Final Study Guide - Soil Aeration

Question 1

What are the main gases found in soils?

Answer 1

Nitrogen, oxygen, carbon dioxide

Question 2

How does the CO2 concentration in soils compare to the CO2 of the atmosphere?

Answer 2

Atmospheric composition: 0.0376%

Soil concentration: 0.3-20%
*(normal range 0.3-3%)

Question 3

What is the predominant process that drives gas exchange between soils and the atmosphere?

Answer 3

Mass flow (less important) and diffusion (more important)

Question 4

What is redox potential and why is so strongly associated with oxygen concentration?

Answer 4

Redox potential is the tendency for electrons to be transferred from one element to another

It is strongly associated w/ O concentration because O is the strongest oxidizing agent

Question 5

How does water saturation affect soil redox potential?

Answer 5

Redox potential decreases
shortly after soil water
saturation

Question 6

What are alternate electron acceptors and how does the use of alternate electron acceptors drive the efficiency of reactions such as decomposition?

Answer 6

Nitrogen, manganese, iron, sulfur, carbon. Use of alternate e- acceptors decreases reaction efficiency

Question 7

What two greenhouse gasses can be produced under anaerobic conditions in soils?

Answer 7

N2O and CH4

Question 8

Give some examples of management strategies to improve soil aeration

Answer 8

Tillage at the proper soil moisture content creates large pores for faster oxygen diffusion (short-term solution)

Addition of organic matter (long-term solution)

Soil drainage (ditches or pipes)