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SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

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SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL. Soil Genesis. Genesis means origin. It means how soils are developed. Mostly soils are developed by weathering of minerals. Soil genesis includes soil forming factor and soil forming process. - PowerPoint PPT Presentation

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Page 1: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL
Page 2: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL

PROPERTIES OF SOIL

Page 3: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Soil Genesis

Genesis means origin. It means how soils are developed. Mostly soils are developed by weathering of minerals. Soil genesis includes soil forming factor and soil forming process. Soils from mineral materials are developed by the dynamic forces of climate and the action of plants and animals (biosphere) as modified by topography (lay of the land) over time (years).

Page 4: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

I- RESIDUAL PARENT MATERIALS: Parent material formed from weathered

minerals Weathering of bed rocks R.P.M. is formed on relatively level

topographyORIGIN OF PARENT MATERIAL: may be from rocks1. Igneous2. Sedimentary3. Metamorphic rocks—chemical composition

changed by heat

Page 5: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

II- TRANSPORTED PARENT MATERIAL: formed from weathered rocks that have been moved to another location by water, wind, ice or gravity.

III- CUMULOSE PARENT MATERIAL: Could be called residual parent material Because they have been formed in place, in

another sense, they are not residual because they did not develop from underlying bed rocks.

Parent material of organic soils (cummulose) are mostly plant residues preserved by excessive soil wetness.

Page 6: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

SOIL FORMATION FACTORS

A soil is generated when the active factors of climate and biosphere interact with passive parent material and modified by passive topography over neutral time.

Parent material Climate Organisms Topography Time

Page 7: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Soil Forming Processes

Boul et al. (1980). Lists a number of important soil forming processes into four categories i.e. additions, losses, transfers and transformation with in a soil body. Further these are classified as

General processes Specific processes

Page 8: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

General Soil Forming ProcessGeneral Soil Forming Process

• Eluviation:Eluviation: movement of material out (e.g., E movement of material out (e.g., E horizons; also A horizons). horizons; also A horizons). •Illuviation:Illuviation: movement of material in (B horizons) movement of material in (B horizons) •Decalcification:Decalcification: removal of calcium carbonate removal of calcium carbonate •LessivageLessivage: downward migration and accumulation : downward migration and accumulation of clay, producing an of clay, producing an argillicargillic or clay-enriched or clay-enriched horizon.horizon.

Page 9: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Fullerton Series, Typic Hapludult, showing clay, Fe accumlation in the Bt horizon.

Page 10: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Pedoturbation

Pedoturbation is the process of soil mixing by fauna and flora and physical churning and cycling of soil materials. It may invert soil layers. It has following types

• Faunal Pedoturbation• Floral Pedoturbation• Agrilli Pedoturbation

Page 11: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Specific Soil Forming processesSpecific Soil Forming processes

CalcificationCalcification

Weak eluviation and formation of secondary Weak eluviation and formation of secondary calcium carbonates in sub soil horizons and calcium carbonates in sub soil horizons and

leads leads to formation of the chernozemic soils.to formation of the chernozemic soils.

Page 12: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

PPodzolizationodzolization

Fe, Al, and organic matter accumulate in the Fe, Al, and organic matter accumulate in the illuviated spodic (Bh illuviated spodic (Bh or Bs) or Bs)

Fe and Al leach from eluviated albic (E) Fe and Al leach from eluviated albic (E) horizonhorizon

Dominant in the boreal climatic zone,Dominant in the boreal climatic zone, Also occur in southeast coastal plain of US Also occur in southeast coastal plain of US

(Aquods, Groundwater Podzols) an(Aquods, Groundwater Podzols) an ““Giant podzols'' with extremely thick E and Giant podzols'' with extremely thick E and

Bs horizons occur in the tropicsBs horizons occur in the tropics

Page 13: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Other Specific Soil Forming Process

Salination Alkalization Desalination Dealkalization

Page 14: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Photo of soil profile

Spodosol: a result of podzolization (called Podzols in other classification systems besides the US)

Photos courtesy of USDA NRCS, National Survey Centerhttp://www.statlab.iastate.edu/soils/photogal/orders/soiord.htm

Page 15: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

CLIMATE AND SOIL GENESIS

SOIL ORDERS Entisols (any climate, young parent material) Aridisols (dry climate) Histosols (any climate where surface water is abundant) Oxisols (tropical climate) Ultisols (humid, sub-tropical climate) Mollisols & Vertislos (calcareous plant material) Alfisols & Inceptisols (not closely related with climate)

Spodosols

Page 16: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Aridisol Entisol

Photos courtesy of USDA NRCS, National Survey Centerhttp://www.statlab.iastate.edu/soils/photogal/orders/soiord.htm

Page 17: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Gelisol Histosol

Photos courtesy of USDA NRCS, National Survey Centerhttp://www.statlab.iastate.edu/soils/photogal/orders/soiord.htm

Page 18: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Inceptisol Mollisol

Photos courtesy of USDA NRCS, National Survey Centerhttp://www.statlab.iastate.edu/soils/photogal/orders/soiord.htm

Page 19: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Oxisol Spodosol

Photos courtesy of USDA NRCS, National Survey Centerhttp://www.statlab.iastate.edu/soils/photogal/orders/soiord.htm

Page 20: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Ultisol Vertisol

Photos courtesy of USDA NRCS, National Survey Centerhttp://www.statlab.iastate.edu/soils/photogal/orders/soiord.htm

Page 21: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Topography and soil genesis Determines runoff water Controls the amount of soil material

removed and relocated Affects deposition and soil texture Affects the vegetation

Page 22: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Biosphere and soil genesis Flora + Fauna Active Factor Effect of plants Effect of animals

Page 23: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Time and soil genesis Affects soil genesis Neutral Factor Time influences all other factors

Page 24: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Soil Physical Properties

Soil Texture

Provides general information regarding the amount of sand, silt and clay

Soil Structure

Arrangement of soil particles to form aggregates

Page 25: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Soil Physical Properties Soil Consistence

Relative cohesive strength of aggregates to resist rupture and deformation.

Particle densityWeight of individual soil particle in relation to water

Bulk densityWeight of volume of soil in relation to equal volume of water

Page 26: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Soil Physical Properties Soil Color Measured in

terms of hue, value and chroma

Page 27: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Soil Physical Properties

SOIL TEMPERATURE Bacteria (25-30 oC) Fungi (37 oC) N Fixing Organisms (36 oC) Actinomycetes (55-59 oC)

Page 28: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Soil Chemical and colloidal Properties Organic Matter Provides a generalized indication of the

relative fertility status of soil, promotes great water retention, aeration and fertility.

Soil pH An index of the relative acidity and alkalinity of

the soil. Buffering Resistance to change in pH

Page 29: SOIL GENESIS, PHYSICAL, CHEMICAL AND COLLOIDAL PROPERTIES OF SOIL

Soil Chemical and Colloidal Properties

Soil Salinity Range

An index of salt content Cation Exchange Capacity

Relative measure of soil potential to retain added nutrients