Soil characteristics and classification Flashcards
How does microbes relate to soil?
Microbes release various acids to break down rocks into small particles.
Microbes nourish the soil by decomposing organic matter and fixing nitrogen.
Well drained soils are high quality with good access of water and oxygen.
How is the soil formed?
Microbes fix carbon and nitrogen -> build-up of organic matter starts.
- > Microbes pave path for lichens -> they grow and die.
- > Formation of organic matter starts.
Nitrogen Cycle as a Biogeochemical Process in Soil?
- Free nitrogen is reduced to ammonia by soil bacteria.
- Ammonia is taken by some plants and microbes to make amino acids, DNA.
- Ammonia is oxidized to nitrites.
- In anaerobic condition,
nitrites and nitrates are
converted back to nitrogen.
Carbon Cycle as a Biogeochemical Process in Soil?
- Carbon is stored as minerals (diamond, charcoal etc.)
- Also in organic form such as proteins.
- Some carbon is temporarily removed from the cycle and stored as coal, methane etc.
Soil particle sizes? From big to small:
Sand (fine rocks)
Silt (fine sand + clay)
Clay (stiff fined grain)
Structure of soil? (from up to bottom)
Two horizons:
Organic upper layer (humus and topsoil).
Underlying rock layers (subsoil, regolith and bedrock).
Example if rain falls into good soil?
- Organisms build structure
- Nutrients are held
- Water is retained and moves slowly thru the soil
= clean water
Example if rain falls into dirt?
- No organism so no structure
- Nutrients move with the water
- Water not help in soil pores
- Leaching, erosion and run-off are problems
= water moves clay, no clean water
Soil Chromatography? Qualitative process.
- Chromatography is used to separate components of a mixture.
- Different components travel through during the stationary phase at different speeds.
- This makes it possible to document the process of separation from one another.
- Soil Chromatography is used to assess the quality of soil in qualitative terms.
Soil Chromatography Result, Central zone:
Minerals are heavy and thus stay in center with low
movement. Heavy minerals means smaller circles.
Soil Chromatography Result, Median zone:
Presence of proteins, organic carbon and matters (minerals and humus).
Soil Chromatography Result, Outer zone:
Clouds at the end of spikes indicate richness of nutrients.
Soil Chromatography Result, Channels:
Greater number of channels suggest increased organic matter and nutrient.
Soil Chromatography Result, Spikes:
Same as channels. Developed spikes means healthy soil with lot of bacterial activity.
Soil Chromatography Result, color:
Warm colors indicate healthy soil. Colder colors represent less microbial activity.
