Weathering Processes | Soil Genesis and Development, Scenario 1 - Agroecosystem Soil, Food and Fiber

Figure 1. The influence of the interaction of temperature and rainfall on processes of physical and chemical weathering. Notice that as annual rainfall and temperature increases, chemical weathering dominates over physical weathering. On the contrary, notice that as the temperature lowers, physical weathering begins to dominate over chemical weathering. *Image courtesy of UNL, 2005*

Quiz

Question

Question 4a: What weathering processes dominate in Alabama‏?

To review this concept click on the link: Soil Genesis and Development Lesson 2 (& see Fig.1 above)

Physical

Physical weathering is the weakening and subsequent disintegration of rock by physical forces. These physical forces include temperature fluctuation very high to very low, abrasion, shrink-swell, frost action or freezing and thawing, and salt crystal growth.

Chemical

High temperature and especially moisture are critical for chemical weathering. chemical weathering generally occurs more quickly in warm and moist climatic regions.

Biological

Biological weathering is the weakening and subsequent disintegration of rock an minerals by plants, animals and microbes.

Slight Physical & Moderate Chemical

Temperature and moisture are ample for very strong chemical weathering.

Moderate Physical & Slight Chemical

Temperature is not cold enough to have physical weathering.

Looks Good! High temperature and especially moisture are critical for chemical weathering. chemical weathering generally occurs more quickly in warm and moist climatic regions.

Question

Question 4b: What weathering processes dominate in Nebraska‏?

To review this concept click on the link: Soil Genesis and Development Lesson 2 (& see Fig.1 above)

Physical

Mollisols have developed on grasslands under vegetation that has extensive fibrous root systems. The topsoil of Mollisols is usually dark and rich with organic matter, giving it a lot of natural fertility.

Chemical

High temperature and especially moisture are critical for chemical weathering. Chemical weathering generally occurs more quickly in warm and moist climatic regions.

Biological

Entisols are soils with little profile (horizon) development. Although Entisols can be found in Alabama with unstable environments, the profile shown in the image is more developed.

Slight Physical & Moderate Chemical

Temperature is ample for chemical weathering but moisture is not as ample as Alabama Also, frost action (physical weathering) will play a role in weathering since winters are cold.

Moderate Physical & Slight Chemical

Temperature and moisture are ample enough for moderate chemical weathering, however, winters are not cold enough and long enough to result in moderate physical weathering.

Looks Good! Temperature is ample for chemical weathering but moisture is not as ample as Alabama Also, frost action (physical weathering) will play a role in weathering since winters are cold.

Reflection

What weathering processes dominate in Alabama?

Physical
Chemical
Biological
Slight physical & moderate chemical
Moderate physical & slight chemical

What weathering processes dominate in Nebraska?

Physical
Chemical
Biological
Slight physical & moderate chemical
Moderate physical & slight chemical