Which soil type allows fumigants to move through it more quickly?

Sand is the correct choice because of its larger particle size and structure, which creates larger spaces or pores between the particles. This results in a lower density and allows fumigants to flow through more rapidly compared to other soil types. The increased permeability of sandy soils permits gas exchange and enhances the diffusion of fumigants, making them more effective for pest control.

In contrast, silt and clay have finer particles and smaller pore spaces, resulting in higher water retention and slower movement of gases. Clay, specifically, has very small pores, creating a compact and dense structure that inhibits the movement of fumigants. Loam, which is a mixture of sand, silt, and clay, while better than clay or silt for movement, still does not match the rapid gas transmission capabilities of sandy soils. Therefore, sand allows fumigants to penetrate and disperse more efficiently.