Landscape Design Soil Science and Site Analysis

Question 1

What are the three primary soil texture classes in the USDA soil texture triangle?

Accepted Answer

Sand, silt, and clay

Answer

The USDA soil texture triangle categorizes soils based on proportions of sand, silt, and clay particles.

Question 2

What does a soil percolation test measure in landscape site analysis?

Accepted Answer

The rate at which water drains through the soil

Answer

A percolation test determines drainage rate by measuring how quickly water infiltrates, guiding decisions about drainage improvements.

Question 3

Which soil amendment is commonly added to heavy clay soil to improve drainage and aeration?

Accepted Answer

Coarse sand or grit, along with organic matter

Answer

Coarse sand improves drainage by increasing pore space, while organic matter improves overall soil structure in clay.

Question 4

What is the purpose of a 'topographic survey' in landscape design site analysis?

Accepted Answer

To map existing grade elevations and slopes across the site

Answer

A topographic survey establishes existing elevation contours that inform grading, drainage, and design decisions.

Question 5

What does a 'soil compaction test' using a penetrometer measure?

Accepted Answer

The resistance of soil to penetration, indicating compaction level

Answer

A penetrometer measures pounds per square inch (psi) of soil resistance, indicating how compacted a soil is.

Landscape Design Practice Test