Soils

Importance of Soils Plants grow in soils Plants convert solar energy into chemical energy and produce oxygen. Soil provides nutrition to plants. Soils serve as a water filter

What is soil? Soil is a mixture of: Mineral Matter Organic Matter Pore Space

Can we make more soil? Nature is capable of making new soil 500-1,000 years to make 1 new inch of topsoil in optimal conditions. Rate of soil formation is determined by 5 factors.

Parent Material The mineral matter content of soil originates as some form of stone that is eventually broken down. The original parent material impacts the characteristics of the soil.

Climate Temperature Cold Cold Hot HotPrecipitation

Life Life forms that exist under the surface of the soil help begin the process of soil formation Lichens (fungus/algae) Mosses Eventually conditions become favorable for seeds to germinate. Eventually animals become a factor as well

Topography “Lay of the land” Changes in slope and elevation. Impacts availability of moisture. Presence of moisture increases rate of soil formation.

Time Absolute Age Actual years the soils has been developing Actual years the soils has been developing Relative Age Stage of maturity of soil Stage of maturity of soil

Parent Material Rock that has decomposed in place Material that has been deposited Glacial Till (glaciers) Aeolian (wind) Alluvium (streams) Colluvium (gravity) Lacustrine (lakes)

Physical Characteristics of Soil Particle Size Analysis Soil Particles SandSiltClay

Soil Textural Classes Based on percentages of Sand, Silt, Clay

Textural Triangle % Clay% Silt % Sand Point of intersection indicates soil texture

Soil Texture by Particle Analysis 1.25% sand, 25% silt, 50% clay 2.75% sand, 15% silt, 10% clay 3.30% sand, 40% silt, 30% clay 4.15% sand, 15% silt, 70% clay 5.40% sand, 40% silt, 20% clay 6.50% sand, 20% silt, 30% clay 7.2% sand, 81% silt, 17% clay 8.47% sand, 47% silt, 6% clay 9.60% sand, 25% silt, 15% clay 10.10% sand, 60% silt, 30% clay