1
Soil compositionSoil compositionSolid space
Pore space
http://www.eoearth.org/article/soil
Conceptual model of distribution of NAPL (nonaqueus-phase liquids in soils. Retention processes include partitioning/
adsorption A) into SOM, B) into soot, C) to SOM surface, D) to mineral/SOM surfaces, and E) into porous minerals
Semple et al. 2004. Defining bioavailability and bioaccessibility of contaminated soil & sediment is complicated. Environ. Sci. Technol. 38: 228A- 231A
National Research Council. 2003. Bioavailability of Contaminants in Soils and Sediments: Processes, Tools, and Applications.
Soil TaxonomySoil Taxonomy
OrderOrder1212
Suborder55
238Great group
238
Subgroup1,243
Family7,504
Series18,80718,807
Little profile development
Entisols**Entisols**
** Major Florida soil
2
Inceptisols*Inceptisols*
Few features
* Minor Florida soil
Distribution of InceptisolsDistribution of Inceptisols
http://soils.usda.gov/technical/classification/orders/inceptisols_map.html
Dry soils
AridisolsAridisols Distribution of Distribution of AridisolsAridisols
Mollisols*Mollisols*Dark soils of grassland
High basesg
Distribution of Distribution of MollisolsMollisols
http://soils.usda.gov/technical/classification/orders/mollisols_map.html
3
Alfisols*Alfisols*Forest soilsMedium-
high baseshigh basesArgillic
horizons (Bt)
Distribution of Distribution of AlfisolsAlfisols
http://soils.usda.gov/technical/classification/orders/alfisols_map.html
Ultisols**Ultisols**
Low bases
Argillic Argillic horizons (Bt)
Distribution of Distribution of UltisolsUltisols
http://soils.usda.gov/technical/classification/orders/ultisols_map.html
Forest soil Low
bases
Spodosols**Spodosols**
bases Spodic
horizons (Bh)
Distribution of Distribution of SpodosolsSpodosols
http://soils.usda.gov/technical/classification/orders/spodosols_map.html
4
Highly weathered
OxisolsOxisols Distribution of Distribution of OxisolsOxisols
http://soils.usda.gov/technical/classification/orders/oxisols_map.html
Peat or bog
> 20% OM
Histosols**Histosols** Distribution of Distribution of HistosolsHistosols
http://soils.usda.gov/technical/classification/orders/histosols_map.html
Ultisols
Entisols
Spodosols
Histosols
Major Florida soil types Major Florida soil types
Oxisols (Oxides)
Entisols** (recent)
Aridisols (dry)
Mollisols* (soft)
Inceptisols* (beginning)
Spodosols** (Bh)
Ultisols** (ultimate)
Alfisols* (mild forest
soil)
Slight StrongWeathering & soil development
5
OxisolMollisol Aridisol Spodosol
1. Soil and its functions2. Soil formation and classification3. Soil physical properties
Review of Basic SoilsReview of Basic Soils
p y p p4. Soil water
5. Soil colloids and pH
6. Soil organisms and organic matter
3. SOIL PHYSICAL PROPERTIES3. SOIL PHYSICAL PROPERTIES
Soil texture Soil structure Soil density
Proportions of different sized particles
Soil textureSoil texture
• Gravel > 2 mm
Soil textureSoil textureRelative amount of sand,
silt, & clay• Gravel > 2 mm
• Sand 0.05-2 mm
• Silt 0.05-0.002 mm
• Clay <0.002 mm or <2 µm
http://en.wikipedia.org/wiki/File:SoilTextureTriangle.jpg
6
Soil StructureSoil Structure
• Arrangement of soil particles in a soil• Aggregate or peds
Bulk densityBulk density
Solid
Pore
1/2
1/4 H2O1/4 air
Bulk densityDb = Wsoil/Vsoil
=1.33 g /1 cm3=1.33 g/cm3
Vsoil =1 cm3, Wsoil=1.33 g
Wsoil= oven dry wt.
Particle densityParticle density
Solid
Pore
1/2
1/4 H2O1/4 air
Particle densityDp = Wsoil/Vsolid
=1.33 g /0.5 cm3=2.66 g/cm3
Vsoil =1 cm3, Wsoil=1.33 g, Vsolid =0.5 cm3
Water potential Water content
4. SOIL WATER4. SOIL WATER
Water movement
Soil WaterSoil Water
Varying availability Soil solution