The synergy of raised beds, controlled traffic, minimum tillage and stubble retention deliver higher water use efficiency in South West

Victoria, Australia

Renick Peries, DPI, Victoria &Jaikirat Singh-Gill, LTU, Victoria

Acknowledgments

• Jaikirat S-Gill, Peter Sale, C Tang – LTU

• DPI colleagues: Bruce Wightman, Chris Bluett, Tim Johnston

• Southern Farming Systems

• Farmer Collaborators: John Sheehan, Brent Herrmann, Lachlan Wilson, George Burdett, Rowan Peel

• Department of Primary Industries, Victoria

• GRDC Australia

So, why raise beds in South-West Victoria?

• Water logging (perched water table), in the HRZ (550-750mm RF)• Improved drainage • temporal changes to soil physical properties with CT

Barley on raised beds

Barley on the flat (waterlogged)

raised bed journey: mid 90’s to 2011

• change in land use (grazing to cropping)- 1995/96• cropping resulted in water logging in the HRZ (550-750mm

rainfall)• raised beds improved drainage and • created opportunities for CA practices ?• stubble management – improvements in infiltration• removal of compaction (CT) – better root proliferation• deep rooted legumes – rotation management / soil str.• 60,000 ha of raised beds by 2006• Innovation also creates challenges

Our Challenges?

• Water- too much of it or lack of it ! (recent phenomenon)

• Soils

Problem soils of the western district (HRZ)GREY SODIC VERTOSOL

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sodic

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Problem soils of the western district (HRZ) BLACK SELF-MULCHING VERTOSOL

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Problem soils of the western district (HRZ) The Grey Sodosol

raised beds in HRZ - five years on …………

Temporal development of soil Structure?

Raised beds in HRZ - five years on ………

Temporal development

of soil Structure

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Dep

th o

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Difference (%) in macroporosity

Black V Grey SV

15.6

14.4

15.2

15.4

9.6

5.6

4.5

4.3

Macro-porosity in the long-term flat pasture state

Temporal change in Plant Available Water Capacity• at bed installation, both soils were similar in their PAWC to 40 cm depth (approx 65 mm)• from 40-100 cm depth the BV had twice the PAWC (54mm) compared to GSV (29mm)• at three and five years after bed installation (1999) the more hostile sodic soil had gained

greater PAWC compared to the black vertosol• the extra PAWC would provide a crop insurance even during ‘drought’ years • the black vertosol would appear to be more suited to CT without beds

Soil type response to soil water storage (mm) 2004

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0.1

0.3

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th o

f p

rofi

le (

cm)

lsd(P=0.001)=4.14

Storage(0-40)

GSV>BV

lsd(P=0.001)=9.4

Soil type response to soil water storage (mm) 2002

-20 -10 0 10 20 30

0.1

0.3

Dep

th o

f p

rofi

le (

cm)

lsd(P=0.001)=7.6

BV GSV

Storage (0-40) GSV>BV. lsd(P=0.001)=12.

Raised beds offer crop insurance during drought

• water use 20-30cm depth• Good agronomy – yield 1.5 t/ha

Our Challenges?

• Water• Soils• Stubble

stubble issues on raised beds• Improved soil/better drainage/ good agronomy – contribute to

heavy biomass• Subsoil constraints- low HI – heavy stubble loads• Over many years burning was the only option!• Efficient machinery / canopy management • Seasonal rainfall a critical factor!

stubble issues on raised beds• Beds can get water logged if not properly designed• Under ‘wet’ conditions – pests were (& are) a major issue• To burn or not to burn- a climate specific decision?• In ‘wet’ seasons even low stubble loads can be an issue

Overall benefits of the ongoing initiatives?

2 m beds: Derrinallum 3 m beds: Winchelsea

Benchmarking WUE in HRZ (Vic) 2009

Wheat yield SW Vic

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April-November rain (mm)

Yie

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Mr A

Mr B

Mr C

Mr D

Mr E

Mr F

Mr G

French and Schultz

Sadras and Angus

Our Challenges?

• Water √• Soils √• Stubble √• Addressing subsoil PAWC - for low WUE

How do we enhance the bucket size?

subsoil manuring- benefits & setbacks• Improves connectivity between

topsoil & subsoil

• Improves aeration & conductivity

• Improves bucket size

• Improves soil biology ?

• Improves yield & WUE

• Can be a component of a RB package, if

• Tillage vs CA !

• Currently Expensive

Transformation of the subsoil, four years after subsoil manuring (Ballan November 2009).

May 2005 : 20 t/ha Lucerne pellets + gypsum + some DAP, applied in two rip lines per 2m wide raised bed

Photo by Peter Sale, LTU

Subsoil (30-40 cm depth)In Control treatment

Subsoil (30-40 cm depth)In Deep Organic treatment

Subsoil manuring increases PAWC in hostile subsoil

(Improved fallow efficiency)

(a) Summer Fallow (b) Vegetative growth (c) Grain filling

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After J S Gill et.al., (In press)

How major issues are impacting on farmer behaviour

• Land use change: Flat to raised beds

• Drought : Raised beds to flat !

• Rainfall variation : Stubble retained to stubble burn!

• With full realisation of soil issues: Beds-Flat-Beds

• What next?

Why change from raised beds to flat CT?

• drought? was the message lost?• loss of area to furrows (20%) or• CT without beds - the way forward for some!

June 2005

Sept 2011

from 2m raised beds to 3m controlled traffic and back to 3m raised beds

2010 2011 (rainfall mm)

Jan-Mar 124.8 205.9

Apr-August 274.5 219.9

Sept-Nov 235.0

A success story: From flat – 2m raised beds (1995)From 2 m beds to 3m CT(2006)From 3 m CT to 3m raised beds (2011)!

Summary• South-West Victoria is continuing to adapt to change

made necessary by economic & climatic considerations

• While there is significant appreciation of CA in the region, not all of the CA practices appeal to all farmer champions

• The synergy of raised beds, CT & stubble retention have raised crop yields towards potential WUE in the region

• There may need to be more flexibility and clarity in the definition of CA applications in this region

Thank You