By Jonathan Sercu

How fruit growers can benefit from using dendrometers on the job

How fruit growers can benefit from using dendrometers on the job

Crodeon is glad to announce that the Reporter is now compatible with the dendrometer sensor line-up of Ecomatik (DE). This enables many new possibilities for monitoring the growth and watering status of fruits and trees. In this post we will dive a bit deeper into some of the concrete advantages that growers will experience when making use of dendrometers on the job.

Monitoring growth progress

By installing a dendrometer as a grower you can keep track of the growth of the trunk over the years. In graph (A) below you can see a stem growth curve from almost three growing seasons increasing from 2000 µm to over 7000 µm. We can identify stem diameter growth, the annual growth rate increment and freezing periods with strong stem shrinkage. These are all important parameters helping you to track healthiness and vigour of your plants.

stem growth curve measured by dendrometer

When zooming in on the growth of one month in graph (B), we can see how the trunk behaves on a daily basis. We can clearly identify the day / night cycle and how these are affected by dry periods and rainfalls. The amplitude between daily shrinking and nightly swelling of the stem corresponds to the extend of which the plant has to consume its internal water storage pools to buffer high daily transpiration demand and its ability to replenish these reserves during the night.

Making sure your fruit grows tasty

When we measure the diameter of the trunk in combination with soil moisture, some interesting effects can be noted. The graph below shows the diurnal (daily) behaviour of the trunk over a period of one month. We identify four different conditions of soil water availability during this month indicated in green (well watered, luxury), yellow (mild water shortage), red (water shortage) and dark red (drought).

During the days marked in green, this tree got plenty of water, so it was able to supply daily transpiration almost completely from instantaneous water uptake and the diurnal amplitude is small. During the week marked in yellow, the tree was still able to take up enough water during night time to compensate for daily transpiration losses, except that transpiration was fed to a larger extend from the internal water resources (larger amplitude).

diameter amplitude in correlation to soil moisture

During the weeks marked in red and dark red, there was more transpiration during the day than water uptake at night. We clearly notice a shrinking trunk in the data. Unfortunately, this also results in a lower yield for this tree, even though the uptake and trunk diameter are restored back to healthy levels on October 7th.

Now here comes the best part. Whereas in the early expansion phase of fruit development we would like to remain in the green area and avoid limitations of rapid fruit growth, it is the occurrence of “yellow” periods with high uptake and high transpiration that make fruit carrying plants perform at their best in later phases of fruit ripening. It’s this kind of mild water shortage in such periods, where higher concentration of compounds are being produced that give fruits a flavourful taste.

This data and insights give growers valuable tools to manage and optimize water use, yield and fruit quality. No more watery tasting fruits like those low-quality greenhouse tomatoes.

Knowing when it’s time to harvest

One final example that we will cover in this blogpost is about cherries, but it’s also relevant for many other pome fruits. All fruits stop growing at a certain point, but fruits such as cherries, will clearly even shrink when they are softening due to ripeness.

cherry ripening process measured

As a grower, when you see the growth curve is flattening, you can anticipate that you will soon be harvesting and you can learn about the ideal timing to do so.

Combining dendrometers with other sensors

As always, these measurements can be combined with any other sensor in the Crodeon shop. The Crodeon Reporter transmits the data wirelessly to the Crodeon Dashboard, where you can view it using any device or process it using our APIs or Microsoft Excel. The Reporter makes the power of data accessible to companies of all sizes, even the smallest fruit grower.

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