Soil Science & Analysis Flashcards
7 cards from real SAF 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
In soil profile description, what does the designation '2Bt' indicate?
Answer: A buried argillic horizon from a different parent material than the horizon above
The '2' prefix indicates a lithologic discontinuity — the Bt horizon formed in a different parent material than the material above it.
Which soil property most strongly controls phosphorus availability in acidic forest soils?
Answer: Iron and aluminum oxide content causing phosphorus fixation
In acidic soils, iron and aluminum oxides strongly adsorb phosphate ions, converting them to insoluble forms unavailable to plants.
A forester measures soil respiration rates before and after a clearcut. What pattern is most commonly observed in the first post-harvest year?
Answer: Respiration rates initially spike due to decomposition of slash and disturbed organic matter, then decline
Harvest slash and disrupted soil organic matter provide a pulse of substrate for decomposers, causing a temporary spike in soil CO₂ efflux.
What is the Munsell color notation system used for in forest soil science?
Answer: Standardized description of soil color using hue, value, and chroma
The Munsell system provides a standardized, reproducible way to describe soil color using three independent dimensions: hue (spectral color), value (lightness), and chroma (saturation).
Which forest floor layer designation (in forest ecology) represents partially decomposed organic material where original plant structures are still recognizable?
Answer: Oe (fermentation layer)
The Oe horizon (formerly called 'F' or fermentation layer) consists of partially decomposed organic material where plant structures remain identifiable.
What is the primary advantage of using tension lysimeters in forest soil studies?
Answer: They collect soil solution under matric tension to sample actual soil water chemistry
Tension lysimeters extract soil solution held at specific matric potentials, enabling analysis of actual nutrient concentrations in water available to plant roots.
On a steep forested hillslope with shallow soils, which factor most increases the risk of shallow landslides following timber harvest?
Answer: Loss of root reinforcement as harvested tree roots decompose over 3-5 years
Harvested tree roots decay over several years, eliminating the mechanical reinforcement they provided to shallow soils on steep slopes before new roots establish.