Chapter 12. Chapter 12: Grasslands
What is involved in the formation of soil...?
Guiding Question 12.4
What is involved in the formation of soil and how does land use affect it?
Why You Should Care
Despite its crucial importance to our lives, soil is an often overlooked and underappreciated resource. It is formed of minerals (compounds made of elements like silicon, iron, carbon, and oxygen), organic matter (the decayed remains of organisms, mostly plants), water, and air. The mineral portion of soil is usually the largest and comes from rock as it weathers, or is broken into small particles. Weathering can happen as a result of glaciation, freezing and thawing cycles, pioneer organisms like lichens, chemical reactions with surface water or rain, and so on.
Land used for grazing or raising crops can damage soil or cause it to be lost if either is done too intensively. As previously mentioned, overgrazing can kill grass and lead to destabilization of soil. Overtilling soil for planting crops brings stabile soil to the surface, which allows it to dry out and possibly be carried away by wind or rain. If this degradation is severe enough, the land may be rendered unsuitable for growing crops or raising livestock for decades or longer.
