CFA Nutrient Management and 4Rs 3

Question 1

Which nitrogen transformation converts organic nitrogen into plant-available ammonium (NH4+)?

Accepted Answer

Mineralization

Answer

Mineralization is the microbial process that converts organic nitrogen compounds into inorganic ammonium available for plant uptake.

Question 2

A farmer wants to apply anhydrous ammonia (AA). Which soil condition makes this timing most risky for nitrogen retention?

Accepted Answer

Sandy soil with low organic matter

Answer

Sandy soils with low organic matter have minimal CEC, meaning injected ammonium can rapidly nitrify and leach as nitrate before crop uptake.

Question 3

The '4R' nutrient stewardship framework was developed primarily to achieve which goal?

Accepted Answer

Optimize agronomic, economic, social, and environmental outcomes simultaneously

Answer

The 4Rs aim to optimize all four outcomes—agronomic efficiency, economic returns, environmental protection, and social responsibility.

Question 4

Potassium deficiency symptoms in corn typically appear on which part of the plant first?

Accepted Answer

Oldest lower leaves showing scorching on leaf margins

Answer

Potassium is mobile in plants, so deficiency symptoms first appear on older lower leaves as the plant remobilizes K to new growth, causing marginal leaf scorch.

Question 5

A nutrient management plan recommends 180 lbs N/acre for corn. The farmer has 8,000 gallons/acre of liquid dairy manure testing 25 lbs N/1000 gallons total N with 50% plant availability. How much additional synthetic N is needed?

Accepted Answer

100 lbs N/acre

Answer

Manure provides 8 × 25 × 0.50 = 100 lbs available N/acre, so 180 - 100 = 80 lbs additional synthetic N is needed; answer B (100) is incorrect—the right answer is 80 lbs.

CFA Practice Test

CFA Practice Test

CFA Nutrient Management and 4Rs 3