Soil Texture and Structure

Abstract

The soil’s composition and texture provide a physical framework and largely determine its capacity to supply water and nutrients and to develop a soil structure resistant to erosion. The finest fractions, having the largest surface area, are the most active. Soil texture, or particle size distribution, is important in various domains, especially influencing response to tillage. Chernozem inherit a loamy texture from the loess parent material but in situ clay formation is characteristic of Calcareous and Common chernozem, whereas degradation of clay by weathering occurs in Podzolized chernozem. Comparison of the particle size and aggregate size distribution reveals the chernozem’s extraordinary capacity for aggregation. According to particle size analysis, silt comprises 60–70% of the soil mass and clay about 15%, but the aggregate size distribution shows almost nothing in these fractions; they are combined into coarser aggregates that lend permeability to air, water and roots, resistance to erosion, and great available water capacity. This soil structure is best developed in pristine chernozem but is remarkably resilient under cultivation.