Agronomy Soil Science and Fertility

Question 1

What soil pH range is generally considered optimal for most agronomic crops in the US?

Accepted Answer

6.0–7.0

Answer

4.5–5.5

Answer

7.5–8.5

Answer

8.0–9.0

Question 2

Which macronutrient is primarily responsible for vegetative growth and green color in plants?

Accepted Answer

Nitrogen

Answer

Phosphorus

Answer

Potassium

Answer

Calcium

Question 3

The cation exchange capacity (CEC) of a soil indicates its ability to do what?

Accepted Answer

Hold and supply nutrients

Answer

Drain excess water

Answer

Fix atmospheric nitrogen

Answer

Resist compaction

Question 4

Which soil textural class has the highest water-holding capacity?

Accepted Answer

Clay

Answer

Sand

Answer

Loam

Answer

Gravel

Question 5

What is the primary function of phosphorus in plant nutrition?

Accepted Answer

Energy transfer and root development

Answer

Chlorophyll synthesis

Answer

Disease resistance

Answer

Water regulation

Question 6

Which process converts ammonium (NH4+) to nitrate (NO3-) in the soil?

Accepted Answer

Nitrification

Answer

Denitrification

Answer

Mineralization

Answer

Immobilization