CCA Nutrient Management 3

Question 1

A corn crop yielding 200 bu/acre removes approximately how many pounds of nitrogen in the grain?

Accepted Answer

160 lbs N/acre

Answer

Corn grain contains roughly 0.8 lb N per bushel, so 200 bu × 0.8 = 160 lbs N removed in grain at harvest.

Question 2

Denitrification is most likely to accelerate under which combination of conditions?

Accepted Answer

Warm, saturated soil with available carbon

Answer

Denitrifying bacteria thrive when soils are warm, anaerobic (saturated), and have readily available carbon as an energy source.

Question 3

Which phosphorus soil test method is most widely recommended for soils with neutral to alkaline pH in western U.S. states?

Accepted Answer

Olsen (NaHCO₃)

Answer

The Olsen bicarbonate method is preferred for neutral to calcareous soils because Bray P-1 acid extraction underestimates available P at high pH.

Question 4

The primary function of boron in plants is related to:

Accepted Answer

Cell wall formation and structural integrity

Answer

Boron is essential for cell wall cross-linking, pollen germination, and sugar transport, making it critical to structural development.

Question 5

When computing a nitrogen budget using the maximum return to nitrogen (MRTN) approach, the primary economic inputs are:

Accepted Answer

Corn price and nitrogen fertilizer cost

Answer

MRTN calculations identify the N rate that maximizes profit by comparing the cost of N fertilizer against the value of the resulting yield response.

(CCA) Certified Crop Advisor Practice Test