Growing Futures

Predicting yield

Optimising vineyard yield

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Predicting yield

Image of grape buds close up

Weather conditions at bunch initiation (December-January) can be used to predict potential yields for the following season (March-April the following year). By measuring the average temperature approximately 15 months before harvest, growers can estimate the potential wine grape yield at harvest and manage their vineyard and postharvest logistics accordingly.

For the 2013 harvest, temperature measurements in December 2011 have led to predictions that yields will potentially be between 10 and 55% below the long-term average, depending on weather conditions during flowering in December 2012. As a result, growers are adjusting their management practices, for example retaining a greater number of buds at pruning than in previous seasons. If flowering is good in December, resulting in predictions of higher than target yields, growers can use mechanical thinning in January 2013 to moderate yield back to target.