Formation of Soil SWBAT describe how soil forms; explain the relationship between the organic and inorganic components of soil; identify soil characteristics; recognize soil horizons in a soil profile

Development of Soil Soil Describe the process of soil formation The loose covering of broken rock particles and decaying organic matter Describe the process of soil formation Weathering breaks solid bedrock into smaller pieces These pieces continue to break down Organisms, such as bacteria, fungi, and insects begin to live in the weathered material The organisms die in time, decay, and support a variety of life forms There is a continual process of break down creating nutrients and texture, as well as the ability to hold water (porosity)

Soil Composition Residual soil Transported soil Soil located above its parent material (the rock it was weathered from) Transported soil Soil that has been moved away from its parent bedrock by erosion

Soil Profiles Soil profile Soil horizon The vertical sequence of soil layers Soil horizon A distinct layer or zone within a soil profile Generally 3 distinct horizons Horizon A has concentrated organic matter and humus (top) Horizon B contains subsoils enriched with clay (middle) Horizon C contains contain weathered parent material (bottom)

Topography How does topography affect soil? Affects the thickness of soil In sloped areas, coarser material remains on the slope, while finer particles are pulled downslope due to gravity Soils on slopes tend to be infertile, where lower areas are thick and fertile Direction of the sun also plays a role in soils fertility

Soil Types Polar Temperate Desert Tropical Form at high latitudes. Soils have good drainage but no distinct horizons because they are very shallow due to permafrost Polar Temperate Desert Tropical Able to support diverse environments, such as forests, grasslands, and prairies. They get approximately 50-60 cm of rainfall a year. Receive low levels of precipitation which creates soil that few plants can survive in and weathers easily. These areas experience high temperatures and heavy rainfalls creating highly weathered and infertile soil

Soil Texture and Fertility What are the three classifications for the size of soil? Clay < 0.002 mm Silt 0.002 - 0.05 mm Sand 0.05 – 2 mm What is soil fertility? The measure of how well a soil can support the growth of plants What factors determine a soils color? Its composition and the climate

Get your lab notebook In your groups, complete the problem solving lab on page 172.