THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Chapter 2 Formation of Soils from Parent Materials Sampling moon “soil.” (NASA, Apollo 14)

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.1 (a)(b)

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.2

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.3

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey 07458

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey 07458

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Physical Weathering Processes Unloading Temperature –Thermal Expansion –Freeze-Thaw –Frost Wedging Abrasion –Water, Ice, Wind Biological Activity –Burrows –Root Wedging

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Biogeochemical Weathering Processes Hydration –Intact water molecules combine with a mineral 5Fe 2 O 3 + 9H 2 O Fe 10 O 15 (9H 2 O) Hydrolysis –Water Molecule splits into hydrogen and a hydroxyl and the hydrogen replaces a cation from the mineral structure KAlSi 3 O 8 + H 2 O HAlSi 3 O 8 + K + + OH - Dissolution –Aided by small amounts of acid in the water –Soluble ions are retained in the underground water supply CaCO 3 + 2[H + (H 2 )O] Ca 2+ + CO 2 + 3H 2 O OR CaSO 4 (2H 2 O) + 2H 2 O Ca 2+ + SO H 2 O

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Biogeochemical Weathering Processes Carbonation –Weathering is accelerated by the presence of weak acids CO 2 + H 2 O H 2 CO 3 (Carbonic Acid) Then H 2 CO 3 + CaCO 3 Ca HCO 3 - Oxidation-Reduction –Any chemical reaction in which a compound or radical loses electrons –Important in decomposing ferromagnesian minerals 4Fe + 3O 2 2Fe 2 O 3 Or 4Fe (2-) O + O 2 + 2H 2 O 4Fe (3-) OOH (Goethite)

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.5 (a)(b)

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.6 (a)(b)

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Development of Clays The breakdown of parent rock results in the development of clays

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Factors Influencing Soil Formation CLORPT Climate –Primarily precipitation and temperature Organisms –Especially vegetation, microbes, and soil animals Relief –Slope, aspect, and landscape position Parent Material –Geological or organic precursors to the soil Time

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Effects of Parent Material The parent material is what the soil and the nutrients ultimately come from –Examples Colluvium Alluvium Floodplain Glacial Marine Sediments Loess Organic Bogs

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.11

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.12 A productive soil in the Appalachian Mountains formed on colluvium

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.14 Alluvial fans merging into a Bajada in Alaska, which will form well-drained soils

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.13

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.15

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Glacial Erosion

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Glacial Erosion

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.17

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure Till deposits of various kinds 2. Glacial-lacustrine deposits 3. The Loessial blanket 4. Area that escaped glaciation but has loess

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.18

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.19 Glacial Till Glacial Outwash

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.20 Distribution of Dune Sands and Loess Deposits

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Homes carved from Loess deposits in China

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.22 Development of a peat bog resulting in Histosols

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Effects of Climate Effective Precipitation –Depends on timing, topography, and soil type Temperature –Effects the rate of weathering Climate also affects vegetation

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Box 2.1 a. Seasonal Distribution, b. Temperature and Evaporation, c. Topography, d Permeability

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.23 Temperature and Precipitation work together to affect depth of regolith weathered from bedrock

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.24 Climate and Vegetation are interconnected

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Effects of Organisms Flora –Lichen, Moss, Trees Fauna –Mites, Nematodes, Springtales, Earthworms

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.8 The effect of lichen etching bedrock

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.25 Difference in the soil profile under grassland versus forest vegetation

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Change in soil Ph because of forest type

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Semiarid rangeland vegetation will locally enhance fertility, photos from Patagonia Argentina

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.28 Prairie dog burrows help to mix the soil (called crotovinas), photo taken in Illinois

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Effects of Topography Slope and Aspect –Determines amount of solar radiation absorbed Parent Material Interactions –Affects the distribution of colluvium and alluvium Salt Buildup –Arid areas slats are leached from relatively higher areas to lower areas Interaction With Vegetation –Moisture regime is affected by microtopographic changes which in turn controls vegetation distributions

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.29 (a)(b) Topographic influence on soil depth

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.30

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Effects of Time All soil forming processes occur over a very long period of time The time it takes to develop a soil is relative, dependent upon –Climate –Vegetation –Human Interaction

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.31

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey When Everything Else Is Held Equal (Sequences) Catenas –When soils are developed on the same parent material and the soils only differ on the basis of drainage due to variations in relief Chronosequence –A sequence of related soils that differ in certain properties primarily as a result of time as a soil-forming process Lithosequence –A group of related soils that differ as a result of parent material Climosequence –A sequence of soils that differ as a result of changes in climatic regimes (temperature and precipitation) Biosequence –A group of related soils that differ primarily due to variation in kinds and numbers of plants and soil organisms

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Four Basic Processes of Soil Formation Transformation –When soil constituents are chemically or physically modified or destroyed and others are synthesized from precursor materials Translocation –The movement of organic and inorganic materials horizontally or vertically across a pedon Additions –Inputs of materials from outside sources (i.e. plant litter) Losses –Materials that are removed from the soil profile by leaching or erosion

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey Figure 2.32

THE NATURE AND PROPERTIES OF SOILS, 13/e Nyle C. Brady and Ray R. Weil ©2002 Pearson Education, Inc. Upper Saddle River, New Jersey 07458