Soil Physical Properties Flashcards
Three major factors influence soil color
Organic matter content
Water content
Presence and oxidation state of iron and manganese oxides
Soil colors are described using the _______ color chart, which uses what three color properties?
Mussel
Hue: the specific color
Chroma: intensity or brightness of the color
Value: lightness or darkness
Texture influences many soil properties and behavior such as…
Bulk density Water holding capacity Cation exchange capacity Aeration Erodibility Friability Strength
Primary soil particles are classified as
sand, silt, and clay
Why is surface area so important?
Water retention
Adsorption of gasses and dissolved chemicals
Mineral weathering
Surfaces carry electrical charge,
Contributes to cohesive properties
Nutrient retention
Microorganisms grow on and colonize particle surfaces
Soils are grouped into textural classes such as…
Sandy soils: dominated by sand properties – gritty, good drainage, poor water holding capacity
Clayey soils: dominated by clay properties – heavy, sticky when wet, hard when dry, high water holding capacity
Silty soils: dominated by silt properties – smooth, often weak structure, highly erodible
Loamy soils: mixture of sand, silt and clay
The arrangement of sand, silt, and clay particles to form larger what?
aggregates or peds.
The two types of soil density… and their equations?
Particle Density: mass of solids/volume of solids
DP = MP/VS
Bulk Density: mass of solids/volume of soil
DB = MS/VS
What is porosity? What happens as bulk density increases?
Porosity (PT) is the fraction of total soil volume occupied by voids.
PT = VP/VT
As bulk density increases, porosity decreases
