Technical Yearbook 2023

FIGURE 4. Projected future changes in annual total rainfall (mm) (left) and annual mean temperature (°C) (right) for the period 2030 - 2060 for four “archetype” climate models representing the range of model outcomes. Figure titles are the name of the model and the area average change in rainfall or temperature. Diagonal hashing indicates trends that are not statistically significant. Source: Jack and other authors (2022).

FIGURE 5. Historical (left map) and projected future (right map, 2046 - 2065) accumulated seasonal positive chill units for the Western Cape Province. Source: Midgley and other authors (2021). HISTORICAL FUTURE

yield, as well as a range of wine styles. The role of soil health will be increasingly important to assist the plant to become resilient against climatic stresses. Practical ways of designing to harvest and reuse all rainfall water and increase the levels of water tables can be considered. The rebuilding of ‘vleilande’ or wetlands can build a biodiverse system for all kinds of insects and small animals and also increase the levels of the water tables. Mulching could be used to preserve soil moisture, avoid the use of herbicides and build soil reserves. Certain varieties could benefit from a sprawl or bush vine training system,

rather than the VSP (vertical shoot position) system. There are many ways in which the threat of climatic stresses, which could cause lower acidities and higher pH in grapes, flooding, sunburn, shrivelling of berries, etcetera could be tackled. Significance to industry The versatility of Chenin blanc, together with careful site selection, appropriate vineyard design and best viticultural practices, will allow this wonderful variety to survive and flourish well into the future, even with climate change. However, the choices made now are critical to securing a sustainable future for Chenin blanc

in South Africa and other producing countries. Abstract The Chenin blanc wine grape cultivar is adapted to a wide range of climates and soils. Climate change in the Western Cape, South Africa, is causing warmer and dryer conditions. This will impact production and berry quality, but there are many practical ways in which this threat could be tackled. A science- and data-driven approach, using available tools and analysis at multiple scales, can be matched with appropriate vineyard-level planning and practices to build resilience and ensure sustainability. 

References https://www.wineland.co.za/chenin-blanc-the-versatile-varietal/

For more information, contact Stephanie Midgley at stephanie.midgley@westerncape.gov.za.

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TECHNICAL YEARBOOK 2023