930 Shiloh Road, Bldg. 44, Suite E, Windsor, CA, United States of America, 95492

http://www.advancedvit.com

(707) 838-3805

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What It’s Like to Have Real Time Plant Stress

I once saw a commercial that said: “forget everything you thought you knew about slip covers”.

So I did.

Admittedly I don’t know a lot about slip covers. I do know quite a bit about plant stress. Up until recently, our constant flow of data on soil moisture has been studied along with weekly spot measurements of leaf water potential via pressure bomb. This year we switched to FloraPulse® plant stress sensors and holy moly, having real time data on plant stress is pretty wild.

First of all, how much data are we talking about?

This graph compares our real time plant stress measurements with what would be weekly midday pressure bomb measurements. Look at how much data we were missing just by looking at only weekly snapshots of plant stress. There is a lot of stuff going on those other 6 days, not to mention at night.

Pressure bomb measurements are hypothetical. Stars are placed where weekly measurements would be made to illustrate data missed by manual measurements. SWP measured in Bars. The lower the number, the higher the stress.  

Some vines recover at night. Others don’t.

For my pressure bombers out there, you may remember that there have historically been two important times to sample leaf water potential: midday and pre-dawn. This means if you are a passionate whipper snapper slogging it out in a graduate program, you don’t just have to sample at the hottest time of day. You get to sample at 3 am too!

Why? Well aside from weeding out those who are more suited for the cellar kind of life, these sampling times give you different information. Midday gives you the most stress (most negative leaf water potential) the vine will experience that day. At night, the stomata close i.e. photosynthesis and transpiration pauses, and the vine goes into relative equilibrium with the soil. This is when the vine recovers as much as it can depending on how moist the soil is.

Realtime data is giving us a more complete picture. Some vines swing wide between having close to 0 stress (water potential) at night and being very stressed during the day. That time of maximum stress (most negative water potential) is later in the day than we originally thought – usually around 5pm local time. Others have a much tighter amplitude, getting moderately stressed during the day but recovering very little at night. For the most part, the degree to which vines recover tracks with soil moisture levels. There seems to be more nuance though and that could depend on rootstock, soil texture, or a combination of both.

Note that the FloraPulse® sensor measures trunk or stem water potential, which will differ from leaf water potential, which is what we usually measure with the pressure chamber.

The following graph is from a site where the vine recovers fully every night (SWP>-2 Bar) even though midday SWP continues to decrease (become more negative) over the course of the season.

This graph (below) showcases a site where vines don’t recover fully at night. 

Recovery after irrigation varies

For the most part, vines recover rapidly when the vines get irrigated. The degree to which they remain in that recovered state depends. Again, this could be related to soil texture or rootstock or even variety. We have always considered the point at which root uptake starts to level off as indicative of the vine having a hard time finding water to extract. Plant stress does seem to track with that. We were right. Cool.

The following graph illustrates how irrigations can offer temporarily relief from water stress. After each irrigation, the vine gets gradually more stressed. 

The below graph showcases a site where irrigations only offer brief relief from stress. Within 1-2 days, vines are as stressed as they were prior to each irrigation.  

Read the full article here.

Plant Stress

About

Full-Service Vineyard Company with a Committment to True Sustainablility
 
Advanced Viticulture, Inc. is a full-service vineyard management and winegrowing consulting company that operates from a standpoint of sustainability. From a philosophy of minimal inputs to the vineyard, we achieve environmental protection while allowing each sites uniqueness to be expressed in their wines. Reduction of pesticide, fertilizer and irrigation inputs allows the vineyard's characteristics to shine through to the wines.
 
Our management company is full-service. From site preparation to vineyard establishment and vineyard management, we have an attention to detail that results in first-rate vineyards.
 
Our consulting and technology company is full-service. We can be engaged for a brief diagnostic visit, a defined project or an ongoing advisory arrangement. Vineyard moisture, mineral nutrition and pest/disease monitoring programs are offered. Moisture monitoring, weather stations and automation technologies are offered through our company and we provide full support and are backed by our manufacturing partners. Projects and pricing structures can be tailored to match your goals and your budget.

Advanced Viticulture's principal viticulturist is Mark Greenspan, Ph.D.
 
Mark has over two decades of viticultural experience. His background includes a Masters degree in Horticulture/Viticulture and a Doctorate in Agricultural Engineering, both from the University of California, Davis. He is one of very few private practitioners who have been elected as an honorary member of Gamma Sigma Delta, the Agricultural Honor Society.
 
He is regarded as one of the worlds leading experts in winegrape irrigation and has written scientific and trade journal articles on the subject. In addition to his command of grapevine irrigation practices, he has extensive experience in vineyard mineral nutrition, crop load management, vineyard uniformity, grape maturation, weather, climate and viticultural technologies. Mark holds certifications from the American Society of Agronomy as Certified Professional Agronomist (CPAg) and Certified Crop Advisor (CCA). He is also a licensed pest control advisor (PCA) in California (#131135).
 
With a background in electronics engineering, coupled with mastery in viticulture, Mark is uniquely equipped to support the implementation of technology in the vineyard and does so through numerous corporate partnerships.
 
He has frequently delivered presentations on numerous topics to his colleagues in the wine industry at venues ranging from small classrooms and vineyard tailgate meetings to large industry-wide symposia.
 
Mark is a regular contributor to wine industry publications, including Practical Winery and Vineyard andWine Business Monthly. He has been contributing a monthly column on viticulture for Wine Business Monthly since 2005.

Contact

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Title Name Email Phone Extension
Dr. Mark Greenspan mark@advancedvit.com 707-838-3805

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Advanced Viticulture, Inc. 930 Shiloh Road, Bldg. 44, Suite E, Windsor CA United States of America 95492

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