pesticide and offers almost no retention.

So, the soil texture that holds pesticides longer is the clay texture.