Soil Science & Fertilizer Chemistry Flashcards
7 cards from real CFA 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 & Fertilizer Chemistry flashcards as text
A soil test reports Mehlich-3 extractable boron at 0.4 ppm. For alfalfa production in most US recommendations, this level is considered:
Answer: Marginal to deficient
Most US recommendations rate Mehlich-3 boron below 0.5–0.6 ppm as marginal or deficient for high-demand crops like alfalfa, which requires boron for cell wall formation and pollen viability.
The Cation Exchange Capacity (CEC) of a soil would INCREASE if the soil's:
Answer: Organic matter content increased
Organic matter contributes large amounts of pH-dependent negative charge; adding organic matter increases the soil's ability to hold cations.
Which micronutrient deficiency is most commonly corrected by foliar application because soil-applied treatments are rapidly immobilized?
Answer: Iron
Soil-applied iron is rapidly converted to unavailable Fe3+ oxides in high-pH soils, making foliar iron sprays or chelated EDDHA forms the most effective correction methods.
The term 'luxury consumption' in plant nutrition refers to:
Answer: Uptake of nutrients at rates exceeding what is needed for maximum growth
Luxury consumption occurs when plants take up nutrients — especially potassium — in excess of growth requirements, storing them in vacuoles without a yield response.
When a soil has a pH of 5.5 and magnesium deficiency is suspected, which liming material addresses BOTH problems simultaneously?
Answer: Dolomitic limestone (CaMg(CO3)2)
Dolomitic limestone contains both calcium and magnesium carbonates, raising soil pH while simultaneously supplying magnesium to correct the deficiency.
Fertigation through a drip irrigation system is most advantageous compared to broadcast fertilization because it:
Answer: Places nutrients directly in the active root zone with high efficiency
Fertigation delivers soluble nutrients to the root zone where they are immediately available, improving nutrient use efficiency and allowing split applications matched to crop demand.
Which soil structure type, characterized by blocky aggregates with flat faces and sharp edges, is most commonly found in subsurface (B) horizons?
Answer: Angular blocky
Angular blocky structure, with its flat faces and sharp angles, is characteristic of subsoil B horizons where shrink-swell forces shape compacted aggregates.