In soil classification, what does "textural class" refer to?

The term "textural class" specifically refers to the proportion of sand, silt, and clay particles present in the soil. Soil texture is a fundamental property because it directly influences critical soil functions, including water retention, drainage, fertility, and how well the soil can support plant growth. Each textural class—such as sandy, loamy, or clayey—reflects these proportions and helps in determining the physical behavior of the soil when it interacts with water and plant roots.

While organic matter does contribute to soil health and can influence texture indirectly through aggregation, it is not the main focus when classifying soils into textural classes. Similarly, mineral content is broader and does not specifically address the particle size distribution. Moisture retention capacity is affected by texture but does not define it directly, as this characteristic can vary widely across different texture types based on their proportions of sand, silt, and clay. Thus, the correct answer emphasizes the composition of soil particles, which is foundational to understanding soil behavior and its applications in agriculture and land management.