Which soil type retains water and might block fumigant movement?

Clay is the soil type that retains water and can significantly block fumigant movement. This is because clay particles are very small and densely packed together, leading to a high water retention capacity. The small pore spaces within clay soil create a barrier that impedes the movement of gases, including fumigants. Consequently, fumigants may not disperse evenly or reach intended areas when applied to clay-rich soils, which can reduce their effectiveness in pest control.

In contrast, sand has larger particles and pore spaces, allowing for greater air and gas movement. Silt retains some moisture but does not have the same degree of impediment to gas movement as clay. Loam, being a combination of sand, silt, and clay, offers a balance but still does not exhibit the same high level of water retention and hindrance to fumigant flow as clay does. Therefore, understanding the properties of these soil types is crucial for effective fumigation practices.