A presentation from the WCCA 2011 event held in Brisbane, Australia.

1. Increasing rainfall-use efficiency
for dryland crops on duplex soils
Sale P 1, Gill J 1, Peries R 2, Tang C 1
1 Department of Agricultural Sciences, LTU
2 DPI Victoria, Geelong

2. Introducing “Subsoil Manuring”
….a new technology in SE Australia
to increase productivity of problem
soils with dense clay subsoils….

3. The problem:
dense clay subsoils
Very dense
Water logging
in wet winters
No pore space
Reduced yields
in dry springs
FEW ROOTS

4. “Small bucket size”

5. Is it possible ?

6. Research Project 2005-2007
Subsoil amelioration !

7. Research Project 2005-2007
Treatments
• control
• deep ripped (DR)
• DR + gypsum
• DR + MAP
• DR + gyp/ MAP
• DR + coarse sand at 2 sites: - 4 years of grazing lucerne
• DR + dynamic lifter (20 t/ha) - continuous cropping
• DR + lucerne pellets (20 t/ha)
Subsoil manuring
• DR + luc.pellets (20 t/ha) /MAP/gypsum

8. 2005 wheat crop
2006 wheat crop

9. Crop responses 2005, 2006
Year Crop Control SS Man. Control SS Man.
(20 t/ha) (20 t/ha)
Grain yield (t/ha) Grain protein (%)
2005 Wheat 7.6 12.9 9.1 13.4
2006 Wheat 3.6 5.6 10.8 13.9

10. Loss of soil water (mm) from subsoil
layers during the 2005 crop
Soil water (mm) Soil water (mm)
60 40 20 0 60 40 20 0
0 0
20 20
Depth
* 40 40
(cm)
** 60 60
*** 80 80
(- 57 mm) (- 123 mm)
CONTROL Subsoil
manuring

11. Accumulation of soil water (mm) in subsoil
layers during 2006 summer fallow
Soil water (mm) Soil water (mm)
0 20 40 60 0 20 40 60
0 0
Depth 20 20
(cm) 40 40
60 60 **
80 80 ***
(+45 mm) (+125 mm)
CONTROL Subsoil
manuring

12. Loss of soil water (mm) from subsoil
layers during the 2006 crop
Soil water (mm) Soil water (mm)
60 40 20 0 60 40 20 0
0 0
20 20
* Depth
40 40
(cm)
** 60 60
*** 80 80
(- 57 mm) (- 136 mm)
CONTROL Subsoil
manuring

13. Rainfall-use efficiency in 2006
(kg grain/mm annual RF)
CONTROL 12.9 kg/mm
Subsoil Manuring 20.1 kg/mm

14. What is happening in the subsoil?
Subsoil 4 years after incorporation
Control: 30-40 cm Lucerne +: 30-40 cm
Across the bed

15. Subsoil manuring: why does it transform clay?
manure
microbes
+
polysaccharides
clay particles
Roots
clay aggregates

16. Subsoil manuring: how much does it cost?
Manure cost: $ 18-25 / tonne
Rate: 20 tonne / ha
Freight: say $ 8-15 / tonne
Incorporation: say $150 / ha
Poultry litter
TOTAL = $ 670-950 /ha (equal to lucerne pellets)

17. Great interest
among farmers

18. Acknowledgements
I would like to acknowledge GRDC for funding
(Project ULA0008), and the Australian Research
Council for funding (Project LP0455551),
and my co-authors Jaikirat Gill, Renick Peries,
and Caixian Tang for their great team effort.

19. Thank You