This document discusses soil formation factors, properties, classification, and types of soils. It covers the natural factors of climate, organic material, relief, parent material, and time that influence soil formation. It also discusses human impacts. Key soil properties examined include color, texture, structure, consistence, porosity, and moisture. Several models for classifying soils are presented, including the soil taxonomy system and Keppen system. Specific soil orders like oxisols, ultisols, and mollisols are described along with pedogenic processes like laterization, podzolization, and calcification. Degradation processes are also addressed.

1. “The Soil is God’s Gift to the Living”
- Thomas Jefferson

2. Soil Formation Factors and
Management
Natural Factors
ClORPT
Climate
Organic Material
Relief
Parent Material
Time
The Human Factor

3. Soil Sampling and Mapping Units
Figure 15.1

4. A nearly
O
mature
profile…. A
10,000
years in E
the
making
B
Figure 15.2

5. Soil Properties
Color
An indication of material in the soil
Texture
An indication of the amount of weathering
Structure
An indication of its chemical and physical properties of
the parent material
Consistence
An indication of its structural integrity
Porosity
Related to texture – an indication of grain size
Moisture
An indication of the environment it is in

6. Soil Texture Triangle
Figure 15.3

7. Types of Soil Structure
Figure 15.4

8. Soil Colloids and Cation Exchange
Capacity
Figure 15.5

9. Soil Moisture and
Cation Exchange Capacity

10. pH Scale and Soils
Figure 15.6

11. Soil Classification
Soil Taxonomy
Classification of
soils based on
observed
properties
Diagnostic Soil
Horizons
Usually the O, A,
E, B horizons

12. The 12 Major Soil Orders of the
Soil Taxonomy
Zonal Soils Azonal Soils
Oxisols Entisols
Ultisols Inceptisols
Alfisols Andisols
Mollisols Vertisols
Aridisols Histosols
Gelisols
(Page 500 in your text)

13. Soil Taxonomy
Figure 15.8

14. The Factors Forming the Koeppen System
Figure 6.5

15. Pedogenic Regimes
Laterization
Movement of water freely through soils
Salinization
Laterization
Arid environments, water evaporates
leaving salts to build up in soils Gleization
Calcification
Moisture
Movement of calcium through the soil
through capillary water Podzolization
Podzolization
Slower movement of water through soils
allowing for build-up of strongly zonal Calcification
soils with water-logged lower horizons
Gleization Salinization
In cold environments, slow
decomposition of organic material Temperature
allowing it to build up over time.

16. Laterization
Heavy Rainfall
A – very little minerals left
Hot temperatures allow decomposers and
plant roots to remove organic material
quickly
B – only clay (sesquioxides) remain
Orange to red color comes from rusting of iron
Nearly all minerals are leached out – even sands and silts are washed
away leaving only thick clay layer

17. Oxisols
“Terra Rosa”
Figures 15.9, 15.11

18. Ultisols
Figure 15.19

19. Podzolization
Process
Figure 15.20

20. Alfisols
Figure 15.18

21. Spodosols
Figure 15.20

22. Calcification in
soil
Figure 15.17

23. Mollisols
Figures 15.14, 15.15

24. Mollisols
Figure 15.16

25. Aridisols
Figures 15.12, 15.13

26. Vertisols – an azonal soil
Figures 15.24, 15.25

27. Histosols – another
azonal soil
Figure 15.26

28. Gelisols
Figure 15.22

29. Soil Degradation
Figure 15.7