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 Study Area Australian Research & Development Institute (SARDI) and the SA Murray-Darling Basin Natural Resources Management Board Finniss River 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 Murray Mouth and monitoring can assist on-farm decision making Project Area (Regional) & Objectives Study Area Finniss River 1. How much salt stays within the root-zone from summer irrigation and what is its distribution? 2. How does winter rainfall move salts within the profile? River Murray Hindmarsh Island Project Area (Vineyard) & Statistics Finniss River Project Vineyard 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 Rootzone Salinity Monitoring Rootzone Salinity Monitoring with SoluSAMPLER™™ Extraction tube 0.3m 0.6m PVC conduit 0.9m Ceramic cup Sentek TriSCAN™ (www.sentek.com.au) The Finniss River: Flow vs. Salinity The Finniss River Flow 30/05/2007 01/06/2007 System responds quickly to rainfall in the Eastern Mt Lofty Ranges – implications for salinity management! Date 1/08/2007 18/07/2007 4/07/2007 20/06/2007 6/06/2007 23/05/2007 9/05/2007 25/04/2007 11/04/2007 28/03/2007 14/03/2007 28/02/2007 14/02/2007 31/01/2007 17/01/2007 3/01/2007 20/12/2006 6/12/2006 22/11/2006 8/11/2006 25/10/2006 Salinity (dS/m) Irrigation Water Salinity – 2006/07 (Finniss River) 7 6 5 4 3 2 1 0 Rootzone Salinity - 2006/07 50 14.0 Irrigation Rainfall Soln 30cm Soln 60cm Soln 90cm ETo 45 40 >Drip: water salinity = 5.5 dS/m 12.0 Big summer rain event Big winter rain event Irrigation/Rainfall (mm) 30 8.0 25 6.0 20 Winter Leaching Irrigation Window 15 Summer Leaching Irrigation Grape threshold salinity 10 4.0 2.0 5 0 1/07/06 0.0 1/09/06 1/11/06 1/01/07 1/03/07 1/05/07 1/07/07 1/09/07 EC (dS/m) or ETo (mm) 10.0 35 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) 60 50 14 12 Irrigation Rainfall ECsw 30cm ECsw 90cm 8 30 6 20 4 10 2 0 1/07/2007 0 1/01/2008 1/07/2008 1/01/2009 1/07/2009 1/01/2010 1/07/2010 1/01/2011 EC (dS/m) or ETo (mm) Irrigation/Rainfall (mm) 40 10 High levels of residual salts still observed in 2007/08 ECsw 60cm Rootzone Salinity - 2011/12 60 50 14 Irrigation Irrigation water now sourced from River Murray pipeline ~200EC (0.2 dS/m) 12 40 10 ECsw 30cm 259.2mm of rain since 1 May 2012 ECsw 60cm 30 ECsw 90cm 8 6 20 4 10 2 0 1/07/2011 0 1/01/2012 EC (dS/m) or ETo (mm) Irrigation/Rainfall (mm) Rainfall Rootzone Salinity Trend: 2006/07 – 2011/12 60 14 50 Average rootzone salinity = 10.9dS/m Irrigation/Rainfall (mm) 40 Irrigation resumed ~ 0.2 dS/m No irrigation: 4 x seasons 12 10 Irrigation Rainfall ECsw 30cm 8 ECsw 60cm 30 ECsw 90cm 6 20 4 10 0 1/07/2006 EC (dS/m) or ETo (mm) V. Poor WQ – + 6dS/m 2 Average 1/07/2007 1/07/2008 1/07/2009 1/07/2010 1/07/2011 rootzone salinity = 0 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)