1. Soil Formation and
Morphology
Basics

2. Processes
Additions
Losses
Translocations
Transformations

3. Pedogenesis:
The process of soil formation as the result
of the combination of soil forming factors
leading to addition, loss, transformation
and translocation of materials

4. Soil Forming Factors

5. Soil Forming Factors
Climate
Organisms
Relief
Parent Material
Time

7. Climate involves both local (microclimatic)
and global (macroclimatic) considerations.
The key components of climate in soil
formation are moisture and temperature.
In general, higher temperatures and rainfall lead to greater soil development. So, we tend to find the most well developed soils in warm, moist environments and the least developed in cool, dry climates. Look at the U.S.
Temperature speeds reactions
Water promotes translocation

8. Organisms
The soil and the organisms living on
and in it comprise an ecosystem.
The active components of the soil
ecosystem are the vegetation, fauna,
including microorganisms, and man.

9. Organisms: Vegetation
Grassland
Forest
Pineland
Vegetation: The primary succession of plants that colonize a weathering rock culminates in the development of a climax community, the species composition of which depends on the climate and parent material, but which, in turn, has a profound influence on the soil that is formed. For example in the Mid-West of the U.S. deciduous forest seems to accelerate soil formation compared to grassland on the same parent material under similar climatic conditions. Differences in the chemical composition of leaf leachates can partly account for a divergent pattern of soil formation. For example acid litter of pines or heather favors the development of acid soils with poor soil structure, whereas litter of decidious trees favors the development of well structured soils.

10. Organisms: Meso-/Macrofauna
Earthworms
Termites
Ants
Beetles
Arthropods
Rabbits
Moles

11. Organisms: microorganisms
Bacteria
Virus
Algae
Fungi
Actinomycetes
protozoa
Microorganisms: The organic matter of the soil is colonized by a variety of soil organisms, most importantly the microorganisms, which derive energy for growth from the oxidative decomposition of complex organic molecules. During decomposition, essential elements are converted form organic combination to simple inorganic forms (mineralization). Most of the microorganisms are concentrated in the top cm of the soil because C substrates are more plentiful there. Estimates of microbial biomass C range from 500 to 2,000 kg /ha to 15-cm depth (White, 1987). Types of microorganisms comprise bacteria, actinomycetes, fungi, algae, protozoa, and soil enzymes

12. Relief/Topography Altitude elevation
climate, vegetation type, potential energy
slope
gradient
overland and subsurface flow, velocity and runoff rate
aspect
slope direction
solar radiation
Relief has also an important influence on the local climate and the vegetation. Changes in elevation affect the temperature (a decrease of approximately 0.5 degree C per 100 m increase in height), the amount and form of the precipitation and the intensity of storm events., thus affecting soil moisture relations. These factors interact to influence the type of vegetation.
Translocation, organic matter, clays, erosion, see above

13. in situ weathering of consolidated rock
Parent Material
in situ weathering of consolidated rock
superficial deposits, which may have been
transported by ice, water, wind or gravity
The nature of the parent material has a decisive effect on the properties of soils. Properties of the parent material that exert a profound influence on soil development include texture, mineralogical composition, and degree of stratification. Soil may form directly by the weathering of consolidated rock in situ (a residual soil), saprolite (weathered rock), or it may develop on superficial deposits, which may have been transported by ice, water, wind or gravity. These deposits originated ultimately from the denudation and geologic erosion of consolidated rock. Consolidated material is not strictly parent material, but serves as a source of parent material after some physical and /or chemical weathering has taken place. Soils may form also on organic sediments (peat, muck) or salts (evaporites). The chemical and mineralogical compositions of parent material determine the effectiveness of the weathering forces. During the early stages of soil formation, rock disintegration may limit the rate and depth of soil development. The downward movement of water is controlled largely by the texture of the parent material. Furthermore, parent material has a marked influence on the type of clay minerals in the soil profile. Leaching Organic matter content Clay translocation Mineral weathering Horizon differentiation Solum thickness
organic sediments

14. Time The value of a soil forming factor may change
Time acts on soil formation in two ways:
The value of a soil forming factor may change
with time (e.g. climatic change, new parent material).
The extent of a pedogenetic reaction depends on the
time for which it has operated.

15. Soil as a Natural Body Differentiation Bedrock Additions Losses
Parent Material
Bedrock
Additions
Losses
Translocations
Parent material is the substrate from which the soil is formed. Over time the soil forming factors (climate, time, relief, organisms, parent material) act in concert to affect a differentiation of the original material into what we describe as soil.
Transformations
Bedrock

16. Soil Horizons
Roughly parallel layers in the soil
with varying composition and properties

17. The Essentials of Soils
Soil Profile – 2D representation of a vertical section of soil from the surface to its deepest layers or horizons.
Soil Profile

18. Soil Horizons

19. Soil Horizons
Roughly parallel layers in the soil
with varying composition and properties

20. Definitions: Eluviation: the loss of materials including clays,
organic matter, oxides of Fe and Al.
Illuviation: accumulation of materials resulting
from eluvial horizons.

21. Master Horizons [
A horizon

22. The A Horizon topsoil/plow layer. A horizon
Accumulates organic material
Often darker than soil below.
high in plant roots, biotic activity
Zone of gas and water exchange
A horizon
A horizon

23. Master Horizons
A horizon
E horizon

24. The E horizon - Zone of Eluviation Elluviation = exit
A horizon
Elluviation = exit
Illuviation = into
E horizon
(Elluvial)
Organic matter
Clay
Carbonates
Fe, Al oxides
color
(Illuvial)

25. Master Horizons
A horizon
E horizon [
B horizon

26. The B Horizon Accumulates material lost from above, or forms in place.
(translocation, transformation)
Zone of Illuviation (translocation).
- Maximum expression of soil development.
clays, O.M., Fe/Al
soil structure
Strong color development
Potentially high reactivity
B horizon

27. Master Horizons
A horizon
E horizon
B horizon [
C horizon

28. The C horizon -Weakly altered by soil forming processes.
-Closely resembles parent
material
C horizon

29. Master Horizons Florida? A horizon E horizon B horizon C horizon

30. The R Horizon
limestone
R horizon

31. O Horizon

32. The O Horizon Surface Horizon Organic horizon
Very high in organic matter
Usually dark-colored
Often called peat, muck
Some are very fertile, valuable
In some countries, O horizon used as fuel.

33. Master Horizons