LARE Soils and Site Conditions Flashcards

According to USDA soil texture classification, which soil type has the highest percentage of sand particles?

Answer: Sandy loam

Sandy loam contains a high proportion of sand (typically 70–85% sand) with smaller amounts of silt and clay, resulting in fast drainage and low water retention.

What does soil 'percolation rate' measure, and why is it important for landscape design?

Answer: The speed at which water moves through the soil, affecting drainage and irrigation design

Percolation rate measures how quickly water moves through the soil, which is critical for sizing bioretention facilities, septic systems, and determining irrigation schedules.

Which USDA natural resources document is the primary reference landscape architects use to obtain detailed soil survey data for a project site in the US?

Answer: Web Soil Survey (WSS) published by NRCS

The USDA-NRCS Web Soil Survey provides county-level soil maps, series descriptions, limitations, and engineering properties for all US project sites.

What does the term 'soil horizon' refer to in site analysis?

Answer: A distinct layer of soil with different physical and chemical properties from adjacent layers

Soil horizons are distinct horizontal layers within the soil profile (O, A, B, C) that differ in color, texture, structure, and composition.

On a LARE site section, which layer is typically shown as 'fill' and why must it be identified?

Answer: Previously placed non-native material that may be unstable or contaminated

Fill is previously deposited non-native material that may be poorly compacted, contain debris or contaminants, and have unpredictable bearing capacity, requiring special design consideration.

What soil property does a 'standard Proctor compaction test' measure, and how is it used in landscape construction?

Answer: Maximum dry density and optimum moisture content for compaction specifications

The Proctor test determines the maximum dry density and optimum moisture content of a soil, which becomes the baseline for compaction specifications in construction documents.