Ch. 13

• mixture of mineral material, organic matter, air, water, and living organisms • capable of supporting plants growth

• mechanical weathering - physical forces that reduce size of rock particles • chemical weathering - chemical alteration of rock which makes it easier to fragment

• 45% mineral • 25% air • 25% H2O • 5% organic material

facilitates plant growth (taken up by roots)

facilitates plant growth (taken up by roots)

• facilitates aerobic cellular respiration • plant roots need oxygen for this process • CO2 from process + water = carbonic acid • contributes to chemical weathering

• facilitates plant growth (taken up by roots) - food source

0.05 - 2.00 mm

0.002 - 0.05 mm

<0.002 mm

• 40% sand • 40% silt • 20% clay

way in which soil particles clump together

aeration - high water drainage - high mineral holding - low

aeration - good water drainage - good mineral holding - good

aeration - low water drainage - low mineral holding - high

• bacteria, fungi - decomposition of organic material • earthworms (and others) - eat and process soil materials; air pockets • benefit structure by aerating soils

• differ in chemical composition, physical properties, particle size, and amount of organic material • a horizon • c horizon

• top soil - organic and mineral water

weathered parent materal

movement of mineral from top soil layers to bottom soil layers by downward movement of soil water

• amazing with food production • little rainfall • large a horizon (supports plant growth)

• abundant rainfall - small a horizon

• minimal rainfall - small a horizon

• wind, water, and ice wears and transports away soil - occurs where vegetation has been removed