Soil Flashcards
Soil
Slowly renewable resource. Contains nutrients for plant growth
How are soils formed
- Weathering of parent material breaks down rock to form regolith
- Addition of water and decaying /organic material forms true soil. This results in soil layering.
Soil Forming Factors
Parent Material - when soil devs from underlying rock, supply of minerals dependent on parent rock.
Relief/Aspect - direc of slope face. Will affect surface runoff
Climate - Moisture, temp + wind. Most rapid formation is hot + humid places
Organisms - Greater vegetation = greater organic matter = more fertile soils.
Time - Matures soils. Depends on the time taken for the bed rock to be weathered.
Fertile Soil is high in…
Humus
Parent Material of soil contributes to…
Depth
Texture
Drainage
Quality
Soil Particle Size (Descending)
Sand, Silt, Clay
Loam
Soil with sand,silt+clay in = proportions
pH for best growth
5-7
Leaching
Downward removal of soluble material from soil by water
Soil Structures
Granular, singular, columnar, blocky or platy.
Importance of soil
growing plants, construction, mining, preventing
floods and droughts.
Causes of soil erosion
Wind erosion
Water erosion
Overgrazing
Ploughing against contour
Past and present Erosion
Drought
Deforestation
Vulnerable to wind erosion
Recently ploughed fields
Water Erosion
In a thunderstorm each raindrop acts as tiny bomb and displaces soil. Think of splash mass movement
Overgrazing
Vegetation cover removed by animals due to lack of food and erosion occurs
