CATS Soil and Water 3

Question 1

What is the typical ideal soil pH range for most landscape trees?

Accepted Answer

5.5–7.0

Answer

Most landscape trees thrive in a slightly acidic to neutral pH range of 5.5–7.0, where the majority of nutrients are soluble and available.

Question 2

Which soil texture class has the highest water-holding capacity?

Accepted Answer

Clay soil

Answer

Clay soils have the highest water-holding capacity due to their very small particle size and large surface area, though drainage can be poor.

Question 3

What is the function of mycorrhizal fungi in relation to tree water uptake?

Accepted Answer

They extend the effective root surface area, improving water and nutrient absorption

Answer

Mycorrhizal fungi form symbiotic associations with tree roots, dramatically increasing the absorptive surface area for water and nutrients.

Question 4

How does soil organic matter primarily improve water relations in sandy soils?

Accepted Answer

It increases the soil's water-holding capacity and reduces drainage losses

Answer

Organic matter holds many times its weight in water through hydrogen bonding, significantly improving the water retention of coarse sandy soils.

Question 5

In New Mexico, which soil condition is most likely to cause waterlogged conditions injurious to tree roots?

Accepted Answer

A caliche layer impeding deep drainage

Answer

Caliche (calcium carbonate hardpan) creates an impermeable layer that prevents downward drainage, causing water to pool above it and drown roots.

(CATS) Certified Arborist Tree Service of Albuquerque Practice Test