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W i n e s & V i n e s D e C e M b e r 2 0 1 4 45 best of PraCtiCal winery & vineyarD Vineyard Irrigation Management: Good, Bad and Deficit by Yun Zhang, July 2014 Author Yun Zhang of Washington State University wrote the best-read Practical Winery & Vineyard story of 2014, accord- ing to metrics from our digital edition. In it, Zhang examines whether it's better to measure the amount of water lost to plants and evaporation (easy to track but not very specific), the amount of water needed to bring soil to a target level (practical, but requires frequent monitoring) or how much the vine itself requires to ripen fruit (the most precise method, though it re- quires expensive technology). Zhang describes how deficit irriga- tion techniques such as regulated deficit irrigation and partial root-zone drying can be used to control vigor and in- crease berry quality while maximizing water-use efficiency. Ultimately she ad- vises growers to use the data they've collected to design an irrigation strategy for quality, production and savings. Learn more about Zhang's research in the July 2014 issue of Wines & Vines. P R A C T I C A L W I N E R Y & V I N E YA R D J U LY 2 0 1 4 57 G R A P E G R O W I N G I n arid and semi-arid grapegrowing regions, irrigated viticulture is neces- sary to support consistent vineyard production. Moreover, well-managed irrigation is an essential part of vineyard practices and can potentially enhance quality. 5 Through controlling the amount of water supplied to grapevines, growers have the ability to control shoot growth and canopy size/density (which affect light exposure and air circulation in the fruiting zone), manipulate berry size and modify wine style in the vineyard. 18 However, ill-managed irrigation not only will not enhance grape quality, it could also be detrimental to the current growing season and even the following year's production. It is essential to understand how to manage vineyard irrigation. Moreover, under the global backdrop of increasing water shortages (due to climate change and/or urban development), producing better crops with less water is becoming especially important. Deficit irrigation in viticulture, when applied properly, can improve berry quality and also increase vineyard water use efficiency (WUE). 11 Fundamentals of irrigation scheduling Two fundamental questions related to irrigation scheduling are when and how much to irrigate. Approaches that can be used to aid irrigation decisions can be based on weather conditions, soil water status or vine water status. Evapotranspiration (ET) is the combi- nation of soil evaporation and plant tran- spiration. Reference ET (ET 0 ) is the ET from a hypothetical reference crop surface (i.e., grass) without any water stress. 1 The ET 0 can either be measured using a lysim- eter, estimated from pan evaporation or calculated using the Penman-Monteith equation based on meteorological data (humidity, solar radiation, temperature and wind speed). 1 As a standardized refer- ence, ET 0 from different locations or vari- ous years can be compared, and it offers accurate and real-time information of the changing weather. In order to adapt ET 0 to a specific crop (wine grapes), a crop coefficient (K c ) is multiplied with ET 0 to calculate crop-spe- cific evapotranspiration (ET c ) (ET c = ET 0 × K c ). 1 It has been reported that K c is cor- related with grapevine canopy features such as leaf area and canopy cover, 15 or growing degree days (GDD). 4 Moreover, K c is affected by climate, grape variety and layout of a particular vineyard. 12,15 Water stress would also alter the values of K c . 13 Therefore, local calibra- tion of K c is necessary, and the tracking of vine growth (or soil and/or vine water status) can improve the calibration. 12,16 For example, the changes in soil mois- ture in Figure 2 appeared as season-long water stress was imposed. However, it was not intended and irrigation was applied at 100% ET c (K c was calculated based on current season growing degree days. It demonstrates the importance of monitoring soil/vine water status other than simply applying irrigation based on a certain fraction of ET c . Soil water status can be measured as either soil water content (using neutron probe or time domain reflectometry, often expressed as percentage of soil vol- ume, v ) or soil water potential (using tensiometers or psychrometers, soil ). Using the soil water retention curve, v can be converted to soil , or vice versa. The advantage of measuring soil water status is that it directly indicates the amount of irrigation required to fill the soil profile to a target level. However, the soil water content or potential may not reflect the vine water status, which directly affects vine physiological pro- cesses. 19,20 Different types of soil have various water-holding capacity. There- fore, knowledge of the soil types in spe- cific vineyard blocks is essential for correctly interpreting the measurements of soil water status. Vine water status: A grapevine is the "middleman" between soil and atmo- sphere; its water status is affected by both soil water supply and atmospheric demand for transpiration. Therefore, measuring vine water status is the most direct way to assess the water stress level in a vine. Many parameters can be used to "sense" vine water status, such as simple visual indicators of vine growth, mea- surements of vine water potential ( vine ) and vine physiological responses to water availability (such as shoot growth rate, leaf gas exchange, sap flow rate and canopy temperature). • Visual indicators of grapevines: Observing and keeping a record of visual indicators of grapevines (the growth of shoot tips/tendrils and leaf orientation, see Figure 1) is the easiest way to know whether water is available to support active growth or not. For example: • Turgid and actively growing shoot tips/ tendrils indicate adequate water supply, while flaccid and wilting shoot tips/ tendrils are the first sign of water stress. • When water stress continues, shoot tips/tendrils will desiccate and fall off. • Leaves will orient away from direct sunshine under moderate water stress. • Any lateral shoot growth indicates no water stress. Observing visual symptoms serves well as a quick routine check-up. How- Yun Zhang, Washington State University BY Good, Bad and Deficit VINEYARD IRRIGATION MANAGEMENT Figure 1. Visual indicators of vine growth can be easily observed to assess water stress. Left: Water stress causes absence of tendrils and shoot tip, and changed leaf orientation on a grapevine shoot. Right: Actively growing tendrils and shoot tip are evident on a shoot without water stress. best of features The Winery of the Future by Paul Franson, April 2014 A presentation at the Wine Executive Program offered by the University of California, Davis, prompted Wines & Vines senior correspondent Paul Fran- son to take a closer look at "The Winery of the Future," as envisioned by profes- sors David E. Block and Roger Boulton. According to statistics from wines andvines.com, Franson's story was the best-read feature of 2014. As members of the UC Davis Depart- ment of Viticulture and Enology staff (Block is now department chair) during planning and construction of the new teaching and research winery, the pair have spent countless hours considering ways technology can improve wine- making and eliminate waste. Many of these practices are common- place in other areas of agriculture, while some were even incorporated into the facility in Davis (photovolactic cells used to generate to electricity and heat water, captured rainwater used for cleaning and irrigation). Other elements are innovative to the point they haven't yet been put into ac- tion. According to Boulton, CO 2 col- lected during tank fermentation could be sequestered and added to a solution to form calcium carbonate (otherwise known as chalk). He added, the seques- tration system will "demonstrate the storage of seasonal production for later, easy transport to others and the reuse of the calcium oxide itself." To learn more about Boulton and Block's vision for the future, check out the April 2014 issue of Wines & Vines. American Oak at the Source by Andrew Adams, February 2014 Wines & Vines' February 2014 cover story, "American Oak at the Source," was the best-read feature among sub- scribers to our digital edition this year. To write the article, associate editor Andrew Adams traveled to the oak for- ests of Missouri, where he met with log- gers, mill owners and coopers to get a sense of what sets domestic barrels apart and how the American oak indus- try has changed over the years. He found that American white oak can be quarter-sawn at the mill due to its large cellular structure. The result? More staves can be cut from a single American oak tree than a European oak, which must be split by hand or using powerful wedge presses. Ameri- can oak is also naturally watertight. While cooperage accounts for just 5% of the total market for American white oak—and most of that is destined for the spirits industry—at least one multi-generational logger told Adams that the wine industry helped keep his business afloat during the Great Reces- sion that started in 2008. Read "American Oak at the Source" on page 32 of our special report about barrels in the February 2014 issue. 52 W i n e s & V i n e s A P R i L 2 0 1 4 W i n e s & V i n e s A P R i L 2 0 1 4 53 soluble solids and acidity. Many wine- makers still don't have access to instru- ments that can analyze tannins and anthocyanins. Instead they taste the grapes to assess these components, but their findings depend on their own expe- riences and inherent tasting abilities. Fortunately, improvements in sensors combined with powerful computers—pos- sibly even smartphones—can help provide quick field tests for polyphenols, includ- ing the use of near-infrared spectroscopy to measure anthocyanins. Having more knowledge of juice com- position can help predict how it should be fermented, including timing of harvest and processing steps, nutrient additions needed (if any) and even how to best manage the cap for red wines. This pro- cess can now be based on data from research and past harvests applied to the current juice's composition. Likewise, comparison of the must in a stuck fermentation with previous solu- tions, or best extraction of desired proper- ties in red wine without excessive tannins, might be a matter of finding the optimum pattern in prior similar situations. Grape sorting and pressing Careful sorting of grapes has been widely adopted by high-end wineries to produce better wines, namely wines with intense flavors without undesired bitter tannins or green, overripe or moldy characteristics. This initially was done via cluster selec- tion, then with banks of workers remov- ing by hand defective berries, jacks, leaves and other material other than good grapes. Now automated systems are becoming cost-effective as well as poten- tially superior. Some are simply shaking grids that allow only berries to pass through, but the most sophisticated involve real-time image analysis and help create the winery of the future today. The machine is "trained" with photo- graphs of desired berries, and then as the berries move past a scanner the machine keeps those that match the images. Every- thing else is discarded. This equipment can process up to 10 tons per hour and leave only well-formed berries. Another process open to improvement through technology is pressing. At pres- ent, winemakers determine the length of time and pressure for pressing grapes mostly by experience, but online sensors could monitor the output of a press for phenolics and color density to control the pressure and separate wine into different fractions. Improved information One key to improving winemaking is to be able to access data and control pro- cesses. A laboratory information manage- ment system (LIMS) can store results of a range of instruments such as spectrom- eters, autotitrators or even high-perfor- mance liquid chromatography (HPLC) tests into a process database that can be accessed not only by winemakers and viticulturists but also others in purchasing and marketing. A process-management system could likewise automate and control operations under a winemaker's direction. A supply chain/production-management system could go further and include data from vineyards, blending, bottling and packaging, even distribution and retailing in one database. It could also provide information needed to regulatory agencies like the TTB and ABC. Implementing this level of automation can make some workers uncomfortable. One approach to overcoming that is to identify current automation needs and anticipate future automation needs as well as current management and operator comfort with automation. Based on that, a winemaker can design for current needs with the current com- fort level of automation (or just above it), yet install equipment capable of meeting future automation needs. The staff's com- fort level would rise as the winemaker increases automation with the existing equipment. Clearstories and solar tubes allow outside light to enter buildings without glare. They also screen infrared and ultraviolet rays. W hile a few winemakers have consciously adopted a Luddite-like anti-tech- nology position, most recognize that science and technology have led to better wines. Few places have done more to further the science of winemaking than the University of California, Davis, and its research and teaching winery and new sus- tainable research facilities (see "On Cam- pus, Off the Grid" in the July 2013 issue of Wines & Vines) are already perfecting many old processes as they test new ideas. The chair of the Department of Viticul- ture and Enology at UC Davis is David E. Block, a chemical engineering Ph.D. who is also a professor in the Department of Chemical Engineering and Materials Science there. Block formerly worked in another field utilizing fermentation, biopharmaceuticals. He, along with another chemical engi- neer and veteran V&E professor, Dr. Roger Boulton, have devoted much time to considering the winery of the future. Block presented their thoughts at the 2013 Wine Executive Program con- ducted by the UC Davis Graduate School of Management. The focus of the talk was incorporating new technology into winemaking, both in making wine and in improving manage- ment of utilities and waste. The emphasis was solving key issues facing the wine industry, increasing wine quality, reducing processing costs and increasing sustainability while better man- aging natural resources. New technology can help meet all of those goals. This arti- cle summarizes Block's comments. The technologies that improve the winemaking process—and also improve wines—arise from a number of sources including R&D with a specific goal and the application of fortuitous inventions developed for other purposes. The wine industry can apply techniques developed for other industries including dairy pro- cessing, beer making and pharmaceuticals. Fortunately, many changes can improve the wine while reducing cost; saving money doesn't necessarily compromise quality. Data helps decide harvest Some of the improved technology is in instrumentation, which can provide better information for the winemaker to use in making decisions. An example is deciding when to har- vest. Once upon a time winemakers set harvest dates by the lunar calendar or saints' days. In more recent times harvest was based on simple measurements of The Winery of the Future Elements of it are operating today, say UC Davis professors By Paul Franson Highlights • Technology and research-based knowledge can improve the quality of wine and reduce the cost of pro- duction and waste of resources. • Even those who reject winemaking technology like filters, micro-oxygen- ation and reverse osmosis can take advantage of instrumentation and monitoring. • Recycling and reducing the use of resources like water, energy and even heat, cold and carbon dioxide may eventually be required. Photovoltaic cells generate electricity from sunlight, and some wineries also heat water with the sun. Laboratory information management sys- tems software supports lab operations. Spectro photometer Viti culturist Wine maker Pur chasing Marketing Autotitrator PROCESS DATABASE HPLC G R A P E G R O W I N G G R A P E G R O W I N G W I N E M A K I N G W I N E M A K I N G EDITORIAL b e s t o f 2 0 1 4