CWD Soil Science & Analysis 2

Question 1

Which soil color matrix notation using the Munsell system indicates the strongest evidence of prolonged saturation?

Accepted Answer

5Y 4/1

Answer

5Y 4/1 has a hue of 5Y and chroma of 1, indicating a gleyed, low-chroma color typical of prolonged anaerobic saturation.

Question 2

In the Corps of Engineers Wetland Delineation Manual, what is the minimum percentage of a soil matrix that must display redoximorphic features to meet the hydric soil criterion under problematic hydric soil indicators?

Accepted Answer

2%

Answer

Some problematic hydric soil indicators, such as F21 (Red Parent Material), require redox concentrations in at least 2% of the matrix.

Question 3

Which process is primarily responsible for the formation of mottles and redox concentrations in hydric soils?

Accepted Answer

Reduction and translocation of iron and manganese

Answer

Alternating reduction and oxidation cycles mobilize iron and manganese, which precipitate as redox concentrations when re-oxidized.

Question 4

A soil pit reveals a dark gray (N 4/) matrix with no other features in the upper 12 inches. Which hydric soil indicator does this BEST match?

Accepted Answer

A4 - Sandy Gleyed Matrix

Answer

Indicator A4 (Sandy Gleyed Matrix) applies to sandy soils with a gleyed matrix (N or 10Y/5GY hues) in the upper 15 cm.

Question 5

When measuring soil organic matter content for hydric soil classification, which laboratory method is considered the standard reference?

Accepted Answer

Walkley-Black wet oxidation

Answer

The Walkley-Black method (wet oxidation with potassium dichromate) is the traditional standard for quantifying soil organic carbon.

(CWD) Certified Wetland Delineator Practice Test

(CWD) Certified Wetland Delineator Practice Test

CWD Soil Science & Analysis 2