What term describes soils that have no size or grade?

The term that describes soils that have no size or grade is "Structureless." This classification is used when the soil does not exhibit any distinct arrangement of soil particles into aggregates or larger particles, which means it lacks visible structure. Structureless soils do not have naturally occurring peds or clumps that define their physical form; rather, they are typically composed of individual grains that can appear as a homogeneous mass.

In this context, soil structure is essential for understanding water retention, aeration, and root penetration. Structureless soils can often lead to issues with drainage and soil health since they might not support the same biological activity that structured soils do. Understanding the concept of structurelessness is important for soil evaluation, as this characteristic directly impacts soil management practices and agricultural productivity.