OPTIMISED WATER MOBILITY THROUGH MODIFYING DISPERSION AND IMPROVING SOIL STRUCTURE BEHAVIOUR

Innovation in Water Movement and Soil Health

John Saad - Managing Director CHT Australia

1

OUR STARTING POINT

* https://www.dpi.nsw.gov.au/__data/assets/pdf_file/0008/127277/Slaking-and-dispersion.pdf

Dispersion (the separation of soil into single particles) is governed by soil texture, clay type, soil

organic matter, soil salinity and exchangeable cations.*

INFLUENCED BY THE ADDITION OF CALCIUM

Slaking is the breakdown of a lump of soil into smaller fragments on wetting. It is caused when clay

swells and the trapped air bursts out. *

INFLUENCED BY THE ADDITION OF ORGANIC MATTER

2

CHEMISTRY OF SOIL CONDITIONERS

What might be used now What will also be used in the future

3

Poly cationic

Inorganic micro

emulsionsInorganic

Calcium

Sources

organic

Solutions

KCl

4

HOW TO MANAGE SURFACE TENSION

SURFACE TENSION OF

IRRIGATION SOLUTION

SURFACE TENSION OF

SOIL

5

OR

WHAT DOES THIS MEAN FOR CLAY SOILS

IF

THIS CONCEPT IS TRUE

THEN

WHAT SHOULD WE

EXPECT TO SEE

Greater infiltration of water

Greater Initial water uptake by soils

Greater water retention at depth

Better distribution of water through profile

Increased movement of soluble salts

Increased uptake of soluble salts by plants

Reduction EC at shallows

Increase EC at Depth

Enhanced soil friability

Reduced water discolouration

6

X RAY IMAGES OF DRY SODIC SOIL

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Fine & Loose

Friable?

Coarse & compacted Treatment Control

CHANGES IN SLAKING ?

Change in Water retentions?

SLAKING & DISPERSION CONTROLLED

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After 3 minutes immersion

9

Soil ball

made with

water

Dry core of the

soil ball but only

a thin layer is

wetted.

10

Soil ball made with

Aqua-Sil

Dry core of the soil ball

however homogenous

wetted from outside to

inside

FROM QUALITATIVE TO QUANTITATIVE PERSPECTIVES

Compare changes to slaking rate and water uptake

Compare changes to penetration resistance

Compare Changes in Water uptake and change in soil EC

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ARTICULATING THE BENEFIT –INCREASED PLANT AVAILABLE WATER

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0 3 6 9 12 15 18 21

w

e

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g

r

a

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s

Time in Minutes

Relative Slaking Profile Trend Lancewood #1

Control

Treatment

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Sustained

Retention of

water and

soil

STRUCTURE

BEHAVIOUR

CHANGE

CREATES

OPTIONS

FOR

IMPROVED

SOIL

FERTILITY

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5

10

15

20

0.00 1.50 3.00 4.50 6.00

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Time in Minutes

Tamworth Pierce SW - ControlReplicate 1

Replicate 2

Replicate 3

Replicate 4

Replicate 5

0

5

10

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0.00 1.50 3.00 4.50 6.00

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Time in minutes

Tamworth Pierce SW - Treatment

Replicate 1 Replicate 2 Replicate 3

Replicate 4 Replicate 5

14

3 fold

increase

in water

uptake

Structural

behaviour

changed

significantly

0

2

4

6

8

10

12

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0 10 20 30 40 50

g

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Time in Minutes

Tamworth Otech SW - Control

Replicate 1Replicate 2Replicate 3Replicate 4Replicate 5

0

5

10

15

20

0 10 20 30 40 50

g

r

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Time in minutes

Tamworth Otech SW - Treatment

replicate 1 Replicate 2 Replicate 3Replicate 4 Replicate 5 Replicate 6

ORGANIC VS INORGANIC POLYMER AFTER 1 YEAR APPLICATION

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0

1

2

3

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5

6

25 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 450 475 500 525 550 575 600 625 650 675 700 725 750

Pre

ssu

re (

kPa)

Depth (mm)

Block 7 (Aqua-sil Soil Conditioner) Linear (Block 7 (Aqua-sil Soil Conditioner))

0

1

2

3

4

5

6

25 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 450 475 500 525 550 575 600 625 650 675 700 725 750

Pre

ssu

re (

kPa)

Depth (mm)

Block 6 (SLS) Linear (Block 6 (SLS)) Linear (Block 6 (SLS))

EFFECT ON PENETRATION RESISTANCE - AGDI

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DISTRIBUTION OF VWC AT DEPTH AT WERRIBEE

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0

10

20

30

40

50

30 60 80

VWC

crop 3 may 2017

%

w

v

Aquasil N Aquasil S Control S Gypsum N Gypsum S Control N

DISTRIBUTION OF EC THROUGH DEPTH AT WERRIBEE

18

0

500

1000

1500

2000

30 60 80

EC

Crop 3 may 2017

E

C

m

s

Aquasil N Control S Control N Aquasil S Gypsum S Gypsum N

THE PATTERN IS CLEARPOORLY STRUCTURED HIGH SLAKING SOILS CAN BE REMEDIATED WITH AQUA-SIL

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Increased initial up take of water

Slow the tendency to Slake

Become more Water Stable Structure

Increase Water Retention Potential

Sustain Water Retention

Reduced Penetration resistance

Increased Friability

THE CONCEPTUAL EQUATION FOR SOIL AMELIORATION

CONVENTIONAL

Gypsum 2 – 5 tonnes per hectare

Organic Matter 10-20 tonnes per hectare

Deployment Dry weather

Mechanical spreading

3-5 weeks application Window

Alternative Chemistry

200 ppm of growth zone

Or 30- 60 kilo grams per Hectare

Deployment through high dilution

fertigation system

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CONCLUSION MORE PROOF?

21

Poly cationic Inorganic polymer emulsions with imparted surface

tension reduction properties are the new tool for soil health

management.

Calcium from Gypsum or Lime is no longer the only tool against

Dispersion

Organic Matter is no longer the only remedy to Slaking and water

retention for clay soils

Surface Tension and Charge balance are the levers to mitigate clay

swelling by controlling wetting rate of the substrate.

Aqua-Sil Provides the ability to manage soil surface tension and

soil charge balance through the fertigation and planting liquors.