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