The year 2017 marks the third consecutive winter that the Western Cape of South Africa has had below average rainfall. Even though De Toren, as a producer of top quality wines, uses significantly less water compared to more commercial wineries, the effect of this drought is long term and the only way to succeed is to adapt. Winemaker Charles shares De Toren’s approach to this water crisis.
The Western Cape received 30% less rainfall in 2017 than in 2016, resulting in our dam levels only being filled to 35% capacity compared to an already low 62% the same time last year. During the recent 2017/18 growing season, the restrictions on our water allocation from the Theewaterskloof scheme, reached a very concerning low point. A further 65% reduction in the water available to us following last year’s 30% reduction. To put this into perspective, the water allocated to De Toren this year will only be enough to irrigate 9 of our 22 hectares. To make this available water stretch as far as possible across our 22 hectares, we will have to reduce our irrigation cycles to a mere 3 cycles throughout the 6 months’ growing season, in order to water each vine.
The De Toren team was fortunately more than 20 years ago, already thinking ahead. With exceptional quality in mind, drip irrigation was installed to ensure the most economic and concentrated use of our valuable water, limiting any evaporation as best possible. Flood or overhead irrigation, using masses of water has never even been part of our vocabulary. Grapes emanate from semi-desert areas after all and too much water grows diluted berries, resulting in flabby wines. From there our reductive approach when it comes to watering our vines. Quality, quality, quality – that will forever remain our core focus.
With all this being said, we still needed an even more sufficient plan of action to address this drought challenge head-on! We knew that our usual practices, processes and technology needed to be reviewed and adapted. So early 2016 already, my team and I started a very thorough research project of our own to help inform our ‘water-wise-succession-strategy.’ We re-engineered our everyday thinking and did so by working through the below areas of consideration…
The Effect of Drought in the Vineyards
The continuous drought will have some physiological manifestations. At this stage, shoot length and growth has not been compromised, however as predicted, and as observed in the vineyards now, the completion of the fruit set, i.e. the amount of berries per bunch are looking less than the norm. This is to be expected, since the plants have been living in an environment of constant water restraint for nearly 3 years and it is therefore adjusting its growth patterns and crop size to the ‘new normal’. The silver lining is that the balance in our grapes is proving to be phenomenal and in my opinion, that is the major driver of complexity and quality in wines.
This year again, I am astonished by the wonder of nature; it is remarkable to see how one element of nature can compensate for another. Vines are resilient and the season’s lower evening temperatures have allowed the vines to revitalize it-self. It is actually astonishing to observe how little water a vine needs to grow the perfect berries. Combine this with the cooling effect of the sea breeze our vines are fortunate enough to be exposed to, and the season’s very cold pre-dawn morning temperatures and you have the perfect recipe to produce grapes of exceptional quality.
Our Water Wise Action Plan for Succession
In order to use water more efficiently, it requires an in-depth look at the growth of the vines as well as the numerous aspects that can impact the plant’s water restraint to plot out a plan of action.
Herewith a summary of the strategy we have already started to implement at De Toren:
- We started by covering the soil in and around our vines with a natural layer of protection e.g. bark – anything to help keep the soil moist for as long as possible following any rainfall or irrigation.
- We will continue to make use of our economic drip irrigation system and will only irrigate on wind still evenings to avoid or limit evaporation as far as possible.
- When applying additional irrigation, we will wet the soils to a sufficiently deep level: short ‘pulse’ irrigations lead to increased losses through evaporation.
- No weeds will be allowed to grow between the vines, as these will compete with the vines for resources.
- We employ the latest plant based water monitoring system, which have allowed us to make irrigation decisions based on the level of precise dehydration in the plant at that moment in time. Through this, we can identify small, very precise areas in the vineyard which need slightly less water, based on these hydrations readings at the point in time. This way we can prioritize the areas in the vineyard where the water is most needed and plan our irrigation strategy accordingly. Read more here on our water monitoring system.
- Watering the vines only at the key phenological stages (mentioned below) to maximize the impact of the limited water available.
- Key phenological stages:
- Flowering: During this phase, the availability of enough water is crucial to transpire and encourage positive water, sugar and nutrient flow to and from the leaves and flowering inflorescence. This will result in good fruit set.
- Fruit set through to veraison: Although less sensitive than the flowering stage, water restraint should be managed to a level that allows for efficient vegetative and reproductive development. Arguably the most critical stage is veraison. At this stage the vine and berries are functioning at its peak in terms of producing phenols (colour, tannins) and precursors of aroma. It is imperative that the vines are sufficiently hydrated for this whirlpool of activity.
- Following veraison: The good news is that from after veraison the plants’ water requirements dramatically declines and we even moderate the water restraint in the vines to achieve higher quality berries.
- As previously mentioned, it is expected for the crop load to be slightly below average, this translates to the conclusion that the canopy can be more compact – canopy architecture is extremely important. New leaves transpire more, thus the ratio of new growth will be managed very precisely. The decision on when to tip or top the canopies is crucial and we will ensure perfect timing for the suckering process, since this is also an absolute necessity.
- We will not allow the development of any other shoots, besides the ones bearing fruit. These will only result in the waste of valuable nutrients, the loss of precious water through means of transpiration and it will also make canopy architecture too dense, resulting in lower grape quality.
In closing, we at De Toren have valued and appreciated the significance of water for a long time. For the past decade already, we have been using 50% less water than the norm to ensure the growth of absolutely balanced berries in order to produce complex, expressive wines of top quality. As a wine producer, water is without a doubt one of our most valuable commodities and we try our best to treat it with exceptional care and respect.