The Soil Water Debate

I Know I Do Not Know

Soil Pedology

Effect of increasing rainfall on a soil sequence in NSW (From Koppi 1990).

Rainfall Characteristics North Ryde Jun 07 – Feb 08

26/0

6/20

07

10/0

7/20

07

24/0

7/20

07

7/08

/200

7

21/0

8/20

07

4/09

/200

7

18/0

9/20

07

2/10

/200

7

16/1

0/20

07

30/1

0/20

07

13/1

1/20

07

27/1

1/20

07

11/1

2/20

07

25/1

2/20

07

8/01

/200

8

22/0

1/20

08

5/02

/200

8

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

pH

pH

pH uS/m Rainfall (mm)

Average 5.5 78.1 12.7

Average Dev 0.6 85.8 8.8

Median 5.5 20.0 8.0

Min 3.0 0.0 2.0

Max 7.9 1371.0 51.0

Count 85.0 85.0 67.0

Matrix Potential vs Moisture Content for Two Soils ( From Hanks 1992 Pg 45

Table 2.5 )

-1000

-900

-800

-700

-600

-500

-400

-300

-200

-100

0

0.03

0.05

0.08

0.12

0.16 0.

2

0.24

Volumetric Moisture

Mat

rix

Po

ten

tial

SharpyLoam (m)

Geary SiltLoam (m)

Soil Physics

Soil Water Hysteresis

Conceptual and Parametric Representation of Soil Hydraulic Properties: A Review. Shmuel Assouline * and Dani Or. VZJ Vol. 12 No. 4

g Gravimetric MoistureMass H O Loss g

Mass Oven Dry Soil g( . )

. ( )

. . . .. 2

Soil Moisture Calculation

g g. 1

Moisture Content

  Camden Camden Boree Boree

Desc Measure Soil 1 Soil 1 Soil 2 Soil 2

Moisture Content

( Thea G ) 0.18 0.18 0.09 0.07

Bulk Density g cm 1.39 1.3 1.34 1.19

g g. 1

SOIL CHEMISTRY

Electrical Conductivity

Method Of Measurement – or What are we Measuring

ECe EC 1:5 ECw EC app EC1:1 EC 1:2

Soil Chemistry

Osmotic potential-0.36* (mmho/cm) (Osmotic potential) bar

Range 3-30mmhos

Total Cations or Anions from ECTotal Cations or Anions (mEq/l) 10*EC(mmho/cm)

Total Dissolved Salts (mg\l)from ECTDS(mg/l) 0.64 *EC(mmho/cm)

Formula for EC to Osmotic pressure, Total Cations and TDS. From Bresler, et al 1982

Other Debate POINTS

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