Which soil texture has the lowest plant-available water?

• A. Loams
• B. Silt
• C. Clay
• D. Sands

Answer: (D)

Plant-available water is the portion of soil moisture roots can use, which depends on how tightly water is bound to soil particles. Soil texture shapes this by creating different pore sizes and drainage patterns.

Sands have large pore spaces and drain quickly, so they don’t hold much water after drainage. The water that remains is minimal in the range roots can easily extract, giving sands the lowest plant-available water.

Loams, silt, and especially clays retain more water in the field-capacity range due to finer textures and stronger capillary forces, so they offer more water that roots can access. While clay can hold a lot of water overall, some is held too tightly, but overall these textures provide more plant-available water than sands.