Presentation made by Peter Clinnick to the Riverina branch of the Australian Society of Soil Science at a workshop held at 'Old Coree', Jerliderie, NSW on 22 February 2013. Presentation outlined how recommendations for effluent disposal on a sodic heavy clay were determined.

1. DeniliquinDeniliquin
Effluent Disposal ProjectEffluent Disposal Project
Land Resource, IrrigationLand Resource, Irrigation
and Enterprise Optionsand Enterprise Options
Peter ClinnickPeter Clinnick
Advanced Environmental Systems Pty LtdAdvanced Environmental Systems Pty Ltd
Creating a Sustainable FutureCreating a Sustainable Future
Tel (03) 5482 5882 Email:Tel (03) 5482 5882 Email: AES@Echuca.net.auAES@Echuca.net.au

3. The key management considerations were:
• Flooding
• Soil sodicity
• Nutrient loading
• Soil and wastewater salinity impacts
• Leaching and drainage management
• Hydraulic loading and watertable impacts
• Winter storage volumes and seasonal water use

4. •A landlocked depression dominates the centre of the site

5. Methods

7. SOILS
Red brown earth and (Sodosol) Deniboota sandy loam/loam
-Highest elevations and midslopes.
Transitional Red brown earth (Sodosol) Marah clay loam
- Mid and lower slopes.
Non self mulching clay (Vertosol) Riverina clay
-Drainage depressions.

9. Site No 62 64 65 66 69 78 80.0 84.0 85
ECe (dS/m)
(0-10 cm) 5.46 0.90 0.74 1.67 1.98 1.41 1.04 0.52 0.58
ECe (dS/m)
(10-40 cm) 5.67 6.01 3.08 10.26 6.05 13.50 0.31 1.06 7.65
Salinity
0.668 dS/m
wastewater

10. Sodicity in the root zone
Site No 62 64 65 66 69 78 80.0 84.0 85
ESP %
0-10cm 17.40 8.30 0.70 18.70 0.71 16.40 6.50 11.20 8.40
ESP %
~10-40cm 25.80 21.60 3.08 36.30 3.04 22.80 5.90 7.95 33.10

11. Effects of sodicity and compaction

12. Controlled traffic
• Lasered furrow irrigation is the preferred option in this
instance
• Some land (laser) grading may be required before
furrows can be constructed
• It is important for plant productivity that the extent of land
grading be minimised
The system advantage :
• It is compatible with controlled traffic management
• Less capital intensive than dripper or sprinkler systems

13. Economic: High
establishment costs
and low returns c. f.
irrigated crops.
Unsecured sales.
Social: Non identified.
Environmental: Low
fire risk Insect attack.
Carbon emissions in
harvesting.
Economic: Substitute for
agricultural production.
Social: Flow-on employment
with value adding.
Environmental: Expensive
set-up cost (`$8,000 per ha)
Rapid growth rates.
Estab $6-10,000
GM $700-1,000
ha/yr
Farm forestry
(Irrigated)
Economic:
Waterlogging losses in
wet years.
Social: Non identified.
Environmental:
Carbon emissions in
harvesting.
Economic: Opportunities for
value adding, summer feed
possibilities. Good markets
close-by.
Social: Employment in value
adding activities Assists in
maintaining demographics.
Environmental: Almost full
use of applied water.
Estab 800-3,000
(Crop only
$ 250-300)
GM~ $2,450/ha
Lucerne
(Irrigated)
Other costs and
disadvantages
Benefits and advantagesEstablishment
cost and gross
margin (per ha)
Enterprise Option
Enterprise Options

14. Economic: None identified.
Social: Low labour
requirement.
Environmental: Fire
damage/loss. Insect
attack. Carbon
emissions in harvesting.
Economic: Excellent gross margins.
Social: Flow-on employment.
Maintains demographics.
Environmental: Periodic labour
inputs.
Estab $3,000
GM ~$3-30,000
Years 4-5
1-2 kg/ha =>$2-3,000
Years 10=> 10 kg/ha
$2-
3,000/kg=$30,000
/ha
Forestry / horticultural
seed orchard
(Irrigated)
Economic: Skills need to be
acquired or purchased.
Social: Non identified.
Environmental: Risk of fire
or insect attack.
Economic: Good GM’s if well
managed and marketed.
Social: Flow-on employment
Maintains demographics.
Environmental: Improves water
balance.
Estab $6-10,000
GM $10-20,000
Cut foliage
(predominantly
eucalypts
Irrigated)
Other costs and
disadvantages
Benefits and advantagesEstablishment cost
and gross margin
(per ha)
Enterprise Option

15. Other crops considered
• Plums - Soil too sodic waterlogging in
winter, irrigation problems unless soil is
well managed
• Olives – Could grow, but not likely to be
an economic yield
• Grapes - ditto

17. Rec 11. Root zone sodicity requires close monitoring some leaching,
balance with watertable.
Rec 12. Irrigation control in line with associated drainage requirements
Rec 13. Deep ripping and mounding and substantial gypsum application 30T/ha
Rec 14. Nitrogen (N) (0-10 cm) depleted: Requirement for N of 20kg/ha.
Similarly, phosphorus requirements from 10-18 kg/ha.
Rec 15. Essential micronutrients depleted
Cu 0.5-1.5 kg/ha, Zn 3.75 kg/ha, Mo 0.025 kg/ha, Mn 0.5-1.5 kg/ha.
Rec 16. Subsurface drainage and serial biological disposal systems required
in the future if salinity / watertable levels increase
Rec 17. Green manure crops for several years to build up soil organic matter

19. Soil Mapping & Land Capability
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(03) 5482 5882
pc@environmentalsystems.com.au