Soil: One of Our Natural Resources Charity I. Mulig
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
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
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.
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
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
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.
Plants and Animals • Furnish soil with organic matter which aids in water retention • Microorganisms in organic matter also aids in decomposition and nitrogen fixationwhile burrowing animals mix minerals and humus in the soil.
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.”
Soil Profile • Soil horizons are zones or layers of soil. • A soil profile is a vertical section through all the soil horizons.