Soil Science & Amendments Flashcards

What sand particle size range does the USGA recommend for sports field root zones?

Answer: 0.25–1.0 mm (medium to coarse sand)

USGA specifications recommend sand predominantly in the 0.25–1.0 mm range to balance adequate drainage with structural stability.

Which soil texture classification is generally considered most problematic for natural grass sports fields without significant amendment?

Answer: Clay

Clay soils have poor drainage, high compaction potential, and become very slippery when wet, making them the most problematic for sports fields.

What does the Standard Proctor Test determine?

Answer: Maximum dry density and optimum moisture content for compaction

The Proctor test identifies the optimum moisture content at which a soil achieves its maximum dry density when compacted, which is used to set compaction specifications.

What is the optimal soil pH range for most cool-season turfgrasses used on sports fields?

Answer: 6.0–7.0

Cool-season grasses thrive at pH 6.0–7.0, the range at which macro and micronutrients are most available and soil microbial activity is optimized.

Which amendment is most commonly added to heavy clay subsoils to improve drainage on sports fields?

Answer: Coarse sand

Coarse sand is added to clay soils to increase macropore space, which improves infiltration and drainage rates.

What does Cation Exchange Capacity (CEC) indicate about a soil?

Answer: The soil's ability to retain positively charged nutrient ions

CEC measures the capacity of soil particles to hold and exchange cations such as calcium, magnesium, and potassium, which are essential plant nutrients.

What is the primary purpose of a soil percolation test conducted during sports field site evaluation?

Answer: To measure the rate at which water moves through the soil profile

A percolation test measures how quickly water infiltrates through the soil, which is critical data for designing adequate drainage systems.