1. Soil: One of Our Natural Resources
Charity I. Mulig

2. Soil The portion of regolith that can support plant growth.
Inorganic/mineral matter
Humos/organic matter
Air and water
A dynamic interface which responds to changes in the different parts of the earth system

3. Soil Texture refers to the proportions of different particle sizes.
Influences the ease of soil’s cultivation as well as the susceptibility of soil’s erosion; also affects the porosity and permeability of the soil

4. Soil Structure
Describes the way soil forms clumps or peds (platy, prismatic, blocky or spheroidal)
Influences the ease of soil’s cultivation as well as the susceptibility of soil’s erosion; also affects the porosity and permeability of the soil.

5. Controls of Soil Formation

6. Parent Material
Affects the rate of weathering and fertility of the soil
Residual soil the parent material is the underlying bedrock
Transported soil soils develop from unconsolidated sediments; generally form faster than residual soil

7. Time
“the longer the soil has been forming, the thicker it becomes and the less it resembles the parent material”
More time climate has more effect on soil characteristics
Short time parent material has more effect on the soil characteristics

8. Climate The most influential control of soil formation
Influence the type of plant and animal life in the region
Temperature and Precipitation have the greatest effect on soil formation.
Precipitation influences the degree of leaching and therefore the soil fertility.

9. Plants and Animals
Furnish soil with organic matter which aids in water retention
Microorganisms in organic matter also aids in decomposition and nitrogen fixation while burrowing animals mix minerals and humus in the soil.

10. Slope Inclination influences the amount of erosion and water retention
Orientation influences the amount of sunlight
“The optimum terrain for soil development is a flat-to-undulating upland surface.”

11. Soil Profile Soil horizons are zones or layers of soil.
A soil profile is a vertical section through all the soil horizons.

12. Pedalfer (pedon + Al + Fe) Pedocal (pedon + calcite)
Soil Types
Pedalfer (pedon + Al + Fe)
Pedocal (pedon + calcite)
Laterite
Accumulation of iron oxides and aluminum-rich clays in the B horizon
Found in midlatitude areas where there is abundant percipitation.
Soil is brown to reddish brown
Best developed under forest vegetation
Accumulates calcium carbonate
Associated with drier grasslands and brush vegetation
Forms caliche (a calcium-enriched soil)
Forms in hot, wet tropical climates where chemical weathering is intense as well as leaching of soluble minerals such as silica
Removal of silica results to increase concentration of iron and aluminum oxides giving the soil its orange to red color
Poor for growing crops