Form in structure

Soil structure is how a soil's textural particles - sand, silt, and clay - are arranged into clumps or aggregates. These aggregates are held together by clay and organic matter. Structure gives a soil its form, stability and strength.

Aggregate size and shape, and the network of pores or open spaces between and within the aggregates give a soil its structural form. Good soil structure is important because it improves drainage, infiltration, aeration, root growth and germination.

This diagram below shows how structure can change with depth.

Poorly structured soils often suffer from two common problems: compaction and crusting.

Poorly structured soils often suffer from two common problems: compaction and crusting. An "ideal" soil structure is shown below on the left. On the right is a poorly structured soil with surface crusting and a compacted plow layer. The poorly structured soil also shows changes in aggregates, pore size, and aggregate arrangement.

In intensively managed soils, platy structures can be seen in the plow pan. Platy structures slow the downward movement of water.

In intensively managed soils, platy structures can be seen in the plow pan. Platy structures slow the downward movement of water.

Source: Soil Management Best Management Practice

Available from: www.omafra.gov.on.ca/english/environment/bmp/series.htm


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