Irrigation in viticulture
Encyclopedia
The role of irrigation in viticulture is considered both controversial and essential to wine production. In the physiology
of the grapevine
, water
is a vital component to function of the vine with its presence or lack impacting photosynthesis
, new plant shoot
growth, as well as the development of grape berries. While climate
and humidity
play important roles, a typical grape vine needs 25-35 inches (635-890 millimeters) of water a year, occurring during the spring and summer months of the growing season, to avoid stress. A vine that does not receive the necessary amount of water will have its growth altered in a number of ways; some effects of water stress (particularly, smaller berry size and somewhat higher sugar content) are considered desirable by wine grape growers.
In many Old World wine
regions, natural rainfall is considered the only source for water that will still allow the vineyard to maintain its terroir
characteristics. The practice of irrigation
is viewed by some critics as unduly manipulative with the potential for detrimental wine quality due to high yields that can be artificially increased with irrigation. It has been historically banned by the European Union's wine laws, though in recent years individual countries (such as Spain) have been loosening their regulations and France's wine governing body, the Institut National des Appellations d'Origine
(INAO), has also been reviewing the issue.
In very dry climates that receive little rainfall, irrigation is considered essential to any viticultural prospects. Many New World wine
regions such as Australia and California regularly practice irrigation in areas that couldn't otherwise support viticulture. Advances and research in these wine regions (as well as some Old World wine regions such as Israel), have shown that potential wine quality could increase in areas where irrigation is kept to a minimum and managed. The main principle behind this is controlled water stress
where the vine receives sufficient water during the budding and flowering period that is then scaled back during the ripening period where the vine then responds by funneling more its limited resources into developing the grape clusters instead of excess foliage. If the vine receives too much water stress, then photosynthesis and other important process could be impacted with vine essentially shutting down. The availability of irrigation means that if drought
conditions emerge, sufficient water can be provided for the plant so that the balance between water stress and development is kept to optimal levels.
The practice of irrigation has had a long history in wine production. Archaeologists describe it as one of the oldest practices in viticulture, with irrigation canals discovered near vineyard sites in Armenia
and Egypt
dating back more than 2600 years. Irrigation was already widely practice for other agricultural crops since around 5000 BC. It is possible that the knowledge of irrigation helped viticulture spread from these areas to other regions due to the potential for the grapevine to grow in soils too infertile to support other food crops. A somewhat hardy plant, the grapevine largest need is for sufficient sunshine and is able to flourish with minimum needs of water and nutrients. In areas where its water needs are unfulfilled, the availability of irrigation meant that viticulture could still be supported.
In the 20th century, the growing wine industries of California, Australia and Israel were greatly enhanced by advances in irrigation. With the development of more cost efficient and less labor intensive ways of watering the vines, vast tracks of very sunny but dry lands were able to be converted into growing wine regions. The ability to control the precise amount of water each vine received, allowed producers in these New World wine regions to develop styles of wines that could be fairly consistent each year regardless of normal vintage
variation. This created a stark contrast to the Old World wine regions of Europe where vintage variation, including rainfall, had a pronounced effect on the potential wine style each year. Continuing research explored the way that controlled (or supplemental) irrigation could be used to increase potential wine quality by influence how the grapevine responds to its environment and funnels resources into developing the sugars, acids and phenolic compounds that contribute to a wine's quality. This research lead to the development of ways to measure the amount water retention in the soil to where individual irrigation regimes could be plotted for each vineyard that maximized the benefits of water management.
for many of the nutrients and mineral
s needed to carry out important physiological functions-which the vine receives by absorbing the nutrient-containing water from the soil. In the absence of water in the soil, the root
system of the vine may have difficulties absorbing these nutrients. Within the structure of the plant itself, water acts as a transport within the xylem
bring these nutrients to all ends of the plant. During the process of photosynthesis, water molecules combine with carbon
derived from carbon dioxide
to form glucose
which is the primary energy source of the vine as well as oxygen
as a by-product.
In addition to its use in photosynthesis, a vine's water supply is also depleted by the processes of evaporation
and transpiration
. In evaporation, heat (aided by wind
and sunlight
) causes water moisture in the soil to evaporate and escape as vapor molecules
. This process is inversely related to humidity
with evaporation often taking place at faster rates in areas with low relative humidity
. In transpiration, this evaporation of water occurs directly in the wine as water is released from the plant through the stomata that is located underneath the leafs of a grape vine. This process helps the vine combat against the effects of heat stress which can severely damage the physiological functions of the vine (somewhat similar to how perspiration works with humans and animals). The presence of adequate water in the vines can help keep the internal temperature of the leaf only a few degrees above the temperature of the surrounding air. However, if water is severely lacking then that internal temperature could jump nearly 18 °F (10 °C) warmer than the surrounding air which leads the vine to develop heat stress. The dual effects of evaporation and transpiration are called evapotranspiration
. A typical vineyard in a hot, dry climate can lose as much as 1700 US gal (6,435.2 l; 1,415.5 imp gal) of water per vine through evapotranspiration during the growing season.
There are essentially two main types irrigation-primary irrigation, which is needed for areas (such as very dry climates) that lack sufficient rainfall for viticulture to even exist, and supplemental irrigation where irrigation is used to "fill in the gaps" of natural rainfall to bring water levels to better numbers as well as to serve as a preventive measure in case of seasonal drought conditions. In both cases, both the climate and the vineyard soils of the region will play an instrumental role in irrigation's use and effectiveness.
will dictate exactly how much irrigation is needed with high levels of evapotranspiration more commonly occurring in Mediterranean climates that have low levels of humidity such as part of Chile and the Cape Province
of South Africa. In these low humidity regions, primary irrigation may be needed, but in many Mediterranean climates the irrigation is usually supplemental. The amount of precipitation that occurs during spring and summer months is also important. For example, Tuscany
receives an average of 8 inches (200 mm) of rainfall during the months of April through June - the period that includes flowering and fruit set, when the water is most crucial. While fluctuations in rainfall do occur, the amount of natural precipitation, combined with water holding capacity of soil, is typically sufficient to result in healthy harvest. In contrast, Napa Valley only gets 2.4 inches (60 mm), on average, during the same period of time, often in an erratic pattern (some years seeing more, some years seeing only trace amounts of rain), and most appellations in Central and Southern California (both along the coast and inland) receive even less than that, necessitating supplemental irrigation.
Continental climates are usually seen in areas further inland from the coastal influences of oceans and large bodies of water. The difference from the average mean temperature of its coldest and hottest months can be quite significant with moderate precipitation that usually occurs in the winter and early spring. Depending on the water retaining ability of the soil the grapevine may receive enough water during this period to last throughout the growing season with little if any irrigation needed. For soils with poor water retention, the dry summer months may require some supplemental irrigation. Examples of continental climates that use supplemental irrigation include the Columbia Valley of Washington State and the Mendoza wine
region of Argentina.
Maritime climates tend to fall between Mediterranean and continental climates with a moderate climate that is tempered by the effects of a large body of water nearby. As with Mediterranean climates, the humidity of the particular macroclimate will play a significant role in determining how much irrigation is needed. In most cases irrigation, if it is used at all, will only be supplemental in years where drought may be an issue. Many maritime regions, such as Rias Baixas
in Galicia, Bordeaux and the Willamette Valley in Oregon, suffer from the diametric problem of having too much rain during the growing season.
and viticulturist are not exactly sure what type of immutable or terroir based qualities that soil can impart on wine, there is near universal agreement that a soil's water retention
and drainage
abilities play a primary role. Water retention refers to the soil's ability to hold water. The term "field capacity" is used to describe the maximum amount of water that deeply moistened soil will retain after normal drainage. Drainage is the ability of water to move freely throughout the soil. The ideal circumstance is soil that can retain sufficient amount of water for the grapevine but drains well enough to where the soil doesn't become water-logged
. Soil that doesn't retain water well encourages the vine to easily sleep into water stress while soil that doesn't drain well runs of the risk of water-logged roots being attacked by microbial agents that consume all the soil nutrients and end up starving the vine.
The depth, texture
and composition
of soils can influence its water retaining and draining ability. Soils containing large amounts of organic material tend to have the highest water retention abilities. These types of soils include deep loams, silt
y soils like what is typically found on the fertile valley floors such as in the California's Napa Valley. Clay
particles have the potential to remain in colloidal suspension for long periods of time when it is dissolved in water. This gives clay-based soils the potential to retain significant amount of water such as the clay soils of the Right bank Bordeaux region of Pomerol. Many regions with these types of water retaining soils have little need for irrigation, or if they do it is usually supplemental during periods of drought. Soils with poor water retention include sand
and alluvial gravel
based soils such as those found in the Barolo
and Barbaresco
zones of Italy or in many areas of South Australia. Depending on the climate and amount of natural rainfall, areas with poor water retention may need irrigation.
Just as having too little water is detrimental to the grapevine, so too is having too much. When vines become water-logged they become a target for various microbial agents such as bacteria
and fungi that compete with the vine for nutrients in the soil. Additionally excessively moist soil is poor conductor of valuable heat radiating from the ground. In general wet soils are cold soils which can be especially problematic during the flowering causing poor berry set that could lead to coulure
. It also becomes an issue during the ripening stage when vines in cool-climate regions may need additional heat radiated from the ground in order to sufficiently ripen its fruit (an example of this is the slate
-based vineyards of the Mosel in Germany). Therefore, well draining soils are considered very conducive to producing quality wine. In general light-textured (such as sand and gravel) and stony soils tend to drain well. Soils heavy soils and those with high proportions of organic matter also have the potential to drain well if they having a crumbling texture and structure. This texture relates to the friability
of the soil which can come from earthworms and other organisms that have burrowed tunnels throughout the soil. Much like rocks, these tunnels give water a freer passageway through soil and contributes to its drainage.
may be moist while the surface soil appears dry. More specific measurements can be attained by using tensiometers which evaluates surface tension
of water extracted from the soil. The presence of water in the soil can be measured by neutron moisture meters that utilize an aluminium
tube with an internal neutron source that detect the subtle change between the water in the soil. Similarly, gypsum
block placed throughout the vineyard contain an electrode
that can be used to detect the electrical resistance that occurs as the soil dries and water is released by evaporation. Since the 1990s there has been greater research into tools utilizing time-domain reflectometry
and capacitance
probes. In addition to monitoring for excessive moisture, viticulturists also keep an eye for signs of water stress (discussed below) due to severe lack of water.
was the most common means using the gravity of a slope to release a flood of water across the vineyard. In the early history of the Chilean wine industry, flood irrigation was widely practiced in the vineyards using melted snow from the Andes Mountains channeled down to the valleys below. This method provided very little control and often had the adverse effect of over-watering the vine. An adaption of method was the furrow irrigation system used in Argentina where small channels ran through the vineyard providing irrigation. This provide slightly more control since the initial amount of water entering the channels could be regulated, however the amount that each vine received was sporadic.
Sprinkler irrigation involves the installation of a series of sprinkler units throughout the vineyard, often spaced as several rows about 65 feet (20 m) apart. The sprinklers can be set on a electronic timer and release predetermined amount of water for a set period of time. While this provides more control and uses less water than flood irrigation, like furrow irrigation the amount that each individual wine receives can be sporadic. The irrigation system that provides the most control over water management, though conversely the most expensive to install, is drip irrigation
. This system involved long plastic water supply lines that run down each row of vines in the vineyard with each individual grape vine having its own individual dripper. With this system, a viticulturist can control the precise amount of water that each grapevine gets down to the drop. An adaption of this system, potentially useful in areas where irrigation may be banned, is underground subirrigation
where precise measurements of water is delivered directly to the root system.
With abundant water, a grapevine will produce shallow root systems and vigorous growths of new plant shoots. This can contribute to a large, leafy canopy
and high yields of large grape berry clusters that may not be sufficiently or physiologically ripe. With insufficient water, many of the vine's important physiological structures, including photosynthesis that contributes to the development of sugars and phenolic compounds in the grape, can shut down. The key to irrigation is to provide just enough water for the plant to continuing function without encouraging vigorous growth of new shoots and shallow roots. The exact amount of water will depend on a variety of factors including how much natural rainfall can be expected as well as the water retaining and drainage properties of the soil.
Water is very crucial during the early budding
and flowering stages of the growing season
. In areas where there is not sufficient rainfall, irrigation may be needed during this time in the spring. After fruit set, the water needs for the vine drop and irrigation is often withheld till the period of veraison
when the grapes begin to change color. This period of "water stress" encourages the vine to concentrate its limited resources into lower yields of smaller berries creating a favorable skin to juice ratio that is often desirable in quality wine production. The benefits or disadvantages of irrigation during the ripening period itself is a matter of debate and continuing research in the wine growing community. The only area of mostly agreement is the disadvantages of water close to harvest
after a prolong dry period. Grapevines that has been subjugated to prolong water stress have a tendency to rapidly absorb large amounts of water if its provided. This will dramatically swell the berries, potentially causing to them crack or burst which will make the prone to various grape diseases. Even if the berries do not crack or burst, the rapid swelling of water will cause a reduce concentration in sugars and phenolic compounds in the grape producing wines with diluted flavors and aromas.
The term water stress describes the physiological states that grapevines experience when they are deprived of water. When a grapevine goes into water stress one of its first functions is to reduce the growth of new plant shoots which compete with the grape clusters for nutrients and resources. The lack of water also keeps the individual grape berries down to a smaller size which increase its skin to juice ratio. As the skin is filled with color phenol
s, tannin and aroma compounds, the increase skin to juice ratio is desirable for the potential added complexity the wine may have. While there is disagreement over exactly how much water stress if beneficial in development grapes for quality wine production, most viticulturist agree that some water stress can be beneficial. The grapevines in many Mediterranean climates such as Tuscany in Italy and the Rhone Valley in France experience natural water stress due to the reduced rainfall that occurs during the summer growing season.
At the far extreme is severe water stress which can have detrimental effects on both the vine and on potential wine quality. To conserve water, a vine will try to conserve water by limiting its lose through transpiration. The plant hormone abscisic acid
triggers the stomata on the underside of the plant leaf to stay close in order to reduce the amount of water that is evaporated. While conserving water this also has the consequences of limiting the intake of carbon dioxide needed to sustain photosynthesis. If the vine is continually stressed it will keeps it stomata closed for longer and longer periods of time which can eventually cause photosynthesis to stop all together. When a vine has been so deprived of water it can exceed what is known as its permanent wilting point
. At this point, the vine can become permanently damaged beyond recovery even if later watered. Viticulturists will carefully watch the plant for signs of severe water stress. Some of the symptoms include:
The effectiveness of water stress is an area of continuing research in viticulture. Of particular focus is the connection between yield size and the potential benefits of water stress. Since the act of stressing the vine does contribute to reduce photosynthesis-and by extension, reduce ripening since the sugars produced by photosynthesis is needed for grape development-it is possible that a stressed vine with high yields will only produce lots of under ripe grapes. Another interest of study is the potential impact on white grape varieties with enologists and viticulturists such as Cornelius Van Leeuwen and Catherine Peyrot Des Gachons contending that white grape varieties lose some of their aromatic qualities when subjugated to even mild forms of water stress.
that triggers some of the vine's physiological responses to water stress - reduced shoot growth, smaller berries size, etc. But because the vine is still receiving water on the other side the stress doesn't become so severe to where vital functions such as photosynthesis is compromised.
Partial rootzone drying has been shown to significantly increase a vine's water use efficiency. While PRD is shown to slightly reduce leaf area, this is generally not a problem as overall yield is unaffected.
in the land as well as the unique characteristics that comes with vintage
variation. In regions that do not practice irrigation, the quality and styles of wines can be dramatically different from vintage to vintage depending on weather conditions and rainfall. Irrigation's contribution to the broader globalization of wine
is criticized as promoting a homogenization or "standardization" of wine.
Other criticisms center around the broader environmental impact of irrigation on both the ecosystem
around the vineyard as well as the added strain on global water resources
. While advances in drip irrigation has reduced the amount of waste water produced by irrigation, the irrigation of substantial tracts of land in areas like the San Joaquin Valley
in California and the Murray-Darling Basin
of Australia requires massive amounts of water from dwindling supplies. In Australia, the centuries old practice of flood irrigation used in places like the Murrumbidgee Irrigation Area
caused severe environmental damages from water-logging, increase salination and raising the water table
s. In 2000, the Australian government invested over A$3.6 million into research on how to minimize the damage caused by extensive irrigation. In 2007, concerns about ecological damage to the Russian River
caused government officials in California to take similar measures to cut back water supplies and promote more efficient irrigation practices.
with water in a process known as fertigation
. Commonly used in drip irrigation systems, this method allows similarly regulate control over how precisely how much fertilizer and nutrients that each vine receives. Another alternative use for sprinkler irrigation systems can occur during the threat of winter or spring time frost. When temperature drop below 32 °F (0 °C), the vine is at risk of developing frost damage that could not only ruining the upcoming years harvest but also kill the vine. One preventive measure against frost damage is to use the sprinkler irrigation system to coat the vines with a protective layer of water that freezes into ice. This layer of ice serves as insulation keeping the internal temperature of the vine from dropping below the freezing mark.
Physiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...
of the grapevine
Grapevine
Grapevine is the common name for plants of the genus Vitis. Other meanings include:*Grapevine , a term often used to describe a form of communication by means of gossip or rumor, as in "heard it through the grapevine"...
, water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
is a vital component to function of the vine with its presence or lack impacting photosynthesis
Photosynthesis
Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...
, new plant shoot
Shoot
Shoots are new plant growth, they can include stems, flowering stems with flower buds, and leaves. The new growth from seed germination that grows upward is a shoot where leaves will develop...
growth, as well as the development of grape berries. While climate
Climate
Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...
and humidity
Humidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...
play important roles, a typical grape vine needs 25-35 inches (635-890 millimeters) of water a year, occurring during the spring and summer months of the growing season, to avoid stress. A vine that does not receive the necessary amount of water will have its growth altered in a number of ways; some effects of water stress (particularly, smaller berry size and somewhat higher sugar content) are considered desirable by wine grape growers.
In many Old World wine
Old World wine
Old World wine refers primarily to wine made in Europe but can also include other regions of the Mediterranean basin with long histories of winemaking such as North Africa and the Near East. The phrase is often used in contrast to "New World wine" which refers primarily to wines from New World wine...
regions, natural rainfall is considered the only source for water that will still allow the vineyard to maintain its terroir
Terroir
Terroir comes from the word terre "land". It was originally a French term in wine, coffee and tea used to denote the special characteristics that the geography, geology and climate of a certain place bestowed upon particular varieties...
characteristics. The practice of irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...
is viewed by some critics as unduly manipulative with the potential for detrimental wine quality due to high yields that can be artificially increased with irrigation. It has been historically banned by the European Union's wine laws, though in recent years individual countries (such as Spain) have been loosening their regulations and France's wine governing body, the Institut National des Appellations d'Origine
Institut National des Appellations d'Origine
The Institut National des Appellations d'Origine is the French organization charged with regulating French agricultural products with Protected Designations of Origin . Controlled by the French government, it forms part of the Ministry of Agriculture...
(INAO), has also been reviewing the issue.
In very dry climates that receive little rainfall, irrigation is considered essential to any viticultural prospects. Many New World wine
New World wine
New World wines are those wines produced outside the traditional wine-growing areas of Europe, in particular from Argentina, Australia, Canada, Chile, New Zealand, South Africa and the United States.-Early wines in the Americas:...
regions such as Australia and California regularly practice irrigation in areas that couldn't otherwise support viticulture. Advances and research in these wine regions (as well as some Old World wine regions such as Israel), have shown that potential wine quality could increase in areas where irrigation is kept to a minimum and managed. The main principle behind this is controlled water stress
Water stress
Researchers define water stress and water scarcity in different ways. For example, some have presented maps showing the physical existence of water in nature to show nations with lower or higher volumes of water available for use. Others have related water availability to population...
where the vine receives sufficient water during the budding and flowering period that is then scaled back during the ripening period where the vine then responds by funneling more its limited resources into developing the grape clusters instead of excess foliage. If the vine receives too much water stress, then photosynthesis and other important process could be impacted with vine essentially shutting down. The availability of irrigation means that if drought
Drought
A drought is an extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region...
conditions emerge, sufficient water can be provided for the plant so that the balance between water stress and development is kept to optimal levels.
History
Armenia
Armenia , officially the Republic of Armenia , is a landlocked mountainous country in the Caucasus region of Eurasia...
and Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...
dating back more than 2600 years. Irrigation was already widely practice for other agricultural crops since around 5000 BC. It is possible that the knowledge of irrigation helped viticulture spread from these areas to other regions due to the potential for the grapevine to grow in soils too infertile to support other food crops. A somewhat hardy plant, the grapevine largest need is for sufficient sunshine and is able to flourish with minimum needs of water and nutrients. In areas where its water needs are unfulfilled, the availability of irrigation meant that viticulture could still be supported.
In the 20th century, the growing wine industries of California, Australia and Israel were greatly enhanced by advances in irrigation. With the development of more cost efficient and less labor intensive ways of watering the vines, vast tracks of very sunny but dry lands were able to be converted into growing wine regions. The ability to control the precise amount of water each vine received, allowed producers in these New World wine regions to develop styles of wines that could be fairly consistent each year regardless of normal vintage
Vintage
Vintage, in wine-making, is the process of picking grapes and creating the finished product . A vintage wine is one made from grapes that were all, or primarily, grown and harvested in a single specified year. In certain wines, it can denote quality, as in Port wine, where Port houses make and...
variation. This created a stark contrast to the Old World wine regions of Europe where vintage variation, including rainfall, had a pronounced effect on the potential wine style each year. Continuing research explored the way that controlled (or supplemental) irrigation could be used to increase potential wine quality by influence how the grapevine responds to its environment and funnels resources into developing the sugars, acids and phenolic compounds that contribute to a wine's quality. This research lead to the development of ways to measure the amount water retention in the soil to where individual irrigation regimes could be plotted for each vineyard that maximized the benefits of water management.
Role of water in viticulture
The presence of water is essential for the survival of all plant life. In a grapevine, water acts as a universal solventUniversal solvent
Universal solvent may refer to:*Water*Alkahest, a hypothetical solvent able to dissolve every other substance*The Universal Solvent, a comic by Don Rosa...
for many of the nutrients and mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
s needed to carry out important physiological functions-which the vine receives by absorbing the nutrient-containing water from the soil. In the absence of water in the soil, the root
Root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...
system of the vine may have difficulties absorbing these nutrients. Within the structure of the plant itself, water acts as a transport within the xylem
Xylem
Xylem is one of the two types of transport tissue in vascular plants. . The word xylem is derived from the Classical Greek word ξυλον , meaning "wood"; the best-known xylem tissue is wood, though it is found throughout the plant...
bring these nutrients to all ends of the plant. During the process of photosynthesis, water molecules combine with carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
derived from carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
to form glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
which is the primary energy source of the vine as well as oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
as a by-product.
In addition to its use in photosynthesis, a vine's water supply is also depleted by the processes of evaporation
Evaporation
Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....
and transpiration
Transpiration
Transpiration is a process similar to evaporation. It is a part of the water cycle, and it is the loss of water vapor from parts of plants , especially in leaves but also in stems, flowers and roots. Leaf surfaces are dotted with openings which are collectively called stomata, and in most plants...
. In evaporation, heat (aided by wind
Wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...
and sunlight
Sunlight
Sunlight, in the broad sense, is the total frequency spectrum of electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the Earth's atmosphere, and solar radiation is obvious as daylight when the Sun is above the horizon.When the direct solar radiation is not blocked...
) causes water moisture in the soil to evaporate and escape as vapor molecules
Water vapor
Water vapor or water vapour , also aqueous vapor, is the gas phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Under typical atmospheric conditions, water vapor is continuously...
. This process is inversely related to humidity
Humidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...
with evaporation often taking place at faster rates in areas with low relative humidity
Relative humidity
Relative humidity is a term used to describe the amount of water vapor in a mixture of air and water vapor. It is defined as the partial pressure of water vapor in the air-water mixture, given as a percentage of the saturated vapor pressure under those conditions...
. In transpiration, this evaporation of water occurs directly in the wine as water is released from the plant through the stomata that is located underneath the leafs of a grape vine. This process helps the vine combat against the effects of heat stress which can severely damage the physiological functions of the vine (somewhat similar to how perspiration works with humans and animals). The presence of adequate water in the vines can help keep the internal temperature of the leaf only a few degrees above the temperature of the surrounding air. However, if water is severely lacking then that internal temperature could jump nearly 18 °F (10 °C) warmer than the surrounding air which leads the vine to develop heat stress. The dual effects of evaporation and transpiration are called evapotranspiration
Evapotranspiration
Evapotranspiration is a term used to describe the sum of evaporation and plant transpiration from the Earth's land surface to atmosphere. Evaporation accounts for the movement of water to the air from sources such as the soil, canopy interception, and waterbodies...
. A typical vineyard in a hot, dry climate can lose as much as 1700 US gal (6,435.2 l; 1,415.5 imp gal) of water per vine through evapotranspiration during the growing season.
Factors influencing irrigation
Impact of different climate types
Viticulture is most commonly found in Mediterranean, continental and maritime climates with each unique climate providing its own challenges in providing sufficient water at critical times during the growing season. In Mediterranean climates irrigation is usually needed during the very dry periods of the summer ripening stages where drought can be a persistent threat. The level of humidity in a particular macroclimateMacroclimate
In viticulture, there are several levels of regional climates that are used to describe the terroir or immutable characteristics of an area. These levels can be as broad as a macroclimate which includes entire wine regions or as small as a microclimate which includes the unique environment around...
will dictate exactly how much irrigation is needed with high levels of evapotranspiration more commonly occurring in Mediterranean climates that have low levels of humidity such as part of Chile and the Cape Province
Cape Province
The Province of the Cape of Good Hope was a province in the Union of South Africa and subsequently the Republic of South Africa...
of South Africa. In these low humidity regions, primary irrigation may be needed, but in many Mediterranean climates the irrigation is usually supplemental. The amount of precipitation that occurs during spring and summer months is also important. For example, Tuscany
Tuscany
Tuscany is a region in Italy. It has an area of about 23,000 square kilometres and a population of about 3.75 million inhabitants. The regional capital is Florence ....
receives an average of 8 inches (200 mm) of rainfall during the months of April through June - the period that includes flowering and fruit set, when the water is most crucial. While fluctuations in rainfall do occur, the amount of natural precipitation, combined with water holding capacity of soil, is typically sufficient to result in healthy harvest. In contrast, Napa Valley only gets 2.4 inches (60 mm), on average, during the same period of time, often in an erratic pattern (some years seeing more, some years seeing only trace amounts of rain), and most appellations in Central and Southern California (both along the coast and inland) receive even less than that, necessitating supplemental irrigation.
Continental climates are usually seen in areas further inland from the coastal influences of oceans and large bodies of water. The difference from the average mean temperature of its coldest and hottest months can be quite significant with moderate precipitation that usually occurs in the winter and early spring. Depending on the water retaining ability of the soil the grapevine may receive enough water during this period to last throughout the growing season with little if any irrigation needed. For soils with poor water retention, the dry summer months may require some supplemental irrigation. Examples of continental climates that use supplemental irrigation include the Columbia Valley of Washington State and the Mendoza wine
Mendoza wine
The Mendoza Province is one of Argentina's most important wine regions, accounting for nearly two-thirds of the country's entire wine production. Located in the eastern foothills of the Andes, in the shadow of Mount Aconcagua, vineyards are planted at the some of the highest altitudes in the world...
region of Argentina.
Maritime climates tend to fall between Mediterranean and continental climates with a moderate climate that is tempered by the effects of a large body of water nearby. As with Mediterranean climates, the humidity of the particular macroclimate will play a significant role in determining how much irrigation is needed. In most cases irrigation, if it is used at all, will only be supplemental in years where drought may be an issue. Many maritime regions, such as Rias Baixas
Rías Baixas (DO)
Rías Baixas is a Spanish Denominación de Origen for wines located in the province of Pontevedra and the south of the province of A Coruña in the autonomous community of Galicia, Spain...
in Galicia, Bordeaux and the Willamette Valley in Oregon, suffer from the diametric problem of having too much rain during the growing season.
Impact of different soil types
Soil can have a significant impact on the potential quality of wine. While geologistGeologist
A geologist is a scientist who studies the solid and liquid matter that constitutes the Earth as well as the processes and history that has shaped it. Geologists usually engage in studying geology. Geologists, studying more of an applied science than a theoretical one, must approach Geology using...
and viticulturist are not exactly sure what type of immutable or terroir based qualities that soil can impart on wine, there is near universal agreement that a soil's water retention
Water retention curve
Water retention curve is the relationship between the water content, θ, and the soil water potential, ψ. This curve is characteristic for different types of soil, and is also called the soil moisture characteristic....
and drainage
Drainage
Drainage is the natural or artificial removal of surface and sub-surface water from an area. Many agricultural soils need drainage to improve production or to manage water supplies.-Early history:...
abilities play a primary role. Water retention refers to the soil's ability to hold water. The term "field capacity" is used to describe the maximum amount of water that deeply moistened soil will retain after normal drainage. Drainage is the ability of water to move freely throughout the soil. The ideal circumstance is soil that can retain sufficient amount of water for the grapevine but drains well enough to where the soil doesn't become water-logged
Waterlogging (agriculture)
Waterlogging refers to the saturation of soil with water. Soil may be regarded as waterlogged when the water table of the groundwater is too high to conveniently permit an anticipated activity, like agriculture....
. Soil that doesn't retain water well encourages the vine to easily sleep into water stress while soil that doesn't drain well runs of the risk of water-logged roots being attacked by microbial agents that consume all the soil nutrients and end up starving the vine.
The depth, texture
Soil texture
Soil texture is a qualitative classification tool used in both the field and laboratory to determine classes for agricultural soils based on their physical texture. The classes are distinguished in the field by the 'textural feel' which can be further clarified by separating the relative...
and composition
Soil type
In terms of soil texture, soil type usually refers to the different sizes of mineral particles in a particular sample. Soil is made up in part of finely ground rock particles, grouped according to size as sand, silt and clay...
of soils can influence its water retaining and draining ability. Soils containing large amounts of organic material tend to have the highest water retention abilities. These types of soils include deep loams, silt
Silt
Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...
y soils like what is typically found on the fertile valley floors such as in the California's Napa Valley. Clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
particles have the potential to remain in colloidal suspension for long periods of time when it is dissolved in water. This gives clay-based soils the potential to retain significant amount of water such as the clay soils of the Right bank Bordeaux region of Pomerol. Many regions with these types of water retaining soils have little need for irrigation, or if they do it is usually supplemental during periods of drought. Soils with poor water retention include sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
and alluvial gravel
Gravel
Gravel is composed of unconsolidated rock fragments that have a general particle size range and include size classes from granule- to boulder-sized fragments. Gravel can be sub-categorized into granule and cobble...
based soils such as those found in the Barolo
Barolo
Barolo is a red Denominazione di Origine Controllata e Garantita wine produced in the northern Italian region of Piedmont. It is made from the Nebbiolo grape and is often described as one of Italy's greatest wines...
and Barbaresco
Barbaresco
Barbaresco is an Italian wine made with the Nebbiolo grape. Barbaresco is produced in the Piedmont region in an area of the Langhe immediately to the east of Alba and specifically in the comunes of Barbaresco, Treiso and Neive plus that area of the frazione San Rocco Senodelvio which was once part...
zones of Italy or in many areas of South Australia. Depending on the climate and amount of natural rainfall, areas with poor water retention may need irrigation.
Just as having too little water is detrimental to the grapevine, so too is having too much. When vines become water-logged they become a target for various microbial agents such as bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
and fungi that compete with the vine for nutrients in the soil. Additionally excessively moist soil is poor conductor of valuable heat radiating from the ground. In general wet soils are cold soils which can be especially problematic during the flowering causing poor berry set that could lead to coulure
Coulure
Coulure is a potential viticultural hazard that is the result of metabolic reactions to weather conditions that causes a failure of grapes to develop after flowering. In English the word shatter is sometimes used. Coulure is triggered by periods of cold, cloudy, rainy weather or very high...
. It also becomes an issue during the ripening stage when vines in cool-climate regions may need additional heat radiated from the ground in order to sufficiently ripen its fruit (an example of this is the slate
Slate
Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism. The result is a foliated rock in which the foliation may not correspond to the original sedimentary layering...
-based vineyards of the Mosel in Germany). Therefore, well draining soils are considered very conducive to producing quality wine. In general light-textured (such as sand and gravel) and stony soils tend to drain well. Soils heavy soils and those with high proportions of organic matter also have the potential to drain well if they having a crumbling texture and structure. This texture relates to the friability
Friability
Friability is the ability of a solid substance to be reduced to smaller pieces with little effort. The opposite of friable is indurated....
of the soil which can come from earthworms and other organisms that have burrowed tunnels throughout the soil. Much like rocks, these tunnels give water a freer passageway through soil and contributes to its drainage.
Measuring soil moisture
Because of the problems associated with water-logged and wet soils, it is important for viticulturist to know how much water is currently in the soil before deciding if and how much to irrigate. There are several methods of evaluating soil moisture. The most basic is simple observation and feeling of the soil, however this has its limitations since the subsoilSubsoil
Subsoil, or substrata, is the layer of soil under the topsoil on the surface of the ground. The subsoil may include substances such as clay and/or sand that has only been partially broken down by air, sunlight, water, wind etc., to produce true soil...
may be moist while the surface soil appears dry. More specific measurements can be attained by using tensiometers which evaluates surface tension
Surface tension
Surface tension is a property of the surface of a liquid that allows it to resist an external force. It is revealed, for example, in floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects to run on the water surface...
of water extracted from the soil. The presence of water in the soil can be measured by neutron moisture meters that utilize an aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
tube with an internal neutron source that detect the subtle change between the water in the soil. Similarly, gypsum
Gypsum
Gypsum is a very soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is found in alabaster, a decorative stone used in Ancient Egypt. It is the second softest mineral on the Mohs Hardness Scale...
block placed throughout the vineyard contain an electrode
Electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit...
that can be used to detect the electrical resistance that occurs as the soil dries and water is released by evaporation. Since the 1990s there has been greater research into tools utilizing time-domain reflectometry
Time-domain reflectometry
Time-domain reflectometry or TDR is a measurement technique used to determine the characteristics of electrical lines by observing reflected waveforms. Time-domain transmissometry is an analogous technique that measures the transmitted impulse...
and capacitance
Capacitance
In electromagnetism and electronics, capacitance is the ability of a capacitor to store energy in an electric field. Capacitance is also a measure of the amount of electric potential energy stored for a given electric potential. A common form of energy storage device is a parallel-plate capacitor...
probes. In addition to monitoring for excessive moisture, viticulturists also keep an eye for signs of water stress (discussed below) due to severe lack of water.
Irrigation systems
There are several methods of irrigation that can be used in viticulture depending on the amount of control and water management desired. Historically, surface irrigationSurface irrigation
Surface irrigation is defined as the group of application techniques where water is applied and distributed over the soil surface by gravity. It is by far the most common form of irrigation throughout the world and has been practiced in many areas virtually unchanged for thousands of years.Surface...
was the most common means using the gravity of a slope to release a flood of water across the vineyard. In the early history of the Chilean wine industry, flood irrigation was widely practiced in the vineyards using melted snow from the Andes Mountains channeled down to the valleys below. This method provided very little control and often had the adverse effect of over-watering the vine. An adaption of method was the furrow irrigation system used in Argentina where small channels ran through the vineyard providing irrigation. This provide slightly more control since the initial amount of water entering the channels could be regulated, however the amount that each vine received was sporadic.
Sprinkler irrigation involves the installation of a series of sprinkler units throughout the vineyard, often spaced as several rows about 65 feet (20 m) apart. The sprinklers can be set on a electronic timer and release predetermined amount of water for a set period of time. While this provides more control and uses less water than flood irrigation, like furrow irrigation the amount that each individual wine receives can be sporadic. The irrigation system that provides the most control over water management, though conversely the most expensive to install, is drip irrigation
Drip irrigation
Drip irrigation, also known as trickle irrigation or microirrigation or localized irrigation , is an irrigation method which saves water and fertilizer by allowing water to drip slowly to the roots of plants, either onto the soil surface or directly onto the root zone, through a network of valves,...
. This system involved long plastic water supply lines that run down each row of vines in the vineyard with each individual grape vine having its own individual dripper. With this system, a viticulturist can control the precise amount of water that each grapevine gets down to the drop. An adaption of this system, potentially useful in areas where irrigation may be banned, is underground subirrigation
Subirrigation
In agriculture, subirrigation, also known as seepage irrigation, is a method of irrigation where water is delivered to the plant root zone from below the soil surface and absorbed upwards...
where precise measurements of water is delivered directly to the root system.
When and how much?
Canopy (vine)
In viticulture, the canopy of a grapevine includes the parts of the vine visible aboveground - the trunk, cordon, stems, leaves, flowers, and fruit. The canopy plays a key role in light energy capture via photosynthesis, water use as regulated by transpiration, and microclimate of ripening grapes...
and high yields of large grape berry clusters that may not be sufficiently or physiologically ripe. With insufficient water, many of the vine's important physiological structures, including photosynthesis that contributes to the development of sugars and phenolic compounds in the grape, can shut down. The key to irrigation is to provide just enough water for the plant to continuing function without encouraging vigorous growth of new shoots and shallow roots. The exact amount of water will depend on a variety of factors including how much natural rainfall can be expected as well as the water retaining and drainage properties of the soil.
Water is very crucial during the early budding
Budding
Budding is a form of asexual reproduction in which a new organism grows on another one. The new organism remains attached as it grows, separating from the parent organism only when it is mature. Since the reproduction is asexual, the newly created organism is a clone and is genetically identical...
and flowering stages of the growing season
Growing season
In botany, horticulture, and agriculture the growing season is the period of each year when native plants and ornamental plants grow; and when crops can be grown....
. In areas where there is not sufficient rainfall, irrigation may be needed during this time in the spring. After fruit set, the water needs for the vine drop and irrigation is often withheld till the period of veraison
Veraison
Véraison is a viticulture term meaning "the onset of ripening". It is originally French, but has been adopted into English use...
when the grapes begin to change color. This period of "water stress" encourages the vine to concentrate its limited resources into lower yields of smaller berries creating a favorable skin to juice ratio that is often desirable in quality wine production. The benefits or disadvantages of irrigation during the ripening period itself is a matter of debate and continuing research in the wine growing community. The only area of mostly agreement is the disadvantages of water close to harvest
Harvest (wine)
The harvesting of wine grapes is one of the most crucial steps in the process of winemaking. The time of harvest is determined primarily by the ripeness of the grape as measured by sugar, acid and tannin levels with winemakers basing their decision to pick based on the style of wine they wish to...
after a prolong dry period. Grapevines that has been subjugated to prolong water stress have a tendency to rapidly absorb large amounts of water if its provided. This will dramatically swell the berries, potentially causing to them crack or burst which will make the prone to various grape diseases. Even if the berries do not crack or burst, the rapid swelling of water will cause a reduce concentration in sugars and phenolic compounds in the grape producing wines with diluted flavors and aromas.
Water stress
Phenolic compounds in wine
The phenolic compounds - natural phenol and polyphenols - in wine include a large group of several hundred chemical compounds that affect the taste, color and mouthfeel of wine. These compounds include phenolic acids, stilbenes, flavonols, dihydroflavonols, anthocyanins, flavanol monomers and...
s, tannin and aroma compounds, the increase skin to juice ratio is desirable for the potential added complexity the wine may have. While there is disagreement over exactly how much water stress if beneficial in development grapes for quality wine production, most viticulturist agree that some water stress can be beneficial. The grapevines in many Mediterranean climates such as Tuscany in Italy and the Rhone Valley in France experience natural water stress due to the reduced rainfall that occurs during the summer growing season.
At the far extreme is severe water stress which can have detrimental effects on both the vine and on potential wine quality. To conserve water, a vine will try to conserve water by limiting its lose through transpiration. The plant hormone abscisic acid
Abscisic acid
Abscisic acid , also known as abscisin II and dormin, is a plant hormone. ABA functions in many plant developmental processes, including bud dormancy. It is degraded by the enzyme -abscisic acid 8'-hydroxylase.-Function:...
triggers the stomata on the underside of the plant leaf to stay close in order to reduce the amount of water that is evaporated. While conserving water this also has the consequences of limiting the intake of carbon dioxide needed to sustain photosynthesis. If the vine is continually stressed it will keeps it stomata closed for longer and longer periods of time which can eventually cause photosynthesis to stop all together. When a vine has been so deprived of water it can exceed what is known as its permanent wilting point
Permanent wilting point
Permanent wilting point or wilting point is defined as the minimal point of soil moisture the plant requires not to wilt. If moisture decreases to this or any lower point a plant wilts and can no longer recover its turgidity when placed in a saturated atmosphere for 12 hours...
. At this point, the vine can become permanently damaged beyond recovery even if later watered. Viticulturists will carefully watch the plant for signs of severe water stress. Some of the symptoms include:
- Flaccid and wiltingWiltingWilting refers to the loss of rigidity of non-woody parts of plants. This occurs when the turgor pressure in non-lignified plant cells falls towards zero, as a result of diminished water in the cells...
tendrilsTendrilsTendrils is an irregular collaboration between noted Australian guitarists, Joel Silbersher and Charlie Owen. A difficult sound to describe, Tendrils features two seemingly chaotic but strangely melodic and complementary, guitar parts and occasionally stripped back percussion.Starting out billed... - (During Flowering) Flower clusters that are dried out
- Wilting of young grape leaves followed by maturer leaves
- Chlorosis signaling that photosynthesis has stopped
- NecrosisNecrosisNecrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
of dying leaf tissue which leads to premature leaf fall - Finally, the grape berries themselves start to shrivel and fall off the vine
The effectiveness of water stress is an area of continuing research in viticulture. Of particular focus is the connection between yield size and the potential benefits of water stress. Since the act of stressing the vine does contribute to reduce photosynthesis-and by extension, reduce ripening since the sugars produced by photosynthesis is needed for grape development-it is possible that a stressed vine with high yields will only produce lots of under ripe grapes. Another interest of study is the potential impact on white grape varieties with enologists and viticulturists such as Cornelius Van Leeuwen and Catherine Peyrot Des Gachons contending that white grape varieties lose some of their aromatic qualities when subjugated to even mild forms of water stress.
Partial rootzone drying
One irrigation technique known as partial rootzone drying (or PRD) involves "tricking" the grapevine into thinking it is undergoing water stress when it is actually receiving sufficient water supply. This is accomplished by alternating drip irrigation to where only one side of the grapevine receives water at a time. The roots on the dry side of the vine produce abscisic acidAbscisic acid
Abscisic acid , also known as abscisin II and dormin, is a plant hormone. ABA functions in many plant developmental processes, including bud dormancy. It is degraded by the enzyme -abscisic acid 8'-hydroxylase.-Function:...
that triggers some of the vine's physiological responses to water stress - reduced shoot growth, smaller berries size, etc. But because the vine is still receiving water on the other side the stress doesn't become so severe to where vital functions such as photosynthesis is compromised.
Partial rootzone drying has been shown to significantly increase a vine's water use efficiency. While PRD is shown to slightly reduce leaf area, this is generally not a problem as overall yield is unaffected.
Criticism and environmental issues
The practice of irrigation has it share of criticism and environmental concerns. In many European wine regions the practice is banned under the belief that irrigation can be detrimental to quality wine production. However, in the early 21st century some European countries have relaxed their irrigation laws or reevaluated the issue. Of the criticisms leveled towards irrigation, the most common is that it disrupts the natural expression of terroirTerroir
Terroir comes from the word terre "land". It was originally a French term in wine, coffee and tea used to denote the special characteristics that the geography, geology and climate of a certain place bestowed upon particular varieties...
in the land as well as the unique characteristics that comes with vintage
Vintage
Vintage, in wine-making, is the process of picking grapes and creating the finished product . A vintage wine is one made from grapes that were all, or primarily, grown and harvested in a single specified year. In certain wines, it can denote quality, as in Port wine, where Port houses make and...
variation. In regions that do not practice irrigation, the quality and styles of wines can be dramatically different from vintage to vintage depending on weather conditions and rainfall. Irrigation's contribution to the broader globalization of wine
Globalization of wine
"Globalization is the expansion of brands across nations and into other continents. In food and wine it refers to the whole problem of making the product global. The primary issue is scaling production while reducing the costs of goods with processes. In marketing it refers to wearing the mantle of...
is criticized as promoting a homogenization or "standardization" of wine.
Other criticisms center around the broader environmental impact of irrigation on both the ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
around the vineyard as well as the added strain on global water resources
Water resources
Water resources are sources of water that are useful or potentially useful. Uses of water include agricultural, industrial, household, recreational and environmental activities. Virtually all of these human uses require fresh water....
. While advances in drip irrigation has reduced the amount of waste water produced by irrigation, the irrigation of substantial tracts of land in areas like the San Joaquin Valley
San Joaquin Valley
The San Joaquin Valley is the area of the Central Valley of California that lies south of the Sacramento – San Joaquin River Delta in Stockton...
in California and the Murray-Darling Basin
Murray-Darling Basin
The Murray-Darling basin is a large geographical area in the interior of southeastern Australia, whose name is derived from its two major rivers, the Murray River and the Darling River. It drains one-seventh of the Australian land mass, and is currently by far the most significant agricultural...
of Australia requires massive amounts of water from dwindling supplies. In Australia, the centuries old practice of flood irrigation used in places like the Murrumbidgee Irrigation Area
Murrumbidgee Irrigation Area
The Murrumbidgee Irrigation Area is geographically located within the Riverina area of New South Wales was created to control and divert the flow of local river and creek systems for the purpose of food production...
caused severe environmental damages from water-logging, increase salination and raising the water table
Water table
The water table is the level at which the submarine pressure is far from atmospheric pressure. It may be conveniently visualized as the 'surface' of the subsurface materials that are saturated with groundwater in a given vicinity. However, saturated conditions may extend above the water table as...
s. In 2000, the Australian government invested over A$3.6 million into research on how to minimize the damage caused by extensive irrigation. In 2007, concerns about ecological damage to the Russian River
Russian River (California)
The Russian River, a southward-flowing river, drains of Sonoma and Mendocino counties in Northern California. With an annual average discharge of approximately , it is the second largest river flowing through the nine county Greater San Francisco Bay Area with a mainstem 110 miles ...
caused government officials in California to take similar measures to cut back water supplies and promote more efficient irrigation practices.
Other uses for irrigation systems
In addition to providing water for plant growth and development, irrigation systems can also be used for alternative purposes. One of the most common is the dual application of fertilizerFertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
with water in a process known as fertigation
Fertigation
Fertigation is the application of fertilizers, soil amendments, or other water-soluble products through an irrigation system.Chemigation, a related and sometimes interchangeable term, is the application of chemicals through an irrigation system...
. Commonly used in drip irrigation systems, this method allows similarly regulate control over how precisely how much fertilizer and nutrients that each vine receives. Another alternative use for sprinkler irrigation systems can occur during the threat of winter or spring time frost. When temperature drop below 32 °F (0 °C), the vine is at risk of developing frost damage that could not only ruining the upcoming years harvest but also kill the vine. One preventive measure against frost damage is to use the sprinkler irrigation system to coat the vines with a protective layer of water that freezes into ice. This layer of ice serves as insulation keeping the internal temperature of the vine from dropping below the freezing mark.
External links
- M. Veseth "Turning Water into Wine" American Association of Wine Economists, December 10, 2008
- E. McMullin "How irrigation management affects wine quality" Wines and Vines, June 1994
- M. Greenspan "Irrigation is Not Important" Wine Business Monthly May 15, 2009