Which type of soil is known to drain the least effectively?

Clay soil is known to drain the least effectively due to its small particle size and compact structure. The tiny particles of clay create very little space between them, which restricts the movement of water through the soil. This leads to poor drainage and can cause water to pool on the surface, as it takes a long time for water to infiltrate clay soil. Additionally, the high plasticity of clay can exacerbate drainage issues, as the soil can swell when wet and shrink when dry.

In contrast, sandy soil has larger particles and allows water to drain rapidly, making it well-draining but less able to retain nutrients. Silty soil retains more moisture than sandy soil but still offers better drainage than clay. Loamy soil, which is a mixture of sand, silt, and clay, strikes a balance between drainage and nutrient retention but still allows for adequate water movement compared to clay soil.