Soil Science & Analysis Flashcards
7 cards from real CEP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Soil Science & Analysis flashcards as text
Which soil horizon is typically characterized by the accumulation of illuviated clays, iron, and aluminum oxides?
Answer: B horizon
The B horizon (subsoil) is the zone of illuviation where materials leached from upper horizons accumulate, including clays, iron, and aluminum oxides.
A soil with a cation exchange capacity (CEC) of 40 meq/100g is most likely dominated by which clay mineral?
Answer: Smectite (montmorillonite)
Smectite (montmorillonite) has a very high CEC of 80–150 meq/100g due to its expanding lattice and large surface area, making it the likely dominant clay at 40 meq/100g.
In the USDA soil texture triangle, which textural class contains approximately 40% sand, 40% silt, and 20% clay?
Answer: Loam
Loam is defined as approximately 25–50% sand, 25–50% silt, and 10–25% clay, making the 40/40/20 composition a classic loam.
Which process describes the downward movement of dissolved or suspended material through the soil profile?
Answer: Eluviation
Eluviation is the process by which water moving through the soil carries dissolved or suspended materials downward out of a horizon.
Soil pH of 4.5 would most likely be found in which of the following environmental settings in the United States?
Answer: Spodosols under coniferous forest in the Northeast
Spodosols found under coniferous forests in humid northeastern regions are strongly acidic due to organic acid inputs from needle litter and high leaching.
Which of the following best describes the concept of 'soil structure' in environmental planning contexts?
Answer: The arrangement of soil particles into aggregates or peds
Soil structure refers to the way individual soil particles are arranged and bound together into aggregates (peds), which affects porosity, drainage, and root penetration.
When evaluating a site for a septic system, which soil characteristic is the MOST critical limiting factor?
Answer: Hydraulic conductivity and seasonal high water table depth
Hydraulic conductivity determines how well the soil can absorb effluent, and the seasonal high water table depth determines the minimum safe separation distance to prevent contamination.