Which factors are included in structure designation?

Structure designation in soil science refers to the way soil particles aggregate to form larger units, which is crucial for understanding soil behavior and its various functions. The factors that are included in structure designation are primarily concerned with the characteristics of these soil aggregates, which are evaluated based on their grade, size, and shape.

Grade describes the strength or stability of the aggregates, which can determine how well water and air can move through the soil and how easily roots can penetrate. Size refers to the dimensions of the aggregate clusters, which can range from very small to large formations, impacting the overall porosity and aeration of the soil. Shape pertains to the geometric configuration of these aggregates (such as granular, blocky, or platy), influencing the soil’s ability to drain and hold water.

Understanding these structural traits helps soil evaluators assess the suitability of a soil for various applications, like agriculture or construction, as they influence drainage, erosion potential, and root growth. Thus, grade, size, and shape are integral components that define the structural characteristics of the soil, making this choice the correct answer in the context of structure designation.