Soil Science and Site Preparation Flashcards

What is finished grade in landscape construction?

Answer: Final elevation of soil after grading and before planting

Finished grade is the final soil elevation after all grading, amending, and shaping is complete, establishing the surface from which planting depths are measured.

What minimum slope away from a foundation is recommended in US residential landscape grading?

Answer: 6 inches drop in the first 10 feet (5 percent grade)

The IRC and most US codes require soil to slope away from foundations at a minimum of 6 inches in the first 10 feet to prevent water from pooling against the structure.

What is subsoil and how should it be handled during landscape grading?

Answer: Infertile soil below topsoil that should not be mixed with topsoil

Subsoil lacks the organic matter and microbial life of topsoil; mixing it into the planting zone dilutes soil quality and it should be stockpiled separately.

What is the purpose of a soil amendment versus a soil fertilizer?

Answer: Amendments improve soil structure; fertilizers add nutrients

Soil amendments physically or chemically change soil properties like structure, pH, or drainage, while fertilizers primarily supply plant nutrients.

Which soil texture is most prone to nutrient leaching because it drains too rapidly?

Answer: Sandy soil

Sandy soil has large particles and pore spaces that allow water and dissolved nutrients to drain rapidly past the root zone before plants can absorb them.

What does N-P-K stand for on a fertilizer label?

Answer: Nitrogen, Phosphorus, Potassium

N-P-K represents nitrogen, phosphorus, and potassium — the three primary macronutrients listed as percentages by weight on every fertilizer label.