280 likes | 470 Views
Redirecting rain to manage soil salinity: Lessons from groundwater and recycled wastewater irrigated vineyards. Tim Pitt , Rob Stevens, Jim Cox and Mike McCarthy SARDI – Water Resources, Viticulture & Irrigated Crops 4 June 2014. Outline. Salinity and yield response. Project Background.
E N D
Redirecting rain to manage soil salinity: Lessons from groundwater and recycled wastewater irrigated vineyards Tim Pitt, Rob Stevens, Jim Cox and Mike McCarthy SARDI – Water Resources, Viticulture & Irrigated Crops 4 June 2014
Outline • Salinity and yield response • Project Background Adelaide • Proof of concept – Padthaway (Groundwater) McLaren Vale • Pre-trial investigations • Hypothesis Padthaway • Results • Pilot study – McLaren Vale (Recycled Wastewater) Mt Gambier • Progress • Summary
Salinity and Yield Response = 1mS/cm 1000EC = 1000µS/cm = 1dS/m = 640mg/L = 640ppm
Project Background 2007 – 2009 salinity project developed for South East SA Emerging salinity damage Downward trend in rainfall Increasing groundwater salinity Introduction of regulated allocations 2010 – 2012 ‘Proof of concept’ trial • AIM – to identify techniques to manage rootzone salinity in vineyards receiving supplementary saline ‘groundwater’ irrigation
Proof of Concept • Padthaway: Adelaide • Wine grape (Chardonnay) • Sandy loam to clay over limestone Padthaway • Groundwater irrigation ~1.9 ML/yr Mt Gambier • Groundwater Irrigation ~2.2 dS/m (1400 ppm)
Proof of Concept Pre-trial measures 2009 • Salt symptoms in vines, petiole Cl-= 1-1.5 % (toxic) • Salt and sodicity distribution across vineyard floor • Salinity • Sodicity • Salinity higher UV than in MR • ECe (dS/m) • Sodicity higher UV than in MR • SAR • Infiltration >30 mm/hr at both points Under-vine Mid-row
Proof of Concept • ECe (dS/m) • Yield • decline • threshold • Average rootzone • salinity under-vine • Rain • Irrigation • (mm) • Autumn • Spring • Autumn • Spring • Winter rain flushing salt from rootzone • High SAR under-vine not impeding infiltration
Proof of Concept Hypothesis • Re-distributing rain falling on the mid-row to under the vine will reduce rootzone salinity
Soil EC • Plant Na+ and Cl- • Yield components • Vigour Proof of Concept
Proof of Concept Results 4.1dS/m 2.5dS/m Reduced under-vine soil salinity by 40%
Proof of Concept Results Re-directing rain from mid-row to under-vine soils: • reduced juice Na+ by 25 % and Cl- by 40 %
Proof of concept Pilot study PROBLEM Will more commercial treatments be as effective? • Treatments are NOT commercially viable!! A B C D E
Pilot Study • McLaren Vale: Adelaide • Wine grape (Cabernet Sauvignon) McLaren Vale • Clay loam over medium clay Padthaway • Recycled Wastewater irrigation ~1.4 ML/yr Mt Gambier • Recycled Wastewater irrigation ~1.2 dS/m (770 ppm)
Pilot Study Pre-trial - Vintage 2013 • Soil salinity (Sept 2012) • ECe (dS/m) Petiole (Nov 2012) • Cl- < 0.5 % • Na+ < 0.15 % Under-vine Mid-row
Pilot Study A B Control (no change) Mid-row plastic covered mound
Pilot Study C Mid-row mound
Pilot Study D Mid-row mound sprayed with surface sealing polymer
Pilot Study E Buried plastic covered mid-row mound
Pilot Study Vintage 2013 Treatments installed in December 2012 A B C D E < 20 mm rain between treatment construction and vintage 2013 Yield = 2.2 kg/vine Sugar = 25.3°Brix pH = 3.5 TA = 6.0 g/L Na = 20 mg/L Cl = 30 mg/L UV soil = 3.3 dS/m MR soil = 0.9 dS/m Pruning wt = 1.7 kg/vine No significant difference in: • harvest data • post-harvest soils • pruning weights
Pilot Study Vintage 2014 No difference in: number of bunches 113/vine berry weight 0.83 g juice pH 3.6
Pilot Study Vintage 2014 Leaf petiole at flowering: Trends emerge at P=0.1
Pilot Study Vintage 2014 Leaf blade at harvest:
Pilot Study Vintage 2014 Grape juice at harvest: Trends emerge at P=0.1
Summary • Proof of concept – Groundwater, Padthaway SA • Rainfall redirection: • reduced under-vine soil salinity by 40% • reduced juice sodium by 25% • reduced juice chloride by 40% • ‘Proof of concept’ treatments commercially impractical • Pilot study – Recycled Wastewater, McLaren Vale SA • Early results consistent with ‘Proof of Concept’ trial • (Same response with different climate, soil, management etc.) • Commercially applicable treatments differentiate at P=0.1
Further information from: www.npsi.gov.au/products/npsi1212 Agricultural Water Management Vol 129, Nov 2013, p130-137
Further information from: australianwaterrecycling.com.au goyder.sa.gov.au Tim Pitt SARDI – Water Resources, Viticulture & Irrigated Crops T. 08 8303 9690 M. 0434 600 504 tim.pitt@sa.gov.au