FIVE SOIL FORMING FACTORS

WOSSA Training Nov. 2012 Advanced Soil Science Concepts Today’s Subjects: • Review of Soil Basics • Horizontal Groundwater Movement (Soil Physics) • W...
Author: Dominic Osborne
1 downloads 0 Views 3MB Size
WOSSA Training Nov. 2012 Advanced Soil Science Concepts Today’s Subjects: • Review of Soil Basics • Horizontal Groundwater Movement (Soil Physics) • Wicking in Sands and Soil Layering (Capillary Functions) • Hydric (wetland) Soils Development and Regional Indicators

___________________________________ ___________________________________ ___________________________________ ___________________________________

Presenter: Lisa Palazzi, CPSS, PWS J.W. Morrissette & Associates, Inc. www.jwmorrissette.com (previously with Pacific Rim Soil & Water, Inc. www.pacificrimsoilandwater.com) Olympia, WA

___________________________________ ___________________________________ ___________________________________ ___________________________________

FIVE SOIL FORMING FACTORS  Parent Materials (geology)  Climate (weather)  Organisms (living and dead)  Time  Topography

___________________________________ ___________________________________ ___________________________________

The forces of Weather and of Living Organisms, modified by Topography, acting over Time upon Parent Material (Dukochaev, 1883)

___________________________________ ___________________________________ ___________________________________ Basic Soil Profile Development Organic Profile Mineral Profile O horizon: Organic matter accumulation above mineral sediments

A horizon: Zone of organic matter accumulation and incorporation into the mineral soil surface, structured

___________________________________

O??

A

___________________________________

B

___________________________________

O B horizon: Color change, Zone of leachate accumulation (clay and minerals) from above. Structured

B or C?

___________________________________

C horizon: Unweathered, Massive (Structureless) Parent Material

C

___________________________________ ___________________________________ ___________________________________

___________________________________

Soil Forming Processes

___________________________________ ___________________________________ ___________________________________ 4

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

Geology maps

Soil maps

Parent Materials Washington Geology and Soils Maps Terrain or Topography maps

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

Geologic Time Scale and Terminology Eon: Half a billion years + (Biggest) Era: Several hundred million years (Even Bigger) Period: A few hundred million years (Bigger) Epoch: Tens of millions of years (Smallest -- Late and Early) Age: Reported in Millions of Years Ago or MYBP

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

PARENT MATERIAL (prioritize your PM list based on local conditions) 1. CONTINENTAL OR ALPINE GLACIATION (NORTH HALF OF WA STATE) a. Till soils (ice-laid) b. Outwash soils (meltwater deposits) c. Glacio-lacustrine (glacial lakebed sediments) 2. VOLCANIC EVENTS a. Lava flows (HOW OLD?) b. Mudflows (lahars) (HOW OLD?) c. Ash effects 3. BASALT OR GRANITE (IGNEOUS) BEDROCK (HOW OLD?) 4. SEDIMENTARY / METAMORPHIC BEDROCK (HOW OLD?) 5. RECENT ALLUVIUM AND WIND-BLOWN SOILS a. Floodplains b. Loess

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

Glacial Landscape effects • Huge vertical and horizontal weight compacting substrate • Glacial terminus with outwash flood deposits • Dammed glacial lakebeds (next slide)

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

CONTINENTAL GLACIATION IN WASHINGTON, IDAHO AND MONTANA HTTP://HUGEFLOODS.COM/

___________________________________ ___________________________________ ___________________________________

Glacial Lake Columbia (west) and Glacial Lake Missoula (east) are dammed by the Cordilleran Ice Sheet during the Vashon Glaciation (ended about 10,000 ybp). The areas inundated in the Lake Columbia and Lake Missoula floods are shown in gray – the “Channeled Scablands” and extending along Columbia River and Willamette Valley.

___________________________________ ___________________________________ ___________________________________ ___________________________________

GLACIAL TILL SOILS (ICE LAID) A horizon: Surface organic accumulation B horizon: Color change, slight weathering below A

C horizon: Unweathered glacial till

GLACIAL OUTWASH SOILS (WATER LAID) A horizon: Surface organic accumulation B horizon: Color change, slight weathering below A

GLACIAL LAKEBED SEDIMENTS (WATER LAID)

___________________________________

A horizon: Surface organic accumulation B horizon: Color change, slight weathering below A

___________________________________ ___________________________________

C horizon: Unweathered glacial flood deposit C horizon: Unweathered glacial lakebed

Shelton soil, Mason Co.

Everett soils, Pierce Co.

Giles soils, Thurston Co.

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

Volcanic Impacts • PNW volcanoes • Basalt Plains • Granite Intrusions

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

Volcanic Parent Material : Recent Mt. St. Helens Lahar and Ash Deposits

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

___________________________________ VOLCANIC IMPACTS: ASH DEPOSITS

___________________________________ ___________________________________ Volcanic ash deposit over old ash soil profile

___________________________________ ___________________________________ ___________________________________ ___________________________________

VOLCANIC IMPACTS: OLDER MUD FLOWS (LAHARS)

___________________________________ ___________________________________ ___________________________________

Lahar (mudflow) soil (Buckley: ~6000 yrs. old)

___________________________________ ___________________________________ ___________________________________ ___________________________________

RECENT (QUATERNARY TO PRESENT) ALLUVIUM AND WIND-BLOWN SOILS

Floodplains: Recent Alluvial Sediment Deposits

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

___________________________________

RECENT (QUATERNARY TO PRESENT) ALLUVIUM AND WIND-BLOWN SOILS

Palouse Area: Wind-Blown (loess) Sediments

___________________________________ ___________________________________ Lake Missoula Deposits and Erosion

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

CLIMATE Monthly Patterns

___________________________________ ___________________________________ Annual Patterns

___________________________________ ___________________________________ ___________________________________ ___________________________________

ORGANISMS

___________________________________

• PLANTS

 Actinomycetes, Fungi, Algae  Herbs, Grasses  Woody plants (shrubs to trees)  Crops

• ANIMALS

 Microbes  Earthworms  Burrowing animals (moles, gophers, snakes...)  Surface animals (deer, birds, cattle, horses…)  Humans (farms, roads, home sites, cities…)

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

 SLOPE • Erosion, sediment movement, soil

depth • Hydrology (runoff vs. infiltration potential)  ASPECT AND ELEVATION • Temperature (duration of direct sunlight) • Moisture (evaporation) • Vegetation (transpiration)

TOPOGRAPHY Bedrock mountains: steep, shallow soils

___________________________________ ___________________________________

Glacial moraine: rolling terrain, layered, gravelly soils

___________________________________

Floodplain: flat, layered, fine-textured soils

___________________________________ ___________________________________ ___________________________________ ___________________________________

Two Basic Types of Soil Textures/ Profiles

___________________________________

A horizon: Surface organic accumulation B horizon: Color change, slight weathering below A

In between these two extremes are soils with overthickened surface O-horizons overlying mineral soils below.

C horizon: Unweathered Parent material

___________________________________ O horizon: Unusually high content and depth of organic material (a result of slow decomposition in combination with rapid plant growth, usually a result of long-duration saturation)

___________________________________ ___________________________________

Mineral Soil: (mostly sand, silt and clay)

Organic Soil: (composed of rotting leaves, moss, roots…)

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

• BREAK??? ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

Soil Water Movement (Soil Physics)

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

Hydraulic Conductivity: The BIG Picture and the little picture

___________________________________

How water moves through the soil and why you should care. • Saturated flow (gravity driven - down)

• Unsaturated flow (matric potential – i.e. capillary driven – any direction)

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

Water Molecule • Dipolar • Cohesion vs. Adhesion • Surface Tension • Capillary Rise Mechanism

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

___________________________________ ___________________________________ Biggest pores

Solid 50%

Empty Macropores Fill to Sat. Saturated Micropores 25% Water at F.C.

Smallest pores

Soil at Field Capacity

___________________________________ Macropores drain with Gravity Micropores hold water against pull of Gravity (only roots can drain this zone)

Solid 50%

All Soil Pores Full = 100% Saturation

Soil at Saturation

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

Soil Aggregates: The living system = texture + structure + biota + time Impacts on soil drainage 26

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

Granular

___________________________________

Platy Sub-angular Blocky

___________________________________ Prismatic

___________________________________ Columnar (rounded top) 27

___________________________________ ___________________________________ ___________________________________

Water perches at textural and structural changes. Coarse over fine: macro to micropore

Fine over coarse: micro to macropore

Water is “sucked” into fine layer below.

More water is held in finer layer against pull of gravity.

Coarse layer above allows more water through and at a faster rate, until it is slowed at the top of fine layer.

loamy sand

100 % Sat.

sandy loam

Fine layer allows less water through, and at a slower rate; weight of water column will push through at some point.

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

Old Soil Physics video http://www.youtube.com/watch?v=jWwtDKT6NAw&feature=related Watch 2:58-14:10

Surface Tension and Capillarity (fast!) http://www.youtube.com/watch?v=wOOY1szbcX4&feature=related http://www.youtube.com/watch?v=Z0gNOB-v1iI&feature=related http://www.youtube.com/watch?v=HZgeanXiChg Soil texture by hydrometer method (better) http://www.youtube.com/watch?v=XpLIwwX9oyE&feature=related

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

• BREAK??? ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

ADVANCED SOILS SUBJECT AREA: WETLAND (HYDRIC) SOILS Why should a wastewater system designer care about understanding wetlands and/or studying hydric soils – i.e., why don’t we just look for wetland hydrology (or wetland plants)? 1. Because siting a septic system requires awareness of wetland and other water-related setbacks; 2. Because hydric soil morphology indicators help to prove the depth and duration of the water table (even if below 12 inches); 3. Because hydrology is the most ephemeral of the 3 wetland parameters (soils, plants and hydrology); 4. Because Facultative plants, in particular, are highly adaptable; 5. Because liability associated with making the wrong call (wetland or not?) in EITHER direction (too wet or not wet enough) is enormous.

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

WHEN SHOULD YOU ASSESS WETLAND CONDITIONS FOR A SEPTIC PROJECT? Answer: Before anything else…. You can avoid many problems by first defining or delineating (flagging) wetlands or related shallow groundwater conditions.

___________________________________ ___________________________________ ___________________________________ ___________________________________

Ducks!!

Mound septic system

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ How we picture wetlands

___________________________________ ___________________________________ ___________________________________ ___________________________________

___________________________________ How we DON”T picture wetlands

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Two Basic Types of Soil Textures/ Profiles

___________________________________

A horizon: Surface organic accumulation B horizon: Color change, slight weathering below A

In between these two extremes are soils with overthickened surface O-horizons overlying mineral soils below.

C horizon: Unweathered Parent material

___________________________________ O horizon: Unusually high content and depth of organic material (a result of slow decomposition in combination with rapid plant growth, usually a result of long-duration saturation)

___________________________________ ___________________________________

Mineral Soil: (mostly sand, silt and clay)

Organic Soil: (composed of rotting leaves, moss, roots…)

___________________________________ ___________________________________ ___________________________________

Organic Soil Texture Classes •

Based on degree of decomposition of leaves, roots, moss…



A result of chemical and physical weathering of organics



3 textural classes – Peat (fibric – can see what the living plants once were) – Mucky Peat (hemic – halfway decomposed) – Muck (sapric – highly decomposed)



Determining organic soil texture – Visual observation in the field – Send to a lab for OC content test

___________________________________ ___________________________________ ___________________________________ ___________________________________

NOTE: Peat soils can change from fibric to sapric (i.e. muck) within a week or so of being exposed to oxygen

___________________________________ ___________________________________ ___________________________________

Mineral Soil Texture Classes •

___________________________________

Based on particle size distribution (percent sand, silt, clay)



– – •

A result of chemical and physical weathering of rock Physical weathering reduces rock to sand and silt Chemical weathering creates secondary clay minerals 12 soil textural classes (see textural triangle)

• – –

Determining texture Hand Texturing (field) Hydrometer methods (lab)

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

 Hydric soils can be: • Dominantly organic material (~20-100% OM [by wt.] – i.e., peat, muck or mucky peat), • Partly OM (from ~8-20% -i.e., mucky mineral) or • Dominantly mineral material (16 in. of the upper 32 in. is organic* soil • Indicator A2. Histic Epipedon (Taxonomy**)  Surface layer of organic* soil >8 in.

___________________________________ ___________________________________ ___________________________________ ___________________________________

* i.e., Peat, mucky peat, or muck

___________________________________ ___________________________________ ___________________________________ ___________________________________

Indicator A3. Black Histic • Diagnostic layer*: A layer of peat, mucky peat, or muck >8 inches thick;

___________________________________

• Starting at: 6 inches *  Starting at: 60% chroma of 2 inches thickness allowed layer is entirely within the upper 6 in. of the soil ____________________________________

___________________________________



If depleted matrix colors have – values/chromas of 4/1, 4/2, and 5/2, then > 2% redox concentrations (Fe/Mn soft masses and/or pore linings) are required; – other values/chromas (5/1, 6/1, 6/2, 7/1, 7/2, 8/1, 8/2), then no redox concentrations are required.

The low chroma matrix must be caused by wetness and not be a relict or parent material feature – i.e., think – do you have evidence of hydrology and hydrophytic plants?

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________

Definition • Depleted matrix (describes a process): For loamy and clayey material, a depleted matrix refers to the portion of a the diagnostic soil layer where reduction and translocation have removed or transferred iron, thereby creating colors of low chroma (4). NOTE: A, E, and calcic horizons may have low chromas and high values and may be mistaken for a depleted matrix; however, they are excluded from the concept of depleted matrix unless the soil has “common” or “many”, “distinct” or “prominent” redox concentrations occurring as soft masses or pore linings.

___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________



Indicator F6. Redox Dark Surface  Diagnostic layer: >4 inches thick  Located: Entirely