Taking steps towards real-time spraying and fertiliser application

With today's technology, driving the sprayer is a skill in itself.
With today's technology, driving the sprayer is a skill in itself.

Dutch grower Pim Sturm is aiming to spray site-specific and apply fertiliser using real-time cameras.

Since the beginning of this season, he has been using the BBLeap system on the sprayer tractor and images are collected with the help of cameras during spraying. In addition to cameras at nozzle level, Sturm has an Augmenta crop camera mounted on the front of the tractor.

Sturm’s Augmenta crop camera was supplied by Raven Europe. The crop camera scans the vegetation index (green density) in relation to biomass (ndvi). Combined with light intensity and environmental sensors, the crop sensor generates an Augmenta index.

The camera can therefore replace, but also supplement, images from drones, satellites and sensors. These instruments all have their limitations. It is good to know that the camera can see 20 metres in front and 40 metres in width (resolution accurate to 10 cm).

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The Augmenta crop camera scans the vegetation index (green density) related to biomass (ndvi).
The Augmenta crop camera scans the vegetation index (green density) related to biomass (ndvi).

Collecting data

Sturm shared his experiences with a second user, Dutch grower Nico Knibbe. The approach of both men is to apply variable amounts of fertiliser (nitrogen) in this first year. The amount of foliage is an indication of how much fertiliser is needed. Other precision applications are the variable deployment of growth regulators (ripening) and fungicides.

Sturm: “We are working on all sides to collect data so that we can control machines in real time. We then skip the step of loading images and making our own application maps”.

Improvements underway

The first impression is that there is still much to be improved. Knibbe has noticed that the images he takes with his drone are more detailed. “Maybe it works well elsewhere in Europe, but apparently our circumstances or requirements are different. I do apply 10% less fertiliser, but I do not have the impression that it is based on variable application. When the field is green, the image saturates. Also, it sometimes stops scanning when the sun is lower”, says Knibbe. Sturm agrees with these findings.

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The collected data is sent to BBLeap. The aim is to use the images this year or next year for haulm destruction in potatoes.
The collected data is sent to BBLeap. The aim is to use the images this year or next year for haulm destruction in potatoes.

Arjan Uijterlinde of Raven says he is happy with Knibbe’s feedback. Although the camera is field-ready – it works with a growing crop – there is still much more to be gained from it. Augmenta is continuously working to expand the algorithms. One addition is the use of red edge spectrum. This allows NDRE measurements to be performed with less saturation. The sensor is already equipped with it, but it is not yet used in the Augmenta index. According to Uijterlinde, this will soon be available.

Next year, the Augmenta sensor will be able to work in the dark and in twilight

The problem with the low sun is known and can be explained. Other sensors will also have this problem; the Field Analyzer switches itself off if the measurement is not accurate enough. Uijterlinde: “The leaf colour is then different and cast shadow can disturb the measurement, the luxmeter on the camera can provide correction. Here, too, it is important to expand the algorithms. Next year, the Augmenta sensor will be able to work in the dark and in twilight.”

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There are two different types of camera on the spray boom: one that takes images that the naked eye can also see and two biomass sensors (with a much shorter range than the Augmenta camera).
There are two different types of camera on the spray boom: one that takes images that the naked eye can also see and two biomass sensors (with a much shorter range than the Augmenta camera).

Cameras on the sprayer

Back to Sturm’s sprayer. There are two different camera types on the sprayer boom: one that takes images that the naked eye can also see and two biomass sensors (with a much shorter range than the Augmenta camera). The collected data is sent to Peter Millenaar of BBLeap. “The aim is to use the images this year or next year for haulm destruction in potatoes. The speed of algorithm development determines when applications will be possible”, Millenaar says.

​We want to break the trend that data is not available when an idea emerges

Meanwhile, images of other crops are also being scanned, such as onions, beets, tulips and weeds. He comments that a large database is essential. “We want to break the trend that data is not available when an idea emerges. Algorithm developers are always lacking data. Moreover, the grower can now look back at an entire season to see how crops responded to cultivation measures and conditions.”

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Each nozzle is switched on separately and even the output is variable (indicated in percentage).
Each nozzle is switched on separately and even the output is variable (indicated in percentage).

Not a drop too much

In the meantime, Sturm’s employee does his daily rounds on the field sprayer and is extremely satisfied with the BBLeap. “We don’t spray a drop too much. I enter the size of the field, fill the tank and apply exactly 150 litres per ha”.

In the past, the sprayer controlled sections of three nozzles at 1.5 metres. Now, each nozzle is switched on separately and even the output is variable (indicated in percentage). This is ideal at sloping angles, where the monitor indicates which overlap is now being avoided. But also at headland turns, where nozzles at the end of the boom give more output than nozzles closer to the tractor.

“It’s not difficult to master the control system, which started with GPS,” says the employee. The fact that it works so accurately is also very satisfying, he says.

Van Der Meer
Marga Van Der Meer Arable writer



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