Soil Science and Irrigation Flashcards

Which soil test result would indicate the need for lime application in a US landscape project?

Answer: Low pH (highly acidic soil)

Agricultural lime (calcium carbonate) is applied to raise soil pH when soils are too acidic, making nutrients more available to most landscape plants.

What is the purpose of a 'check valve' in a drip irrigation system?

Answer: To prevent water from draining out of the lowest emitters when the system shuts off

Check valves prevent drainage from low-lying emitters when the system is off, avoiding puddling and ensuring more uniform distribution at startup.

What does 'Kc' (crop coefficient) represent in landscape irrigation management?

Answer: A multiplier applied to reference ET to estimate water needs of a specific plant type

The crop coefficient (Kc) adjusts reference evapotranspiration to account for differences in water use between various plant types, landscapes, and growth stages.

What is 'soil structure' and how does it differ from soil texture?

Answer: Soil texture refers to particle size; soil structure refers to how those particles aggregate into clumps

Soil texture describes the proportion of sand, silt, and clay particles, while soil structure describes how those particles clump together into aggregates, affecting drainage and aeration.

Which type of mulch provides the most long-term benefit to soil health as it decomposes?

Answer: Organic mulch such as wood chips or shredded bark

Organic mulches decompose over time, adding organic matter and nutrients to the soil, improving structure, moisture retention, and microbial activity.

What is the primary cause of 'salt injury' to landscape plants in arid western US regions?

Answer: Accumulation of soluble salts from irrigation water or fertilizer in the root zone

Salt injury results from the buildup of dissolved salts in the root zone from irrigation water or excess fertilizer, creating osmotic stress that prevents roots from absorbing water.