Soil Notes Aim: How does soil form?

I. Soil The end result of weathering, it is a mixture of weathered rocks and organic remains that usually covers bedrock. The nature of the soil depends upon the rocks from which it is weathered and the local climate (average annual temperature and precipitation).

Question # 1 What type of Soil would you expect to find in a desert? Why? Dry, little to no organic matter, thin layers, not well developed.

Question # 2 What type of soil would you expect to find in a rainforest? Why? Very rich soils, thick layers, very moist, lots of organic matter. Weathering of soil produces layers known as soil horizons

Question # 3 If you were to dig a hole in your backyard, describe what happens to the soil as you get deeper. The soil layers change color, usually darker at the top and lighter as you go down. Larger particles are found as you increase in depth. More moisture the further down you go.

II. Soil Horizons Humus- top, organic layer, dark in color and very rich (good for crop growing) A-Plant roots, some organic matter, most weathered soil B-Less weathering occurring, little to no organic matter, leaching of minerals occurs C-Least weathered material, large rocks & boulders Bedrock-impermeable (water can not get into the rocks), solid rock

Soil Horizons Con’t…

Important Soil Terms Residual Soil- when soil remains where it formed Transported Soil- when soil is moved from where it originally formed. Example- Continental Glaciers can pick up and move soils. Leaching- process by which groundwater carries dissolved minerals deeper into the soil as the water infiltrates the ground. Bedrock- the solid layer of rock beneath the soil horizons