CFA Nutrient Sources and Management 3

Question 1

Denitrification in waterlogged soils converts nitrate primarily into:

Accepted Answer

Nitrogen gases (N₂ and N₂O)

Answer

Under anaerobic conditions, bacteria convert nitrate through denitrification to nitrogen gases (N₂ and N₂O) that escape into the atmosphere.

Question 2

Which micronutrient is most commonly deficient in high-pH, calcareous soils because it precipitates as insoluble compounds?

Accepted Answer

Iron

Answer

Iron availability drops sharply in high-pH soils because iron forms insoluble hydroxide and carbonate compounds, causing iron chlorosis.

Question 3

The nutrient management concept of the '4Rs' refers to right:

Accepted Answer

Source, Rate, Time, Place

Answer

The 4R Nutrient Stewardship framework stands for the right Source, right Rate, right Time, and right Place of fertilizer application.

Question 4

Which nitrogen source has the highest potential for ammonia volatilization when surface-applied to high-pH soils without incorporation?

Accepted Answer

Urea

Answer

Urea hydrolyzes rapidly to ammonium carbonate, which readily releases ammonia gas—especially problematic on high-pH soils.

Question 5

Luxury consumption of potassium occurs when:

Accepted Answer

Plants absorb K beyond their growth needs when soil K is high

Answer

Luxury consumption means plants absorb more potassium than required for maximum yield when soil potassium levels are high.

CFA Practice Test