Soil Management Flashcards
7 cards from real CCA 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 Management flashcards as text
Which factor most directly controls the rate of organic matter decomposition in soil?
Answer: Soil temperature and moisture
Microbial activity driving decomposition is strongly regulated by temperature and moisture, with optimal rates occurring at warm, moist (but not saturated) conditions.
A soil test reveals high phosphorus but low pH. Which condition most likely explains the reduced P availability?
Answer: P is being fixed by Al and Fe oxides at low pH
At low pH, aluminum and iron oxides become highly reactive and fix phosphorus into insoluble compounds, reducing plant availability.
Which soil texture class has the largest total surface area per unit weight and the highest water-holding capacity?
Answer: Clay
Clay particles have the smallest size and therefore the greatest surface area per unit weight, giving clay soils high water-holding and cation exchange capacity.
What is the term for the process where fine clay particles move downward through the soil profile and accumulate in a lower horizon?
Answer: Illuviation
Illuviation is the process of deposition or accumulation of materials transported from upper horizons into a lower horizon, such as clay forming an argillic horizon.
Which cover crop is most effective at scavenging residual soil nitrate and preventing winter leaching losses?
Answer: Cereal rye
Cereal rye is a non-legume with extensive fibrous roots that rapidly takes up residual nitrate in fall and winter, preventing leaching losses.
Which soil characteristic is most commonly used to identify the boundary between the A and E horizons in a podzolized soil profile?
Answer: Loss of clay, iron, and aluminum
The E (eluvial) horizon is defined by the loss of silicate clay, iron, and aluminum, leaving a lighter-colored, coarser-textured layer below the A horizon.
A field shows wheel-track compaction restricting root growth to the top 6 inches. Which management practice most directly addresses subsoil compaction?
Answer: Subsoiling or deep ripping below the compacted layer
Subsoiling or deep ripping mechanically fractures compacted layers below normal tillage depth, restoring root channels and water infiltration.