CWD Field Survey & Data Collection 2 — Questions and Answers
Question 1: Which tool is most commonly used to collect soil cores during a routine wetland field survey?
- Soil probe or hand auger (Correct answer)
- Backhoe excavation
- PVC core sampler tube
- Shovel with sieve screen
Correct answer: Soil probe or hand auger
A soil probe or hand auger is the standard tool for collecting soil cores in routine wetland determinations because it minimizes disturbance and allows efficient profile examination.
Question 2: When recording Munsell soil color, the notation '10YR 4/2' represents which three components in order?
- Hue 10YR, Value 4, Chroma 2 (Correct answer)
- Value 10, Yellow-Red 4, Chroma 2
- Chroma 10, Hue YR, Value 4/2
- Hue 4, Value 2, Saturation 10YR
Correct answer: Hue 10YR, Value 4, Chroma 2
Munsell notation always lists Hue first (e.g., 10YR), then Value (lightness), then Chroma (color intensity), separated by a slash.
Question 3: In the field, Munsell color readings for hydric soil assessments should be taken under which condition?
- Oven-dried at 105°C for 24 hours
- Air-dried at room temperature
- Moist (field-moist condition) (Correct answer)
- Submerged in distilled water
Correct answer: Moist (field-moist condition)
Munsell colors must be read on moist soil because drying significantly lightens the color and would produce inaccurate chroma and value readings used for hydric soil indicators.
Question 4: Which of the following is a redoximorphic depletion feature used to identify hydric soils?
- Iron-manganese hard concretions
- Gleyed matrix with low chroma gray or greenish colors (Correct answer)
- Mottles with chroma greater than 6
- Dark reddish-brown pore linings
Correct answer: Gleyed matrix with low chroma gray or greenish colors
A gleyed matrix reflects iron reduction and removal under prolonged anaerobic conditions, producing low-chroma gray or blue-green colors that indicate hydric soil conditions.
Question 5: According to Corps of Engineers Regional Supplements, the standard depth to which soil profiles should be examined during a wetland determination is:
- 6 inches
- 12 inches
- 18 inches (Correct answer)
- 36 inches
Correct answer: 18 inches
Regional Supplements generally require soil examination to a depth of at least 18 inches or to a restrictive layer, whichever is shallower, to adequately assess hydric soil indicators.
Question 6: When a soil horizon has both a dominant matrix color and secondary mottles, which is recorded first on the Corps data form?
- The mottle with the highest chroma
- The dominant matrix color (Correct answer)
- The color with the lowest value
- The horizon with the shallowest depth
Correct answer: The dominant matrix color
Data forms require the dominant matrix color to be listed first because it represents the majority of the horizon and is the primary basis for hydric soil indicator assessment.
Question 7: Which hydric soil indicator is identified in the field by a distinctive sulfurous 'rotten egg' odor when the soil is disturbed?
- Histosol or Histic Epipedon
- Iron-Manganese Masses (F12)
- Sulfidic Material (A4) (Correct answer)
- Depleted Matrix (F3)
Correct answer: Sulfidic Material (A4)
Sulfidic Material (Indicator A4) produces hydrogen sulfide gas when disturbed, giving a characteristic rotten egg odor that indicates prolonged anaerobic decomposition of organic matter.
CWD Field Survey & Data Collection 2
Which tool is most commonly used to collect soil cores during a routine wetland field survey?