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Learning on the Run: Adaptive Salinity Management in the South Australian Lower Murray Region. Michael Cutting 1 , Tony Hoare 2 , Tapas Biswas 3 1 South Australian Murray-Darling Basin Natural Resources Management Board 2 Hoare Viticulture 3 Murray-Darling Basin Authority.
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Learning on the Run: Adaptive Salinity Management in the South Australian Lower Murray Region Michael Cutting1, Tony Hoare2, Tapas Biswas3 1 South Australian Murray-Darling Basin Natural Resources Management Board 2 Hoare Viticulture 3 Murray-Darling Basin Authority Irrigation Australia Limited Conference - Adelaide, 2012
Presentation Overview • Rootzone salinity management study commenced in 2006/07 as a collaboration between the South Australian Research & Development Institute (SARDI) and the SA Murray-Darling Basin Natural Resources Management Board • Water quality was an on-going issue for low yield wine grapes • Since study started significant changes have occurred over the years: water source, water availability, water quality, water taking rules • The presentation will highlight the value that on-going measuring and monitoring can assist on-farm decision making Study Area Finniss River Murray Mouth
Project Area (Regional) & Objectives • How much salt stays within the root-zone from summer irrigation and what is its distribution? • How does winter rainfall move salts within the profile? Study Area Finniss River River Murray Hindmarsh Island
Project Area (Vineyard) & Statistics Finniss River Variety: Cabernet Sauvignon Planting Year: 2002 Water Source: Finniss River/River Murray Irrigation System: Conventional Drip Flow Rate: 1.6L/hr Emitter Spacing: 0.5m Row Spacing: 3m Plant Spacing: 1.5m Application Rate: 1.1mm/hr Soil Type: Sandy Clay Loam over friable clay with occasional carbonate deposits Project Vineyard
0.3m 0.6m 0.9m Rootzone Salinity Monitoring Rootzone Salinity Monitoringwith SoluSAMPLER™™ Extraction tube PVC conduit Ceramic cup Sentek TriSCAN™ (www.sentek.com.au)
The Finniss River Flow The Finniss River: Flow vs. Salinity 30/05/2007 01/06/2007 System responds quickly to rainfall in the Eastern Mt Lofty Ranges – implications for salinity management!
>Drip: water salinity = 5.5 dS/m Big summer rain event Big winter rain event Winter Leaching Irrigation Window Summer Leaching Irrigation Grape threshold salinity Rootzone Salinity - 2006/07
2007/08 - 2010/11: Dry Growing…not by choice!! Impact of 2008 Heat Wave Finniss River March 2008
Rootzone Salinity 2007/08 – 2010/11 (No Irrigation) High levels of residual salts still observed in 2007/08
Rootzone Salinity - 2011/12 Irrigation water now sourced from River Murray pipeline ~200EC (0.2 dS/m) 259.2mm of rain since 1 May 2012
Rootzone Salinity Trend: 2006/07 – 2011/12 V. Poor WQ – + 6dS/m Irrigation resumed ~ 0.2 dS/m No irrigation: 4 x seasons Average rootzone salinity = 10.9dS/m Average rootzone salinity = 1dS/m
Lessons & Conclusions • Monitoring and managing root zone salinity is CRITICAL! • Summer leaching irrigation largely ineffective in displacing salts beyond the rootzone • Very low leaching efficiency if water quality is poor • Winter rainfall holds the key for salt displacement • Leaching irrigation in winter can leach more salts with less water • Appears that salinity tolerance is enhanced and greater ability to exclude salt under reduced yield production regime
Acknowledgements • SA MDB NRM Board • Mr. Tony Brooks (Vineyard Owner) - Strangers Reach Vineyard, Finniss SA • SENTEK Sensor Technologies Ltd • Mr. Tim Pitt (SARDI) • Peter Zurcher (ex UniSA)