what is soil structure

Soil structure refers to the arrangement of the solid parts of the soil and the pore space located between them. It is determined by how individual soil granules clump, bind together, and aggregate, resulting in the arrangement of soil pores between them. Soil structure has a major influence on water and air movement, biological activity, root growth, and seedling emergence. Soil structure is classified by type (shape), class (size) of peds, and grade (strength of cohesion) of aggregates. There are several different types of soil structure, including granular, columnar, and platey. Soil structure is inherently a dynamic and complex system that is affected by different factors such as tillage, wheel traffic, roots, biological activities in soil, rainfall events, wind erosion, shrinking, swelling, freezing, and thawing. Soil aggregation is an important indicator of the workability of the soil, and soils that are well-aggregated are said to have "good soil tilth". Soil structure is important because it allows critical areas of open space, vital for water to move, roots to grow, and soil organisms to thrive.