The synergy of raised beds, controlled traffic, minimum tillage and stubble retention deliver higher water use efficiency in South West Victoria, Australia. Renick Peries
The synergy of raised beds, controlled traffic, minimum tillage andstubble 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?• Waterlogging (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 Clay % 0 depth (cm) 50 100 150 0 20 40 60 80 100 Sodicity Clay (%) 0 strongly sodic depth (cm) 50 sodic 100 non 150 sodic 0 10 20 30 40 50 60 ESP (%)
Problem soils of the western district (HRZ) BLACK SELF-MULCHING VERTOSOL Clay % 0 20 depth (cm) 40 60 80 100 0 20 40 60 80 100 Clay (%) Sodicity 0 20 strongly sodic depth (cm) 40 sodic 60 80 non sodic 100 0 10 20 30 40 50 60 ESP (%)
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 ……… Difference (%) in macroporosityTemporal development -5 0 5 10 15 15.6of soil Structure 14.4 5 Depth of profile (cm) 15.2 15 15.4 Black V Grey SV 9.6 25 5.6 4.5 4.3 35 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 w ater storage (m m ) Soil type response to soil w ater storage (m m ) 2002 2004 -20 -10 0 10 20 30 -20 -10 0 10 20 30 Depth of profile (cm) 0.1 Depth of profile (cm) lsd(P=0.001)=7.6 0.1 lsd(P=0.001)=4.14 BV GSV S t or a ge ( 0 - 4 0 ) St o r ag e ( 0 - 4 0 ) 0.3 GS V>B V 0.3 GSV >B V . l sd( P =0 . 0 0 1) =9 . 4 lsd ( P=0 .0 0 1) =12 .
Raised beds offer crop insurance during drought• water use 20-30cm depth• Good agronomy – yield 1.5 t/ha
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 10 9 Mr A 8 Mr B 7 Mr CYield (t/ha) 6 Mr D 5 Mr E 4 Mr F 3 Mr G French and Schultz 2 Sadras and Angus 1 0 0 100 200 300 400 500 600 700 April-November rain (mm)
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). Subsoil (30-40 cm depth) Subsoil (30-40 cm depth) In Control treatment In Deep Organic treatmentMay 2005 : 20 t/ha Lucerne pellets + gypsum + some DAP, applied in two rip lines per 2m wide raised bedPhoto by Peter Sale, LTU
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 124.8 205.9Apr-August 274.5 219.9Sept-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 madenecessary by economic & climatic considerations• While there is significant appreciation of CA in theregion, not all of the CA practices appeal to all farmerchampions• The synergy of raised beds, CT & stubble retention haveraised crop yields towards potential WUE in the region• There may need to be more flexibility and clarity in thedefinition of CA applications in this region