Symposium Reveals Novel Uses for Precision Viticulture

By: Annie Klodd, University of Minnesota Extension 

What role do you see precision agriculture playing in the world of viticulture, and how do we get over the growing pains to make it a reality? These were the key questions addressed during a recent Precision Viticulture Symposium co-hosted by the American Society of Enology and Viticulture and the National Grape Research Alliance

 

For many grape growers, precision agriculture may be a totally new concept, while others have been using it, knowingly or unknowingly, for a while. It is an ever-growing field of technology where growers map data across their fields to manage crops more profitably and efficiently. Think soil moisture, plant vigor, pests, and soil nutrient content. 

  According to Rob Bramley, symposium speaker and a Senior Scientist at CSIRO in Australia, precision agriculture is built on the principle that land is variable. If a variable landscape is all managed the same, some areas will be profitable and others will operate at a loss.  

  So instead of managing an entire vineyard the same way, what if a grape grower could cater their management to the needs of each part of the vineyard? This is called “precision viticulture (PV).”  

  For example, a trained grower or advisor can create a vineyard map showing spatial variation in vine health, identifying low-performing areas that need extra attention and cutting costs on areas that need less help. 

  Simple maps can be created by plotting data that the grower collects on the ground, like from soil samples. In more advanced applications, maps incorporate data collected by satellites, drones, or sensors mounted to tractors and harvesters. 

  Research on PV has come a long way since the first juice grape yield maps of the 1990s. Still, it has a long way to go. Grape growers are just now starting to adopt precision agriculture, which is already widely used in row crops like corn and soy.    The symposium speakers expressed that as the research advances, PV should become increasingly accessible to the average grape grower. To dig into how this might look, let’s start with some of the most promising applications of PV: 

How is Precision Viticulture Being Used Today? 

  Today, researchers, consultants and farmers use app-based mapping software to create maps of important crop traits like soil qualities, yield, pest pressure, and plant health. Here are seven emerging or “future” applications that the symposium speakers highlighted for vineyards specifically: 

  Vine Vigor: Mapping vine vigor is one of the more basic uses of PV but does require access to drone or satellite imagery. Several companies offer drone and satellite imagery services for the ag sector.  

  Growers can use vine vigor maps to identify problem areas and improve canopy management.  

  Variable Rate Fertilizer & Pesticides: I have yet to meet a grape grower who thoroughly enjoys spraying. Growers could use nutrient and pest maps to apply only what is needed, and to vary what is applied across the vineyard based on need. This could be achieved by mapping vine vigor, soil qualities, foliar nutrient concentrations, and weed populations, among other things.  

  Mapping soil and foliar nutrient data is one application I would recommend for growers who want to dip their toes into PV – it is relatively easy to collect that data, and many of us do already. I talk later about app-based platforms you can use to plot data. 

  Early Pest Detection: Dr. Katie Gold, Assistant Professor of Grape Pathology at Cornell University, is using hyperspectral imaging to detect locations of key pests early so growers can target them more efficiently and effectively. 

  Dr. Gold leads a study that uses NASA’s AVIRIS satellite imagery to detect early signs of grapevine leafroll virus in California vineyards. She hopes this technology becomes accessible to growers and aims to expand it to other grape diseases like powdery mildew. 

  Precision Irrigation: Vinay Pagay and Bruno Tisseyre both discussed exciting research on precision irrigation. That is, mapping vine water status across the vineyard to apply irrigation by zones rather than applying the same amount of water everywhere. Pagay’s group is researching the use of crop water status index and drone-mounted NDVI sensors for this purpose. 

  Estimating Yield: Mason Earles and Jaco Fourie both spoke about ongoing research on image-based yield estimation. They are deploying sensors through the vineyard to capture images of clusters, to estimate fruit density throughout the vineyard and create yield estimation maps.  

  If the researchers are able to train the sensors to accurately recognize clusters and cluster size, this could enable more efficient yield estimation for larger vineyards where yield estimation by human crews is too time consuming. 

  Split Picking: Bramley described one intriguing use of PV, for “split picking.” That is, pricing fruit based on quality in particular areas of the vineyard. By mapping differences in fruit quality, anthocyanins, malic acid, and YAN across the vineyard, growers could identify their highest quality blocks and sell that fruit at premium prices. This is not currently a common practice. 

  Bramley argued that California wineries grade the fruit once it comes in, making split picking less relevant. However, I would also argue that it has potential in many wine-growing regions of the US where grading practices are not standardized. I could see it playing a role in Minnesota, where I am based. 

  UV light for disease control: Dr. David Gadoury, plant pathologist at Cornell University, has worked extensively to develop a method to control pathogens with UV light exposure during the night. Thanks to ongoing research efforts, this practice has come a long way over the last 30 years or so.  

  Currently, Gadoury’s team is finding excellent suppression of powdery mildew and mites using nighttime UV exposure. They have also had good suppression of sour rot based on one year of data. Their data also suggests that UV treatment can suppress downy mildew in a mild year but not a severe year.  

  They have found no evidence of harmful effects of nighttime UV application on the vine, and have found that it is effective across multiple specialty crops. Read more about this project here. 

  My personal take-home message was that UV technology is very promising, and equipment manufacturers will need to get on board in order for it to be widely adopted. 

Where are we on Adopting Precision Viticulture? 

  Are you feeling intrigued but don’t know where to begin? You’re not alone. Not too many grape growers have embraced PV yet. 

  But many feel that this is just the beginning of PV adoption, and some of the speakers cited strong interest in their regions. They feel that the potential for these tools is strong, because of their ability to improve vine management.  

  Most of the applications described above are not yet fully available, as researchers work to develop them. However, some applications such as yield maps, soil fertility maps, and vine vigor maps are entirely possible for growers willing to give them a try.  

  One major obstacle is finding the expertise and technical support to make it happen, and learning how to map data on your vineyard. Fortunately, Researchers are also working hard to develop tools that will allow growers to more readily use it. 

  Terry Bates from the Cornell Lake Erie Research and Extension Lab suggested that PV developers work on creating free, user-friendly web-based platforms that growers can use to get started. He and other speakers argued that working with PV-trained vineyard advisors would make this easier as well.  

  Bates works on the Efficient Viticulture Project and the myEV Platform (my.efficientvineyard.com), where growers can create accounts and collect, organize, map and interpret their own vineyard data. The goal is to make it easy and accessible. 

  According to Bates, many growers shy away from PV because of the learning curve. Bramley argues that avoiding PV due to the learning curve would be a “missed opportunity” for America’s grape industry.   

  I will add that some PV applications are much simpler than others, and growers can start small while learning the ropes. 

  Bates also recommends growers have a goal in mind for what they want to use PV for, rather than just generating (or paying for) cool vineyard imagery and then wondering how to use it.  

  For instance, if a grower is struggling with soil fertility, they could make it a goal to use PV to refine their nutrient management practices. They could do this by mapping soil and foliar nutrient data and vine vigor across the vineyard, and then altering their fertilizer regimen based on the needs of each zone. As emerging technologies become more accessible, such as the aerial-based nitrogen mapping described by speaker Alireza Pourreza, growers could combine that with their ground-level data to improve their level of information. 

  Ideally, they could find a consultant trained in precision agriculture to help them get rolling. 

  One of the biggest takeaways I got from the symposium was that trained viticulture consultants and perhaps even some Extension professionals will likely play a big role in helping growers implement PV in the future.  

  According to Bruno Tisseyre of L’institut Agro in France, trained advisors are key because they can become experts in the technology. They could provide the equipment and interpret the PV data it generates, allowing growers to focus on all of the other aspects of vineyard management. 

  The Precision Viticulture Symposium was co-hosted by the American Society of Enology and Viticulture and the National Grape Research Alliance. Funding was provided by USDA’s National Institute of Food and Agriculture, and sponsored by Turrentine Brokerage. The full speaker lineup can be found at https://graperesearch.org/asev-ngra-precision-viticulture-symposium/ 

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