Nutrient Management and 4Rs 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 Nutrient Management and 4Rs flashcards as text
Which of the 4R principles addresses applying fertilizer in a way that minimizes leaching losses below the root zone?
Answer: Right Place
Right Place focuses on positioning nutrients within the root zone to maximize uptake and minimize leaching or runoff losses.
A soil test shows a pH of 5.2. Which nutrient is most likely to become toxic to plants under this acidic condition?
Answer: Manganese
Manganese solubility increases dramatically at low pH, and concentrations can reach phytotoxic levels in acidic soils.
A corn farmer applies nitrogen in the fall but experiences a wet spring. Which loss pathway is the greatest concern for the applied nitrogen?
Answer: Denitrification
Wet, warm, anaerobic soil conditions after fall nitrogen application promote denitrification, converting nitrate-N to gaseous N2 or N2O.
The Cation Exchange Capacity (CEC) of a soil directly affects which fertilizer management decision?
Answer: Determining split-application timing for nitrogen
Soils with low CEC hold fewer cations and are prone to nutrient leaching, making split applications more appropriate to avoid losses.
Which fertilizer formulation would be most appropriate for correcting a mid-season sulfur deficiency in wheat?
Answer: Foliar application of potassium sulfate
Foliar potassium sulfate provides rapid sulfur correction mid-season when soil application would be too slow to correct the deficiency.
Under the 4R framework, applying potassium in the fall for next year's corn crop is most consistent with which principle being compromised?
Answer: Right Time
Right Time means synchronizing nutrient availability with crop demand; fall K application for spring crops may be acceptable but applying N in fall misaligns timing.
A field with a long history of poultry litter applications tests very high for phosphorus. The 4R recommendation would be to:
Answer: Switch to a nitrogen-only fertilizer and eliminate phosphorus inputs
When soil P is very high, Right Rate means reducing or eliminating phosphorus inputs until soil P declines to agronomic optimum levels.