Soil Science & Analysis Flashcards
7 cards from real GAP 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 & Analysis flashcards as text
A soil test reports a cation exchange capacity (CEC) of 5 meq/100g. This soil is best described as:
Answer: Sandy with low nutrient-holding capacity
A CEC of 5 meq/100g indicates a coarse, sandy soil with limited ability to retain cations like calcium, magnesium, and potassium.
Which nutrient is most commonly tied up and unavailable to plants when soil pH drops below 5.5?
Answer: Phosphorus
Phosphorus becomes fixed by iron and aluminum compounds in acidic soils below pH 5.5, making it largely unavailable to plants.
What does a high electrical conductivity (EC) reading in a soil test indicate?
Answer: Excessive soluble salts that may harm crops
High EC indicates excessive soluble salts in the soil, which can cause osmotic stress, reducing water uptake and crop yields.
In the context of GAP, why is it important to test soil for heavy metals before growing fresh produce?
Answer: Contaminated soil can transfer heavy metals to edible crops, posing food safety risks
Heavy metals like lead, cadmium, and arsenic can accumulate in produce grown in contaminated soil and pose serious health risks to consumers.
Which soil texture has the best balance of drainage and water-holding capacity for most vegetable crops?
Answer: Silt loam
Silt loam provides a good balance of pore sizes, allowing adequate drainage while retaining sufficient moisture and nutrients for vegetable production.
A farmer notices soil crusting after rain events, making seedling emergence difficult. The most likely soil problem is:
Answer: Low aggregate stability and compaction-prone surface
Soil crusting is caused by poor aggregate stability — raindrops break apart surface aggregates, and they seal when dry, creating a hard crust that impedes emergence.
Which of the following best describes the role of mycorrhizal fungi in soil science relevant to GAP?
Answer: They extend plant root systems to improve nutrient and water uptake
Mycorrhizal fungi form symbiotic associations with plant roots, extending effective root surface area to enhance uptake of phosphorus, water, and other nutrients.