SAF Soil Science & Analysis 2

Question 1

Which soil horizon is characterized by the accumulation of leached materials such as clay, iron oxides, and organic matter?

Accepted Answer

B horizon

Answer

The B horizon (subsoil) is the illuvial zone where materials leached from upper horizons accumulate.

Question 2

What does a soil pH of 4.5 indicate about a forest soil's nutrient availability?

Accepted Answer

Likely deficiency of phosphorus and molybdenum with possible aluminum toxicity

Answer

At pH 4.5, phosphorus and molybdenum become unavailable while aluminum and manganese reach toxic levels.

Question 3

In a forest soil with a bulk density of 1.6 g/cm³, which condition is most likely indicated?

Accepted Answer

Compaction or lack of structure

Answer

Bulk density above 1.4-1.5 g/cm³ typically indicates compaction, which restricts root growth and water infiltration.

Question 4

What is the primary function of mycorrhizal fungi in forest soils?

Accepted Answer

Extending effective root surface area for water and nutrient uptake

Answer

Mycorrhizal fungi form symbiotic associations with tree roots, dramatically increasing the absorptive surface area for phosphorus, water, and other nutrients.

Question 5

Which soil texture class has the highest water-holding capacity per unit volume?

Accepted Answer

Silty clay loam

Answer

Fine-textured soils like silty clay loam have abundant small pores that retain water against gravity, giving them the highest water-holding capacity.

(SAF) Society of American Foresters Certification Practice Test

(SAF) Society of American Foresters Certification Practice Test

SAF Soil Science & Analysis 2