CFA Nutrient Management & Application Planning 2 — Questions and Answers
Question 1: A soil test indicates a phosphorus level of 45 ppm in a field intended for corn production. According to typical nutrient management guidelines, this level would be considered:
- Deficient, requiring heavy P application
- Sufficient, requiring maintenance rates only (Correct answer)
- Excessive, and no P application is recommended
- Toxic to corn at this concentration
Correct answer: Sufficient, requiring maintenance rates only
A phosphorus level of 45 ppm is generally in the sufficient range for corn, warranting only maintenance applications rather than build-up rates.
Question 2: When developing a nutrient management plan, the concept of 'realistic yield goal' is important because it:
- Ensures maximum fertilizer sales for the dealer
- Prevents over-application by setting achievable production targets (Correct answer)
- Is required only for organic farming operations
- Applies solely to nitrogen recommendations
Correct answer: Prevents over-application by setting achievable production targets
Realistic yield goals prevent over-application of nutrients by basing recommendations on achievable yields based on soil productivity and historical performance.
Question 3: Which of the following best describes 'luxury consumption' in plant nutrition?
- Plants absorbing more nutrients than needed for maximum growth (Correct answer)
- A premium fertilizer product line
- The practice of applying extra nutrients as insurance
- Nutrients stored in luxury form in the soil
Correct answer: Plants absorbing more nutrients than needed for maximum growth
Luxury consumption occurs when plants absorb nutrients in excess of what is needed for maximum growth, which does not translate to additional yield.
Question 4: A farmer reports that crop response to potassium fertilizer has been poor despite low soil K test levels. The MOST likely explanation is:
- The potassium was applied at the wrong time of day
- Soil pH is too low, limiting K availability (Correct answer)
- Potassium never improves crop yields
- The crop variety does not require potassium
Correct answer: Soil pH is too low, limiting K availability
Low soil pH can limit potassium availability and uptake even when soil test K levels appear deficient, making pH correction a priority.
Question 5: In split nitrogen applications, a portion of N is applied at planting and the rest during the growing season. The PRIMARY benefit of this approach is:
- It reduces the total amount of nitrogen needed
- It decreases application costs significantly
- It reduces leaching and volatilization losses (Correct answer)
- It improves soil pH over time
Correct answer: It reduces leaching and volatilization losses
Split nitrogen applications reduce losses from leaching and volatilization by providing N closer to when the crop needs it, improving nitrogen use efficiency.
Question 6: When calculating fertilizer application rates, a grower needs to apply 120 lbs of actual nitrogen per acre using a 46-0-0 fertilizer. How many lbs of product per acre are needed?
- 55 lbs/acre
- 261 lbs/acre (Correct answer)
- 174 lbs/acre
- 120 lbs/acre
Correct answer: 261 lbs/acre
Dividing the actual N needed (120 lbs) by the fertilizer N concentration (0.46) gives 261 lbs of 46-0-0 product per acre.
Question 7: Organic matter in soil contributes to nutrient management primarily by:
- Directly supplying all macro and micronutrients in plant-available form
- Providing a slow-release reservoir of N, P, and S through mineralization (Correct answer)
- Increasing soil bulk density and improving drainage
- Reducing the need for any fertilizer applications permanently
Correct answer: Providing a slow-release reservoir of N, P, and S through mineralization
Soil organic matter releases nitrogen, phosphorus, and sulfur slowly through microbial mineralization, serving as a natural nutrient reservoir.
CFA Nutrient Management & Application Planning 2
A soil test indicates a phosphorus level of 45 ppm in a field intended for corn production.
According to typical nutrient management guidelines, this level would be considered: