Soil Architecture and Physical Properties

These flashcards cover key terms and concepts related to the physical properties of soils, including color, texture, structure, density, and important related processes.

Soil Color

Visual clues about soil properties and conditions; used as a diagnostic criterion for soil classification.

Munsell Color Charts

A standard method for describing the color of dry/wet soil precisely and repeatably.

Hue

The color component that represents the type of color, such as red, yellow, or green.

Value

The lightness or darkness of a color, ranging from 0 (black) to 10 (white).

Chroma

The saturation or intensity of a color; brighter colors have higher numbers.

Soil Texture

The classification of soil based on the size of its particles: sand, silt, and clay.

Soil Bulk Density

The mass of soil per unit volume, including solids and pore spaces, often measured in Mg/m³.

Soil Organic Matter (SOM)

Composed of carbon-based compounds in soil, contributing to soil structure and stability.

Well Sorted Soil

Soil with particles of similar size, resulting in loose packing.

Well Graded Soil

Soil with a range of particle sizes that can fill voids between larger particles, leading to tighter packing.

Clay Flocculation

The process where hydrated cations form bridges between negatively charged clay particles, enhancing stability.

Clay Dispersion

Occurs when monovalent cations, like Na+, prevent clay particles from aggregating, leading to repulsion.

Feel Method

A method to determine soil texture based on moisture content and tactile sensations.

Soil Structure

The arrangement of soil particles and the voids between them, impacting water flow and air movement.

Pore Spaces

The voids within soil that hold air and water; affects soil properties like drainage and aeration.

Granular Structure

Common in the A horizon, characterized by small, crumb-like aggregates.

Prismatic Structure

Found in the B horizon, consisting of columns or blocks that may have angular tops.

Subangular Blocky

A soil structure with irregular, block-like shapes that improve aeration and drainage.

Compaction

The process of increasing soil density, often caused by machinery or heavy traffic, which reduces pore space.

Erosion Susceptibility

The tendency of soil to be worn away by wind or water, influenced by texture and structure.

Decomposition Rate

The speed at which organic matter breaks down in soil, varying with texture.

Texture Triangle

A graphical tool used to classify soil texture based on the relative proportions of sand, silt, and clay.

Soil Organic Matter Stability

The ability of soil aggregates to resist breakdown when wetted, influenced by organic matter content.

Earthworms Impact

Earthworms create biopores that enhance water flow and root growth, contributing to soil health.