What factors are critical for the formation of soil structure?

The formation of soil structure is significantly influenced by the presence of shrinking and swelling clays. These clay minerals, particularly expansive clays like montmorillonite, undergo significant volume changes in response to moisture fluctuations. When water is absorbed, these clays expand, and when water is released, they contract. This dynamic movement helps to create and stabilize soil aggregates, which are essential for a well-structured soil.

The ability of clays to swell and shrink also contributes to the development of various soil horizons and porosity, impacting water retention, aeration, and root penetration. As these processes occur over time, they enhance the soil’s overall structure, affecting its physical and chemical properties. The result is a more stable and functional soil environment that supports plant growth and ecological health.

While time and other environmental conditions, such as water saturation, microbial activity, and temperature fluctuations, also play important roles in soil formation and characteristics, the specific impact of shrinking and swelling clays is uniquely critical for the development of soil structure.