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, LTU2 DPI Victoria, Geelong

Introducing “Subsoil Manuring”

….a new technology in SE Australiato increase productivity of problemsoils with dense clay subsoils….

Very dense

High clay

No pore space

The problem: dense clay subsoils

Reduced yieldsin dry springs

FEW ROOTS

Water logging in wet winters

“Small bucket size”

Is it possible ?

Research Project 2005-2007

Subsoil amelioration !

• control• deep ripped (DR)

• DR + gypsum• DR + MAP• DR + gyp/ MAP• DR + coarse sand

• DR + dynamic lifter (20 t/ha)• DR + lucerne pellets (20 t/ha)• DR + luc.pellets (20 t/ha) /MAP/gypsum

Research Project 2005-2007

Treatments

at 2 sites: - 4 years of grazing lucerne - continuous cropping

Subsoil manuring

2005 wheat crop

2006 wheat crop

Crop responses 2005, 2006

Year Control SS Man. (20 t/ha)

Crop

2005

2006

Wheat

Wheat

Grain yield (t/ha)

12.9

5.6

7.6

3.6

Control SS Man. (20 t/ha)

Grain protein (%)

9.1 13.4

10.8 13.9

02040600

20

40

60

80

02040600

20

40

60

80

Loss of soil water (mm) from subsoillayers during the 2005 crop

Depth(cm)

Soil water (mm) Soil water (mm)

CONTROL Subsoilmanuring

(- 57 mm) (- 123 mm)

*** **

*

0 20 40 60

Accumulation of soil water (mm) in subsoillayers during 2006 summer fallow

Depth(cm)

Soil water (mm)0 20 40 60

0

20

40

60

80

Soil water (mm)

CONTROL Subsoilmanuring

0

20

40

60

80

(+45 mm) (+125 mm)

*****

02040600

20

40

60

80

02040600

20

40

60

80

Loss of soil water (mm) from subsoillayers during the 2006 crop

Depth(cm)

Soil water (mm) Soil water (mm)

CONTROL Subsoilmanuring

(- 57 mm) (- 136 mm)

***

**

*

CONTROL 12.9 kg/mm

Subsoil Manuring 20.1 kg/mm

Rainfall-use efficiency in 2006 (kg grain/mm annual RF)

What is happening in the subsoil?

Subsoil 4 years after incorporation

Control: 30-40 cm Lucerne +: 30-40 cm

Across the bed

Subsoil manuring: why does it transform clay?manure

microbes

polysaccharides

+

clay particles

clay aggregates

Roots

Subsoil manuring: how much does it cost?

Poultry litter(equal to lucerne pellets)

Manure cost: $ 18-25 / tonne

Rate: 20 tonne / ha

Freight: say $ 8-15 / tonne

Incorporation: say $150 / ha

TOTAL = $ 670-950 /ha

Great interest among farmers

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.

Thank You