Soil Science and Plant Water Requirements Flashcards
7 cards from real CIT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Soil Science and Plant Water Requirements flashcards as text
The effective root depth of cool-season turfgrass used for irrigation scheduling is typically:
Answer: 4 to 6 inches
Cool-season turfgrasses such as Kentucky bluegrass and tall fescue have active root zones of approximately 4 to 6 inches under typical managed conditions.
If the reference ET is 0.25 inches/day and the crop coefficient (Kc) is 0.8, the crop water requirement is:
Answer: 0.20 inches/day
Crop ET equals reference ET multiplied by the crop coefficient: 0.25 × 0.8 = 0.20 inches per day.
A Management Allowable Depletion (MAD) of 50% means irrigation should be triggered when:
Answer: 50% of plant available water has been consumed
MAD of 50% means you irrigate when half of the plant available water — the range between field capacity and wilting point — has been depleted.
Which soil moisture sensor type measures moisture by analyzing electromagnetic wave propagation through the soil?
Answer: TDR/FDR sensor
Time Domain Reflectometry (TDR) and Frequency Domain Reflectometry (FDR) sensors determine volumetric water content by measuring how electromagnetic signals travel through soil.
On the USDA soil texture triangle, a soil with 40% sand, 40% silt, and 20% clay is classified as:
Answer: Loam
A roughly balanced distribution of sand, silt, and moderate clay places this soil squarely in the loam category on the USDA texture triangle.
In a managed turfgrass landscape, which factor most directly determines required irrigation frequency?
Answer: The rate of ET relative to soil water storage capacity in the root zone
Irrigation frequency is primarily determined by how quickly ET depletes the soil water reservoir within the root zone down to the MAD threshold.
Pushing a screwdriver or soil probe into the ground is a simple field method to quickly estimate:
Answer: Soil compaction and moisture level
Easy probe penetration indicates moist, non-compacted soil, while significant resistance indicates dryness or compaction, providing a quick field diagnostic.