Soil Management Flashcards
7 cards from real ISA 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 practice best describes 'deep root fertilization'?
Answer: Injecting liquid fertilizer under pressure into the root zone soil
Deep root fertilization uses hydraulic injection to deliver nutrients directly into the root zone, bypassing surface competition.
The 'critical root zone' (CRZ) of a tree is generally calculated as:
Answer: 1 foot radius per inch of trunk diameter at breast height
ISA standards define the CRZ as 1 foot of radius for every inch of trunk DBH, reflecting the radial extent of significant roots.
Phosphorus availability to tree roots is greatest at which soil pH range?
Answer: 6.0–7.0
Phosphorus is most available at slightly acid to neutral pH (6.0–7.0); outside this range it binds with iron, aluminum, or calcium.
Which tillage practice is LEAST damaging to the soil food web around established trees?
Answer: Surface mulching without cultivation
Surface mulching adds organic matter and improves soil biology without physically disrupting fungal networks or fine roots.
A soil with high bulk density is most likely to have:
Answer: Compacted structure with few macropores
High bulk density indicates a dense, compacted soil with fewer pore spaces, limiting root growth and gas exchange.
Sulfur is used as a soil amendment to:
Answer: Lower soil pH in alkaline soils
Soil bacteria oxidize elemental sulfur to sulfuric acid, which reacts with soil carbonates to lower pH over time.
Which statement about soil water is correct?
Answer: Capillary water held at field capacity is the main source for roots
Capillary water retained in micropores after drainage (field capacity) is the primary source of water for tree roots.