Irrigation, to some in the world of winegrowing, is a bit of a dirty word. To others, it is seen as being absolutely essential to wine production. This is especially so in many parts of the New World, where irrigation is practiced in places that, ordinarily, wouldn’t be able to support viticulture. The grapevine is, of course, a plant and plants need water to survive.
“I don’t think irrigation is a dirty word, especially when you have the kind of climate like we have in Australia. Out of all the inputs you could use in winemaking, water is hardly toxic.”
The amount of water available to the grapevine affects photosynthesis (light energy converted to chemical energy as fuel for the plant) and, therefore, the growth of the plant, as well as the development of the fruit, is determined by the amount of water it receives. A typical grapevine requires between 600mm and 900mm of water per year, usually during the spring and summer months of the growing season. If it does not receive the requisite amount of water, the vine can, of course, die. Otherwise, the grapevine’s growth will be affected in a number of ways due to water stress, such as reduced berry size (meaning more concentrated sugars), which can lead to potentially higher alcohol levels. Too much water, however, and the berry size can increase, which can mean greater yields (increasing the potential to make and sell more wine), but usually at the expense of overall quality.
“The assumption that lower yields automatically means higher quality has been shown to be incorrect,” says Mark Davidson, chief winemaker at Tamburlaine Organic Wines, in the Hunter Valley. “Low yielding grapevines can also be of poor quality, while overcropping, on the other hand, is definitely a negative factor for wine quality. Optimum yields are key.”
In the Old World, where winegrowers have had the benefit of centuries of viticultural experimentation, natural rainfall is considered the only acceptable form of irrigation. There are strict laws within the European Union that ban the use of artificial sources of irrigation. However, in the 1990s, after long periods of drought, Spain legalised the use of simulated irrigation, which has lead to a revival of the Spanish wine industry, as well as an overall improvement in yields and wine quality. For many winegrowing regions in the New World, such as Australia and New Zealand, the wine industries here simply wouldn’t be able to survive (let alone thrive, as they have done) without the practical effects of simulated irrigation.
“Supplementary irrigation simply offsets any serious variation in water availability from season to season at key times of the annual vine growth and fruit development cycle,” explains Mark Davidson.
“I don’t think irrigation is a dirty word,” says Giles Lapalus from Sutton Grange in Victoria, “especially when you have the kind of climate like we have in Australia. Out of all the inputs you could use in winemaking, water is hardly toxic.”
The aim of irrigation is to achieve a balance between the vegetative and reproductive development of the grapevine and to limit or avoid water stress. In Australia, irrigation is seen as an integral feature of winegrowing and is often regarded as the key to improving wine quality.
“Our winegrowing business would not survive without irrigation,” says David Paxton, from Paxton Vineyards in McLaren Vale, South Australia. “Before irrigation, vineyards in the cooler areas relied on site selection. This means deep soils with adequate water holding capacity. The wine industry in Australia, then, was very small, due to the small areas that were able to sustain dry grown vineyards. Nowadays, the industry has expanded way beyond these small areas of exceptional water holding soils, and this has been enabled with irrigation.”
“Our winegrowing business would not survive without irrigation”
Over in the lush green of New Zealand, some vineyards still irrigate in order to supplement the natural rainfall, especially in places like Marlborough, where the permeability of the soils is significant and the relentless winds cause huge amounts of moisture evaporation.
“(If we didn’t irrigate) our 40 acres in the Rapaura Road region would not survive in the summer months,” says Claire Allan from Huia Vineyards, in Marlborough. “The porosity of the soil is too great… we also have the incessant wind offering 200 percent evaporation out of the soil on a daily basis. We use a drip irrigation system on our vines living in sand and rocks, otherwise the vines lose their leaves and can die due to extreme weather stress. We’ll water at night as much as possible, to avoid evaporation.”
Further south, in Central Otago, Nick Mills from Rippon says the majority of their vineyards, in Wanaka, have been dry farmed since 2002.
“Roughly 80% of Rippon’s vineyards are on their own roots and do not receive supplementary water. The roughly 20% that do receive some form of supplementary water are mostly vines in their youth (10-15 years old) and are planted in more stressed sites with increased exposure to altitude, harder soils and UV elements.”
The plan is to eventually ween these younger vineyard sites off the supplementary water source and get them to, “find their own sense of place,” says Nick.
“We would like to think our 14 year-young vines (Jeunesse), which are planted in a place of high stress will, with appropriate farming and patience, eventually get there. If they never do, however, we may have to accept that… if we only want to produce wines that truly reflect their place, then we should not have planted them there.”
Reflecting a sense of place in a wine, more commonly known as terroir, is usually the first casualty to suffer at the hands of any discussion about irrigation. To use Jamie Goode‘s definition, terroir is ‘the way that the environment of the vineyard shapes the quality of the wine.’ It is the combination of a number of factors, such as temperature, sunlight, slope, aspect, and of course, the rainfall distribution of a particular site. Many critics of simulated irrigation claim that if you can’t dry farm a vineyard, then you shouldn’t plant one in the first place. According to these critics, if irrigation has occurred by artificial means, then all notions of terroir are lost due to this perceived manipulation (it should be mentioned that terroir isn’t a marker of quality in itself, and some winegrowers’ aims aren’t to express any notion of terroir in their wines).
“I find it hard to reconcile the practice of ongoing, regular applications of water with the ambition of arriving at a wine with a true and enduring sense of place,” says Nick Mills, from Rippon.
David Paxton, from Paxton Vineyards disagrees, and thinks that his wines can still express their own unique sense of place, even with the drip irrigation systems he has in place.
“The reality is that much of the world has vineyards that are irrigated,” says David, “and there have been many examples of outstanding wines that have come from these areas… I believe we achieve an authentic sense of provenance with our wines,” continues David, “because of our biodynamic management practices and the fact that we don’t use any applications of synthetic chemicals, like fungicides and herbicides, which could be seen as manipulations of terroir.”
“I find it hard to reconcile the practice of ongoing, regular applications of water with the ambition of arriving at a wine with a true and enduring sense of place”
The use of organic and biodynamic viticultural methods will always be more beneficial to a winegrower, if they want to showcase and express terroir in their wines. The other advantage (in addition to not poisoning the environment) is that both of these farming methods will greatly improve the water holding capacity of vineyards soils, meaning that if a vineyard is irrigated in order to help it survive and flourish, then less water is inevitably used because more of it gets retained in the soil.
“We apply less water with a more successful result now, with our organic regime, than when we were conventional,” says Claire Allan from Huia,” particularly on our light fluvial soils (Raparua Road vineyard). The masses of fungi and organic matter we have in the cultivated under-story holds the water and moves it horizontally, so that more of it is available to the vine.”
Both of Ripon’s vineyards are managed biodynamically, and where the irrigated young vines are concerned, Nick believes that the considered application of the biodynamic method, along with composting, mulching and cultivation will ensure the best chance of survival for the young vineyard once the taps are turned off.
“We inoculate the land every year with life, in the form of compost. This is microflora,” says Nick,” issued from materials taken from Rippon’s environment, that process the mineral content of our land into a soluble form that the vine can gain nutrition from. This organic matter, even when almost completely ‘dry’, is made up of billions of simple, water based organisms. This is a stored form of water and can, in appropriately farmed vineyards, happily nourish the vine throughout the growing season.”
Ultimately, irrigation is only a tool and it is up to the individual winegrower to decide how they will use it.
Irrigation remains a sensitive subject that will continue to be discussed long after Nick Mill’s ‘Jeunesse’ vines have reached full maturity. However, one thing we can be sure of is that viticultures expansion throughout the New World would not have been possible without the advantages afforded to it by simulated irrigation technology to supplement rainfall variation that comes part and parcel with farming. Both Australia and New Zealand would, no doubt, be much smaller industries without it, and the quality of the wines might even be diminished too. Sustainable methods of viticulture, such as organic and biodynamic farming, ultimately improve the water holding capacity in a vineyard’s soils (agro-chemicals kill and dry out soils and increase wasteful run-off) by extending the benefits of natural rainfall as and when it occurs, while also reducing the amount and the need to irrigate in the first place.
Ultimately, irrigation is only a tool and it is up to the individual winegrower to decide how they will use it.
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D// – The Wine Idealist
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Interesting. Thanks Daniel.
Thank’s Sue. My pleasure…