CFA Soil Science and Testing 3

Question 1

A grower's soil test shows a base saturation of 65% calcium, 12% magnesium, and 4% potassium. What does this suggest?

Accepted Answer

Potassium is deficient and magnesium may be high

Answer

Optimal potassium base saturation is typically 2–5%, but 4% combined with 12% Mg suggests magnesium may be competing with potassium uptake, and potassium should be monitored.

Question 2

Which method is used to determine the soil texture class in the field without lab equipment?

Accepted Answer

Ribbon and feel method

Answer

The ribbon and feel method involves moistening a soil sample and working it between fingers to assess the length of ribbon formed, estimating sand, silt, and clay content.

Question 3

Soil bulk density is used to assess:

Accepted Answer

Degree of soil compaction

Answer

Bulk density measures the mass of dry soil per unit volume, with higher values indicating greater compaction and reduced pore space.

Question 4

When sulfur is applied to a high-pH soil, the expected outcome is:

Accepted Answer

Decreased soil pH over time

Answer

Elemental sulfur is oxidized by soil bacteria to form sulfuric acid, which acidifies the soil and lowers pH over time.

Question 5

The term 'soil profile' refers to:

Accepted Answer

A vertical cross-section of soil showing distinct horizontal layers

Answer

A soil profile is a vertical section from the surface to the parent material, showing distinct horizons (O, A, B, C) with different properties.

CFA Practice Test

CFA Practice Test

CFA Soil Science and Testing 3