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

A pH of 6.0–7.0 supports nutrient availability and beneficial microbial activity for most crops.

Question 2

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

Accepted Answer

Nitrogen

Answer

Nitrogen is a key component of chlorophyll and amino acids, driving vegetative growth and green coloration.

Question 3

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

Accepted Answer

Hold and supply nutrients

Answer

CEC measures the soil's capacity to hold positively charged nutrient ions and supply them to plants.

Question 4

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

Accepted Answer

Clay

Answer

Clay soils have small particles with large surface areas, giving them the greatest water-holding capacity.

Question 5

What is the primary function of phosphorus in plant nutrition?

Accepted Answer

Energy transfer and root development

Answer

Phosphorus is critical for ATP synthesis, energy transfer, and promoting root and seed development.

Agronomy Practice Test