Monthly Archives :

August 2018

Capturing Carbon on your Vineyard
Capturing Carbon on your Vineyard 659 353 Sectormentor

“If you want to capture carbon, you have to think like carbon!”

Check out this Short from Farmerama Radio, a podcast sharing the voices of smaller scale farmers, about Carbon Farm Plans and monitoring carbon from Charles Schembre at Napa County Resource Conservation District.

Charles Schembre is a Soil Conservationist at the Napa County Resource Conservation District, working primarily in Vineyard Agriculture. He received grant funding from California’s Healthy Soils Program to start the Carbon Farm Plan project, a scheme to support vintners with increasing soil health, sequestering carbon and improving water retention.

Sequestering or increasing soil organic carbon is the process of plants absorbing carbon dioxide from the atmosphere, and transforming it into carbon in the soil through photosynthesis. This is beneficial for reducing greenhouse gases, in addition to increasing soil fertility.

Charles is working with farms and vineyards to create holistic ‘Carbon Farm Plans’, which assist them to increase their agricultural resilience and productivity, and mitigate the impact of our rapidly changing climate with sustainable farm management practises.

In this short episode of Farmerama, he explains how ‘Carbon Farming’ works, what a carbon farm plan is and how you can monitor this on your farm:

You can see an example carbon farm plan from the USDA Napa County vineyard here.

Carbon sequestration is a win-win, right?
Yes, however, making a plan and monitoring it’s success is the challenge. The idea for the plan is to put all potential options in, and then chip away to find what’s realistic. In terms of soil health there are several different tactics he suggests you can use to increase carbon in your soil and monitor how they are working:

  • No-till: This is the practise of not ploughing, leaving soil undisturbed, protecting against soil erosion and allowing microbes, fungi and worms to do their great work building soil health. This is one of the easiest practises to implement as it doesn’t involve much financial commitment, so a lot of the farms using carbon farm plans try it first.
  • Compost: Adding compost to the soil builds up it’s soil organic matter content. The benefits of this practise are much longer term. Charles recommends adding large compost applications to soil perhaps every 5 or even 10 years.
  • Ground cover: The more ground is covered in plants, the better. If you want to capture carbon, you need leafy green plants, absorbing CO2 from the atmosphere and putting it into the ground. So those, ‘untidy areas’ of the farm, rife with riotous plants and weeds, might actually be doing your soil a favour. Think twice about getting rid of them next time!

Soil monitoring
To understand how much carbon sequestration you are achieving Charles advises you start monitoring these three soil health indicators (identified by Soil Health Institute):

  • Wet aggregate stability (Slake test): this is the soil’s ability to withstand disintegration from water erosion. You can do the slake test at home! (our soil health expert Jenni Dungait has put together a great simple protocol that she has used extensively in research with farmers)
  • Bulk Density: this is the unit of dry soil & air per unit of bulk volume. It changes depending on different land management practises. The test is best done in a lab, and involves drying a soil sample in an oven at 105 degrees for 18-24 hours.
  • Soil Organic Carbon: this is a part of soil organic matter which is traditionally measured with the Loss-on-ignition test (also best done in a lab). However recent research by Soil Health Expert Jenni Dungait has shown that the wet aggregate stability test (or slake test) above is a proxy for Soil Organic Carbon when following this protocol.

There has already been a proven reduction in greenhouse gases on several of the farms using carbon farm plans. Do you think you can make your own carbon farm plan? Check out Charles’ Carbon Farm Plan for their demo vineyard, Huichica Creek.

Contact us to find out how our app Sectormentor for Vines helps you record & learn how your soil is changing.

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The art and science of accurately predicting your vineyard yield
The art and science of accurately predicting your vineyard yield 1920 1440 Sectormentor

Why do crop estimates?

Crop estimates are important for many reasons for both grower and winemaker. Growers want to produce high quality fruit to get the best price for their grapes, or if it’s for their own wine, then to get the best quality wine. Ideally, the grower really wants to get the best quality grapes AND maximise their yield AND maintain the health of the vineyard. The crop load also affects harvest costs and logistics such as the timing of harvest, ensuring you have enough pickers etc. Of course crop load can also affect vine health.

As one researcher writes, “Overcropping a vine has many well documented negative impacts on fruit and vine quality including reduced and delayed fruit ripening, potential vine stress that may lead to increased susceptibility to winter injury, disease problems especially late season rots and other significant problems. Undercropping can also affect wine quality, as well as cheat you of valuable revenue.”

Vintner Will Davenport also pointed out “Knowing your (accurate) crop estimate can help to understand if fruit thinning is necessary and how much of the crop needs to be removed in order to keep the vine healthy and ripen the remaining grapes.”

Winemakers are also interested in crop estimates as they need to juggle tank space, and want to know which grapes are coming in when. Plus they need to know how many grapes they will be buying, and what they will then produce and have to sell.

 

Getting your initial crop estimate

Early in the season, often around flowering, you establish the number of clusters by going out and counting the number of flowers (we are referring to the whole inflorescence as a flower here) in each different block, or plot, of similar vines. This is a quick and easy way to give you an estimate of the number of bunches of grapes you will have, and therefore a general estimate of your yield.

There are a few things that can affect the accuracy of this part of the prediction significantly. If there is a frost, or a heavy rain/hail incident before fruit set and many flowers are lost, or if just before picking badgers come and eat all your fruit. But for the most part the majority of flowers will turn into bunches and bunch number is pretty predictable.

Using the Sectormentor for Vines app it’s very easy to collect flower counts on your phone and then the app automatically averages those counts for you, per block or variety. Our yield predictor tool is setup to assume 100% fruit set initially, but if there is some incident that changes this, it’s easy to go back and reduce the % fruit set for each block or variety.

 

 

Finding average bunch weights for your vineyard

The variable that is much less easy to anticipate in yield prediction is bunch weight. This varies every year depending on weather and the many other facets of the natural world that keep us on our toes. It is also often different for each variety or clone. It is only once you monitor bunch weights for each plot for a number of years that you start to have a pretty good idea of the average bunch weight for your vineyard, or at the very least the maximum and minimum average weights.

If you aren’t already monitoring this, then we definitely recommend recording average bunch weight for each block starting this harvest, this information is invaluable in the long term, we would consider it an asset to the vineyard! Of course this is very easily recorded and accessed with the app.

 

THE TRICK! How to get a more accurate crop prediction

To get an accurate yield prediction is part art, and part science. Knowing your average bunch weight stands you in good stead, but we have spoken to quite a few vineyards and all those that consistently get within 5% accuracy on their yield prediction use the beautifully simple art of going out and actually looking to judge (guestimate) what the average bunch weight will be this year, and then use that to adapt their yield prediction. This happens around the time of veraison, when vineyard managers will return to each plot in the vineyard and look at sample vines, visually estimating the eventual bunch weight for each bunch on the vine. This is the ‘art’ part and definitely gets easier the more experience you have.

 

 

How do other vineyards do it?

We have heard some clever ways of doing this:

Once at least 50% of the grapes have gone through veraison, Nigel Riddle at Wodetone Vineyard in Dorset picks a large bunch of grapes for each block and weighs it so that it’s 100g (take off extra grapes if it’s too heavy). He then goes to a series of sample vines and holds the 100g bunch in front of the bunches on the vine. By visually comparing with the 100g bunch in his hand, he can estimate the average weight of the bunches on the vine. After doing this for a while he doesn’t even need to carry around the 100g bunch with him as he can reasonably estimate the weight of each bunch just by eye. We chatted with Nigel and he agreed that to get started it might be best to compare the 100g bunch to each individual bunch on every vine at your sample site and record visually estimated weights on a bunch by bunch basis. But as you get better you can begin to record an estimated average bunch weight on a vine by vine basis.

At Davenport Vineyards the team have been working with the same vines for many years and they use a combination of historical data and visual surveying to optimise their prediction. They go out to their sample sites just as veraison begins and count the number of bunches on each vine. This gives them an accurate % flower set number which is helpful in future years, it also verifies the actual number of bunches on each vine. At this point they also do an estimate of the average bunch weight on each vine. The Davenport team do this purely by eye, they know what the maximum and minimum average bunch weight was for that variety and block in previous years. They use this range of numbers and their experience from past years to judge if the grapes on each vine are larger/smaller compared to previous years, and then estimate an average bunch weight for each vine at the sample site based on this. Will recommends making a best-case and worst-case scenario yield prediction for each variety based on the range of bunch weights you would expect for that variety. Luckily, this is easy to do using our yield predictor!

Another US-based vineyard told us how they use the lag weight method. Lag phase is a period of little or no growth in berries between two periods of rapid growth, it’s the point where the plant puts its energy into hardening the seeds and starts really building sugars shortly after. It happens just around veraison, and approximately 50-60 days after bloom. (See the graph below for a nice visual representation of lag phase). The vineyard manager will actually weigh the clusters on the sample vines at lag phase. It is estimated that grapes increase in size by 50% from lag phase to harvest, and therefore they multiply the lag cluster weight by approx 2 to estimate the final cluster weight and yield. Then in the weeks before harvest they will go out and look again and based on previous years experience they might increase or decrease the cluster weight multiplier (e.g 1.8 rather than 2).

Of course a vital part of this method is getting the multiplier correct for each block/variety based on how big the clusters look on the vine that year. It was also interesting to hear that Nigel at Wodetone doesn’t use a multiplier in his estimates when he weighs the 100g cluster a number of weeks before harvest, however he consistently gets good estimates. Nigel pointed out that most sparkling wine is harvested at 18 Brix, rather than 22 Brix, so we would expect a much lower weight increase between veraison and harvest for sparkling wines. We reckon it’s a combination of slightly smaller grapes at harvest for sparkling wine in the UK, and the fact that we humans are ever-optimistic in our estimations, which means that his method works perfectly without taking into account any increase in weight of individual bunches.

Credit: https://ohioline.osu.edu/factsheet/HYG-1434-11

Do the same thing each year

A key to getting a good consistent yield prediction is to use the same method each year. It is also important to not be disheartened when you are starting out, as predictions may be up to 20% out, this is ok initially! As you get more experience and build up your numerical vineyard history it will all become more accurate and easier.  If you are consistently getting it way out after a couple of years, then you probably need to sample more vines…or rethink your methodology.

Using Sectormentor for Vines for your yield prediction

We have built Sectormentor for Vines to work with both the art and science of vineyard monitoring. The app makes it very easy to collect bunch counts and bunch weights out in the vineyard and then the yield predictor makes it easy to turn that information into a yield prediction for each block or area of vines you want (see diagram below). The tool is also flexible so that you can consider minimum and maximum predictions. Of course this is just one of the many tools the app provides, including a Ripeness Monitor, Soil Health Indicator and more. Please get in touch with any questions or if you’d like to hear more about how the app might work for you.

UPDATE: We’ve recently upgraded our Yield Predictor Tool so that you can optimise your predictions with flower / bunch counts, and bunch weights! Learn all about the updated features in Part 1 & Part 2 of our more recent blogs about this!

 

How do you do your yield prediction? Do you have another method you think works well?

We are always learning what works and how people do crop estimates on their vineyard so please do email us if you have anything to add or any questions.

Resources:

Thank you to Nigel Riddle at Wodetone Vineyard, Will Davenport and Phil Harris at Davenport Vineyards and the following resources for help putting this article together.

https://ohioline.osu.edu/factsheet/HYG-1434-11

http://pawinegrape.com/uploads/PDF%20files/Documents/Articles/Crop%20Estimation.pdf

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How to prepare for data collecting in your vineyard
How to prepare for data collecting in your vineyard 1920 1440 Sectormentor

Monitoring and analysing your vines helps to predict grape yield and when to harvest your grapes to get the highest quality.

How many vines should I monitor?

First you need to create a sampling plan which is clear and easy to manage – making sure it’s actually doable is the most important element. If it’s too complicated you are likely to lose patience with it! Research recommend you sample 3% of your vineyard – this is the minimum suggested to get a representative sample for predicting your grape yield. In our experience many commercial grape growers sample closer to 1-2% of the vineyard and can still get very good predictions — the key is to make sure you are regularly going out and looking and adjusting any predictions based on what you see. It is after all an art and a science!

Bride Valley Vineyard

Which vines should I monitor?

We recommend ‘proportional stratified sampling’, which in basic terms means splitting your vineyard into smaller somewhat homogeneous blocks. Maybe your vineyard is already naturally broken down, for example you may plant different varieties or clones in blocks in the vineyard, that makes it simple! If you have a large-ish area of vines that significantly under or over performs in comparison to other area you could also define this area as its own block.

If you don’t have anything like this in place already, don’t worry! Think about your number of rows and the number of bays on each row, and draw a simple map of the vineyard, then outline the different blocks of vines that are similar. When using Sectormentor it’s also good to think about what you need this information for? For example, often (especially initially) vintners manage all clones of a specific variety in the same way. However, they will still setup Sectormentor to monitor based on blocks of clones, that is because they need to do separate yield predictions for each clone for the winery and therefore to get that level of information they need to ensure they are sampling enough vines within each clone.

The key questions to ask yourself when determining what will be your ‘block’ of vines are: when harvesting, what do you (or your winemakers) want to know the yield for, each variety? Each clone?  Each clone-rootstock combo? And when doing a specific activity, or yield prediction, do you want to make decisions based on variety? Or clone? or….?

Oxney Organic Estate Vineyard

How do I choose sample sites?

Once you have your blocks defined, you can decide which vines to sample within each block. It is suggested you sample 1-3% of vines in each block using a systematic method of selecting random samples (systematic sampling). You should always start a few rows in to avoid getting skewed results from the rows on the edge of the vineyard.

When you use Sectormentor to record counts a sample sites you have a few options:

  1. You can use scan a contactless (RFID) tag, which immediately identifies the sample site you are working in. Contactless tags make it simple, because you can attach them directly to the vine supports, and then scan them when you want to collect data at their location. Each sample site can have it’s own contactless tag.
  2. You can also use the GPS function on the Sectormentor app to set the location of your sample sites, so you can view them all on a map and find them easily out on the field. (Many people use this alongside the contactless tags)
  3. Some vintners choose to sample randomly and go to a set number of vines, but at ‘random’ locations each time. On the largest vineyards this is sometimes more convenient, but it’s often not the most accurate method because we humans aren’t very good at choosing random locations on the fly. It is also possible to setup Sectormentor this way if you’d prefer – if you are interested let us know and we can set this up for you.

RFID tag at Bride Valley Vineyard

What is an example of systematic sampling?

Let’s look at an example setup. Let’s say you have a vineyard split into 2 blocks, based on 2 different clones planted. Each of these blocks is relatively homogeneous. Consider one block, if a block has 30 rows with 20 bays in each row, and each bay has 5 vines. This means there are 100 vines/row. So that is 3000 vines in that block (see diagram below). You plan to sample close to 3% of the vines, then you have to sample 90 vines.

Using systematic sampling, you could pick every 5th row to sample, excluding edges. And if each row has 20 bays, you could have a system across the vineyard of always sampling from the 3rd, 9th and 15th bays. These bays are where you put the RFID tag and start the sampling from.

For efficiency we suggest sampling multiple bays at each location, so in this example you would always sample 3 bays from the tag, so if the tag was at bay 3, then you would use that tag to sample bays 3, 4 and 5.

Alternatively you could do systematic sampling across the entire vineyard for example every 4th vine on every 6th row. So you go to every 6th row and sample vines 4, 8, 12, 16, 18, 22 etc along that row. Although this method could potentially be more comprehensive, it can take longer to complete, and may not be manageable for your vineyard. For this method, we recommend putting one RFID tag at the end of the row, so you have sample rows instead of bays. When you scan the RFID tag the Sectormentor app will automatically remember which row you are on and save the data for all vines along that row.

One North Eastern US study states: “Crop estimation helps ensure consistent production of high-quality fruit over multiple years in our variable climate. A grape grower who is unable to invest in, or elects to ignore, developing operational competence in crop estimation is likely to be at a competitive disadvantage in tightening markets.”

Interested in understanding more about your vines?

Check out our Sectormentor app which makes data collection in the field simple and easy, as well as analysing trends turning that data into helpful insights at home on your computer. If you have any questions don’t hesitate to get in touch with us: info@vidacycle.com

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