CEP Soil Science & Analysis 2

Question 1

Which soil horizon is typically characterized by the accumulation of illuviated clays, iron, and aluminum oxides?

Accepted Answer

B horizon

Answer

The B horizon (subsoil) is the zone of illuviation where materials leached from upper horizons accumulate, including clays, iron, and aluminum oxides.

Question 2

A soil with a cation exchange capacity (CEC) of 40 meq/100g is most likely dominated by which clay mineral?

Accepted Answer

Smectite (montmorillonite)

Answer

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.

Question 3

In the USDA soil texture triangle, which textural class contains approximately 40% sand, 40% silt, and 20% clay?

Accepted Answer

Loam

Answer

Loam is defined as approximately 25–50% sand, 25–50% silt, and 10–25% clay, making the 40/40/20 composition a classic loam.

Question 4

Which process describes the downward movement of dissolved or suspended material through the soil profile?

Accepted Answer

Eluviation

Answer

Eluviation is the process by which water moving through the soil carries dissolved or suspended materials downward out of a horizon.

Question 5

Soil pH of 4.5 would most likely be found in which of the following environmental settings in the United States?

Accepted Answer

Spodosols under coniferous forest in the Northeast

Answer

Spodosols found under coniferous forests in humid northeastern regions are strongly acidic due to organic acid inputs from needle litter and high leaching.

(CEP) Certified Environmental Planner Practice Test

(CEP) Certified Environmental Planner Practice Test

CEP Soil Science & Analysis 2