CFA Nutrient Sources and Management 2

Question 1

Which fertilizer material is considered an organic nitrogen source because it releases nitrogen through microbial decomposition?

Accepted Answer

Feather meal

Answer

Feather meal is an organic nitrogen source that releases nitrogen slowly as soil microbes break down the protein.

Question 2

A fertilizer label reads 10-20-10. What is the percentage of phosphate (P₂O₅) in this product?

Accepted Answer

20%

Answer

The second number in the N-P-K grade always represents the percentage of available phosphate (P₂O₅), which is 20%.

Question 3

Which form of phosphorus do plant roots actually absorb from the soil solution?

Accepted Answer

Orthophosphate (H₂PO₄⁻ or HPO₄²⁻)

Answer

Plant roots absorb phosphorus as orthophosphate ions (H₂PO₄⁻ or HPO₄²⁻) from the soil solution.

Question 4

Sulfur-coated urea releases nitrogen more slowly than regular urea primarily because:

Accepted Answer

The coating must degrade before water can dissolve the urea

Answer

The sulfur coating acts as a physical barrier; moisture must penetrate or degrade it before the urea core dissolves and becomes available.

Question 5

When manure is surface-applied without incorporation, the greatest nutrient loss risk is:

Accepted Answer

Ammonia volatilization from nitrogen

Answer

Ammonium-nitrogen in unincorporated manure readily volatilizes as ammonia gas, especially in warm, windy conditions.

CFA Practice Test