Technical Yearbook 2024

Contents

VITICULTURE Promotion of wild bees in South African and Austrian vineyards by plants with diverse floral traits ........................... 7 Mapping individual vines using drone imagery ....................10 Treated municipal wastewater for irrigation (Part 1): Irrigation application and water quality .................................13 Treated municipal wastewater for irrigation (Part 2): Grapevine water status and vegetative responses .................17 Treated municipal wastewater for irrigation (Part 3): Yield and juice characteristics ..................................................21 Treated municipal wastewater for irrigation (Part 4): Soil chemical responses ............................................................28 Treated municipal wastewater for irrigation (Part 5): Soil hydraulic conductivity .......................................................33 Biosand reactors as a feasible solution for the treatment of winery wastewater (Part 1) ......................................................36 Biosand reactors and anaerobic digestion – a zero-waste model for winery wastewater (Part 2) ....................................40 The quest for new Pinotage clones ..........................................43 In-field fractional use of winery wastewater with raw water (Part 1): Plot selection, augmentation and climatic conditions ....................................................................46 In-field fractional use of winery wastewater with raw water (Part 2): Irrigation application, water quality and nutrient load ...............................................51 In-field fractional use of winery wastewater with raw water (Part 3): Soil responses ..........................................56 In-field fractional use of winery wastewater with raw water (Part 4): Grapevine and wine responses ..............62 In-field fractional use of winery wastewater with raw water (Part 5): Assessment of the below and above-ground chemical status of grapevines in the lower Olifants River region ......................................................68 High(er)-throughput evaluation of novel grapevine material for important traits ....................................................73 Understanding and controlling Phomopsis (‘streepvlek’) in Western Cape vineyards ...............................75 The grapevine collection at ARC Infruitec-Nietvoorbij ........78 Biocontrol in viticulture ............................................................81 Impact of GHS on evaluation of IPW spray programmes ....................................................................84

OENOLOGY Hydrogen sulphide formation in canned wines – the role of liners and wine composition .................................86 Bioprotection as an alternative to SO 2 in the pre-fermentation phase ............................................................88 Yeast cell density and the effect on volatile thiol formation ......91 Calcium tartrate instability ......................................................93 Electronic noses .........................................................................96 Towards a circular economy in winemaking – re-utilisation of yeast lees .........................................................98 Plant-based proteins in oenology ..........................................100 The use of carrageenan in calcium tartrate and protein stabilisation of wines ...............................................................105 Stirring things up – Sauvignon blanc juice stabulation .....107 PRACTICAL IN THE VINEYARD Under-vine living mulches .....................................................110 Waterlogged conditions in vineyards ...................................112 Vineyard response to the floods in the Olifants River region during 2023 .................................................................115 Centennial celebration and congress of the International Union of Soil Science ..............................................................119 Suitable rootstock for soil and wine goal ..............................123 Mechanical pruning in the Orange River – a viable alternative ..................................................................126 The vine’s reserve bank ..........................................................129 PRACTICAL IN THE CELLAR The influence of consumers’ preferences on the wood character of wine .....................................................................133 What is a ‘microbiome’, and how does it relate to wine? ...134 Practical considerations concerning wine hoses .................136 Tips for additions ....................................................................138 E-aphrom – a digital sensor for secondary fermentation ......141 Organise your store .................................................................145 GENERAL Opstal Estate – rock-solid between the Slanghoek and Badsberg Mountains ..............................................................148 Carbon Heroes launches personalised QR codes and landing pages ...................................................................................149 Case study – Achtertuin Farm’s sustainability story unveiled through the CCC carbon calculator .............................152 Confronting Climate Change’s Workshops ................................155

IMAGES COPYRIGHT: Individual authors, Shutterstock or WOSA library. DTP LAYOUT: Avant-Garde South Africa | 021 863 3165 | COVER: Shutterstock, Pixabay | PRINTING: ABC Press

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TECHNICAL YEARBOOK 2024