soils

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Soils Soils Soils are the result of Soils are the result of weathering weathering Mechanical Mechanical Chemical Chemical Critical resources for Critical resources for food, timber, textiles... food, timber, textiles... Waste filters Waste filters Understanding soils is Understanding soils is important for land-use important for land-use planning, and engineering planning, and engineering

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Soils. Soils are the result of weathering Mechanical Chemical Critical resources for food, timber, textiles... Waste filters Understanding soils is important for land-use planning, and engineering. Idealized soil profile from a humid climate at middle latitudes. Zone of Leaching. - PowerPoint PPT Presentation

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Page 1: Soils

SoilsSoilsSoils are the result of weatheringSoils are the result of weathering

MechanicalMechanical ChemicalChemical

Critical resources for food, timber, Critical resources for food, timber, textiles...textiles...

Waste filtersWaste filters Understanding soils is important for Understanding soils is important for

land-use planning, and engineeringland-use planning, and engineering

Page 2: Soils

Idealized soil profile from a humid climate at middle latitudes

Zon

e of

Lea

chin

g

Page 3: Soils

Horizon Development and Horizon Development and Climate Climate

Page 4: Soils

Soil textural classesSoil textural classes

Page 5: Soils

Topsoil ecosystem Topsoil ecosystem in a temperate in a temperate climateclimate

Page 6: Soils

Porosity and PermeabilityPorosity and Permeability

Water Water saturation saturation and air spaceand air space

Nutrients to Nutrients to plant rootsplant roots

Page 7: Soils

The Water TableThe Water Table

The level The level below which below which the soil is the soil is saturated saturated with water with water (no air space)(no air space)

Page 8: Soils

Soil waterSoil water

Representative Representative water budgetswater budgets

Deficiencies can Deficiencies can be remedied by be remedied by

storage andstorage and irrigationirrigation

Page 9: Soils

Effect of climate on soil developmentEffect of climate on soil development

Page 10: Soils

The Principal Soil TypesThe Principal Soil Types

Page 11: Soils

Effect of climate on soil typesEffect of climate on soil types

tundra soils

Precipitation

Tem

pera

ture

cold

hot hot

coollow high50 cm/yr

pedalferspedocals

laterites

tundra soils

Page 12: Soils

Principal soil types in the USAPrincipal soil types in the USA

Page 13: Soils

Effect of climate on soil typesEffect of climate on soil types

A typical pedocal with A typical pedocal with white white calichecaliche (CaCO (CaCO33) )

deposits in a shallow B deposits in a shallow B horizonhorizon

Page 14: Soils

Effect of climate on soilsEffect of climate on soils

Making Making laterite laterite bricksbricks

Temple at Temple at Angkor Angkor

Wat Wat CambodiaCambodia

(700 yrs (700 yrs old)old)

Laterite

Tundra soil

Page 15: Soils

A Newer A Newer Classification Classification of Soil Typesof Soil Types

Pf

Pc

Pf

Pf, Pc

L

Pf, L

Page 16: Soils

Rates of soil formation:Rates of soil formation:

Central USA: ~ 1 cm/100 years in very porous Central USA: ~ 1 cm/100 years in very porous and permeable rockand permeable rock

Humid N. Carolina: ~ 1 cm/5 yearsHumid N. Carolina: ~ 1 cm/5 years““

Granite may require over 1000 years for a cmGranite may require over 1000 years for a cm

Page 17: Soils
Page 18: Soils

Universal Soil Loss Equation Universal Soil Loss Equation A = RKLSCPA = RKLSCP

A = long-term average annual soil loss for siteA = long-term average annual soil loss for site R = long-term rainfall runoff erosion factorR = long-term rainfall runoff erosion factor K = soil erodibility indexK = soil erodibility index L = hill slope/length factorL = hill slope/length factor S = hill slope gradient (slope) factorS = hill slope gradient (slope) factor C = soil cover factorC = soil cover factor

P = erosion-control practice factorP = erosion-control practice factor

Page 19: Soils

Both Ends of the Erosion ProblemBoth Ends of the Erosion Problem

Serious Serious soil erosionsoil erosion and gully and gully formation related to diversion of formation related to diversion of water runoff over a few months water runoff over a few months in central Californiain central California Sediment pollutionSediment pollution following following

heavy rains in North Carolinaheavy rains in North Carolina

Page 20: Soils

Soil DegradationSoil Degradation ErosionErosion DeforestationDeforestation Agricultural depletionAgricultural depletion Contamination - PollutionContamination - Pollution

SalinizationSalinization PesticidesPesticides Chemical additions and spillsChemical additions and spills

UrbanizationUrbanization DesertificationDesertification OvergrazingOvergrazing

Page 21: Soils

Raindrop impact: Raindrop impact: millions in a single millions in a single shower hit at ~ 30 mphshower hit at ~ 30 mph

Soil ErosionSoil Erosion

Page 22: Soils

Rill-wash and gullying in loose Rill-wash and gullying in loose and poorly-consolidated soilsand poorly-consolidated soils

Soil ErosionSoil Erosion

Page 23: Soils
Page 24: Soils

Soil Lost (tons/km2/yr) % runoffWoods ~ 0 0.12Grass 10 6.5Corn 18087 42Fallow 17050 49

Soil Erosion for Various Uses

Soil ErosionSoil Erosion

Page 25: Soils
Page 26: Soils
Page 27: Soils

Number of dust storms during the month of March, 1936Number of dust storms during the month of March, 1936

Soil ErosionSoil Erosion

Page 28: Soils

Effects of logging in MadagasgarEffects of logging in Madagasgar

Page 29: Soils

Soil ErosionSoil Erosion

Figure 3.12:Figure 3.12: (a) a natural forested slope(a) a natural forested slope(b) the same slope following a clearcut(b) the same slope following a clearcut

Page 30: Soils

Soil ErosionSoil Erosion

Figure 3.12:Figure 3.12: (c) the same slope after conversion to farmland(c) the same slope after conversion to farmland(b) the same slope following urbanization(b) the same slope following urbanization

Page 31: Soils

Soil ErosionSoil Erosion

Page 32: Soils

Soil ErosionSoil Erosion

1968 motorcycles 1968 motorcycles first come to Deer first come to Deer

Creek near Creek near Bakersfield, CABakersfield, CA

1972 after only 4 1972 after only 4 years of ORV use years of ORV use little vegetation or little vegetation or

topsoil remainstopsoil remains

Page 33: Soils

Soil ErosionSoil ErosionORV users increased ORV users increased from 21 to 38 million from 21 to 38 million

between 1982 and 1992between 1982 and 1992

ATVs rip through a marsh in ATVs rip through a marsh in West VirginiaWest Virginia

Great Grizzly Hike, MontanaGreat Grizzly Hike, Montana

Page 34: Soils

Soil ErosionSoil Erosion

1985 photo of bulldozer and jeep tracks in 1985 photo of bulldozer and jeep tracks in Alaskan tundra made in 1946Alaskan tundra made in 1946

Page 35: Soils

Soil ErosionSoil Erosion

Page 36: Soils

Salt accumulation due to irrigation in Salt accumulation due to irrigation in an arid climate: San Fernando Valleyan arid climate: San Fernando Valley

Page 37: Soils

Worldwide Distribution of Salt-affected SoilsWorldwide Distribution of Salt-affected Soils

Page 38: Soils
Page 39: Soils

Chemical Contamination of SoilsChemical Contamination of Soils

Page 40: Soils

Grain production Grain production levels off while levels off while population population continues to growcontinues to grow

Page 41: Soils

Cleaning Up Chemical ContaminationCleaning Up Chemical Contamination

Page 42: Soils

Combating Soil Combating Soil DegradationDegradation

Page 43: Soils

Combating Soil DegradationCombating Soil Degradation

Page 44: Soils

Strip-croppingStrip-croppingand and

Contour plowingContour plowing

Combating Soil DegradationCombating Soil Degradation

Page 45: Soils

Rice terraces in Rice terraces in AsiaAsia

Combating Soil DegradationCombating Soil Degradation

Page 46: Soils

No-tillNo-tillFarmingFarming

Combating Soil DegradationCombating Soil Degradation

Page 47: Soils

Soil Surveys and Adequate Soil Surveys and Adequate PlanningPlanning