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What is Soil?. “a living, dynamic system with organic and inorganic components. Soil is a product of its environment and parent material”. components. By volume: 45% mineral 5% organic material 50% space (air/water) By mass? 0% air 18% water 80% mineral 2% organic material.
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“a living, dynamic system with organic and inorganic components. Soil is a product of its environment and parent material”.
components By volume: • 45% mineral • 5% organic material • 50% space (air/water) By mass? • 0% air • 18% water • 80% mineral • 2% organic material
1. The mineral component • inorganic • “mineral”: definition? • Primary: original components of earth crust • Secondary: new minerals made by weathering of earth’s crust • divided by particle size: • Sand, silt, clay
mineral make-up due to: a. Parent Material b. How resistant minerals are c. Climate d. “Age”
a. parent material material on and in which soil develops
Examples of soil developing IN rather than ON parent material: 1. Apostle Islands
Marine deposits:shell, reef and other “bits” formerly at bottom of ocean that have been uplifted
Lacustrine deposits: clay deposits originally laid down at the bottom of a lake; lake is no longer there
Outwash:unconsolidated, sorted material deposited by meltwater from a glacier
Loess:deep deposits of silt that have been deposited by wind
mineral make-up due to: a. Parent Material b. How resistant minerals are c. Climate d. Age
b. resistance of minerals • Soluble minerals are readily LEACHED from soil profile (Ca,Mg,Na) • Certain minerals tend to accumulate in soil • (oxides of Fe, Al, Si)
mineral make-up due to: a. Parent Material b. How resistant minerals are c. Climate d. Age
c. Climate • Amount of leaching • Rate of weathering
mineral make-up due to: a. Parent Material b. How resistant minerals are c. Climate d. Age
d. Age • Parent material is (usually) less influential in “older” (more highly developed) soil
2. Organic Component • Living (primarily decomposers) • Non-living (dead and all in-between stages of decomposition)
…about decomposers: • Nutrient recycling • Respiration
decomposer activity depends on: climate soil moisture conditions Micro-environmental factors (relief, drainage)
decomposers and climate: 1) climate vegetation, litter (amount, type) 2) rate of decomposition hot,wet >> cold, dry
soil moisture conditions • Hot, wet preference of decomposers
micro-environmental factors (relief, drainage) • Slope aspect affects temperature • Drainage affects anaerobic/aerobic decomposition