Sustainability and Soils | Lesson 3 Flashcards
Pedosphere
loose surface of the earth, where the lithosphere interacts with the atmosphere.
Soil formation
- Soil begins to form - disintegrating rock from rain?
- Simple organisms - Organic matter forms on the surface, C horizon forms (bottom layer of the soil)
- Horizon form - Mineral particles form below the organic matter and A horizon forms
- Well developed soil - B horizon forms between A horizon and C horizon
Horizon Layers
O – organic
A – Some mineral, much humus
B – little organic, much mineral
C – weathering bedrock
Inorganic Components
Sand
Perlite
Vermiculite
soil texture
The ratio of sand, silt and clay affects how water moves through the soil. The best mix for agricultural purposes is called a loam.
Hygroscopic
Water clings to the particles making it unavailable to plants
Mostly clay
Capillary
Water held in microbes
Best for plants
Gravitational
Water drains out of the root zone
Mostly sand
Primary Macronutrients
Nitrogen (N), Phosphorus (P), Potassium (K)
Secondary Macronutrients
Calcium (Ca), Magnesium (Mg), Sulfur (S)
Micronutrients
Iron (Fe), Chlorine (Cl), Copper (Cu), Molybdenum (Mo), Zinc, (Zn) Boron (B), Manganese (Mn), Sodium (Na), Cobalt (Co)
Cations
Most nutrients in soil
C HOPKNS CaFe ClZn; CoNa MoB Mn CuMg
Organic Components
Peat and peat moss
Bark or Coir
Organic means the material was once part of a living organism.
CEC
Cation Exchange Capacity
- A clay particle, which is negatively charged, binds cations
- The cations are exchanged for hydrogen ions obtained from carbonic acid (H[2]CO[3]) or from the plant itself
- Mineral cations are released into the soil solution
Mycorrhizae
Fungi that greatly increase the absorptive area of plant roots and help to deliver nitrogen and phosphorus in exchange for sugar.
