1. Soil Physics with HYDRUS: Chapter 1
Equations, Tables, and Figures

2. 1.1 – 1.5

3. 1.6 – 1.10

4. 1.11 – 1.13

5. TABLE 1.1
Approximate charge characteristics of soil colloids (Brady and Weil, 2008)
Colloid Type
CEC
AEC
cmolc kg-1
Organic matter
200
Smectite
100
Vermiculite
150
Fine-grained micas 30
Chlorite
Kaolinite 8 2
Aluminum oxide 4 5
Iron oxide
Allophane 15

6. TABLE 1.2
Specific surface area range for selected colloids (Skopp, 2000)
Colloid s
m2 g-1
Kaolinite
15-20
Illite
80-100
Bentonite
Montmorillonite
Crystalline iron oxides
Amorphous iron oxides
Organic matter
TABLE 1.3
Specific surface area for bulk soils (Skopp, 2000)
Soil Textural Class s
m2 g-1
Sands
<10
loams and silt loams
5-20
Clay loams
15-40
Clays
>25

7. TABLE 1.4
Size classes of soil structure (Soil Survey Manual, 2008)
Size Class
Platy†
Prismatic or Columnar
Blocky
Granular Mm mm
Very fine
<1
<10
<5
Fine
1-2
10-20
5-10
Medium
2-5
20-50
Coarse
50-100
Very Coarse
>10
>100
>50

8. Depth Textural Class Structure Color cm
TABLE 1.5
Cecil soil series description (plot 4 from Bruce et al., 1983)
Horizon
Depth
Textural Class
Structure
Color cm Ap
0-21
Loamy sand
Weak, medium granular
Brown BA
21-26
Clay loam
Weak, medium, subangular blocky
Red
Bt1
26-102
Clay
Strong, medium, subangular blocky
Red with few strong brown mottles
Bt2 BC C
251+
Sandy clay loam
Massive
Red with light red and weak red mottles