10-3 pgs. 255-258

IN: In what climate would you expect to find the best soil?

From Bedrock to Soil 01/8/14

Soil - a loose mixture of small mineral fragments and organic material.

Bedrock - the layer of rock beneath soil.

Soil

Bedrock

Not all soils are the same.

The type of soil depends on the type rock that weathers.

Parent Rock- the rock that is the source of soil is called parent rock.

Humus - very small particles of decayed plant and animal material.

Topsoil – top layer, contains the most humus.

Subsoil – contains clays and dissolved substances.

Bedrock

Partially weathered bedrock from the parent rock.

Leaching – the process by which rainwater dissolves and carries away the minerals and nutrients in topsoil.

Soil also varies because of differences in climate.

Heavy rains cause soil to move.

Tropical topsoil is very thin.

The vegetation growing in the topsoil keeps the heavy rains from eroding it away.

Deserts get very little rain.

Very low rates of chemical weathering leads to very rocky soil.

Sometime chemicals are left behind.Such as salt in Death

Valley.

The most productive soils in the world. Good mix of rain and chemical weathering.

Soil is thin and is unable to support many plants.

Very slow weathering.

OUT: In which type of climate would leaching be more common—tropical or desert? Explain.