Yield mapping root crops: from weighing to counting?

GRT Yield Monitor Grimme Harvester 3 - Photo Greentronics
GRT Yield Monitor Grimme Harvester 3 - Photo Greentronics

If you want to know what’s been going on on your fields, yield mapping is the way to go. Tried and proven in combinable crops but still challenging in root crops.

Automated yield mapping or monitoring has now been available to farmers and contractors for 30 years. On combines that is. American manufacturer Ag Leader introduced the first on-the-go yield monitor in 1992. In 1996, the company added a GPS component allowing yield data to be tied spatially and to produce yield maps. It led to what we now refer to as precision farming or precision agriculture. As of then, farmers were able to quantify the variation and the uniformity of their crops objectively. A good example of how farmers can benefit from those data, is provided by Pitstick Farms in Illinois that has been gathering farm, field and yield data since 1996.

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This photo was taken exactly 10 years ago. It shows a load cell underneath the web filling the bunker of a AVR Puma+ self-propelled potato harvester of Van den Borne Potatoes in The Netherlands. After the wet season of 2012, a second set of load cells was added to the return of the web to account for soil residues.  - Photo: René Koerhuis
This photo was taken exactly 10 years ago. It shows a load cell underneath the web filling the bunker of a AVR Puma+ self-propelled potato harvester of Van den Borne Potatoes in The Netherlands. After the wet season of 2012, a second set of load cells was added to the return of the web to account for soil residues. - Photo: René Koerhuis

Evaluate growing seasons

Mapping yields is a good way of evaluating a growing season. The yield quantity and quality represent the outcome, the effects, of choosing certain seed varieties, fertilisation, crop protection, irrigation and of course also the weather. On combines that is relatively easy as the crop is clean(ed) and quite easy to classify. Root crop yield monitoring on the other hand brings a whole lot of other challenges. Including crop and soil residues.

Dutch precision ag pioneer Van den Borne Potatoes has been mapping potato yields for nearly 20 years now. Initially by measuring the force exerted to a roller underneath the web that fills the bunker of a self-propelled potato harvester. By combining these forces with the speed of the roller and the GPS position, it allowed for mapping gross potato yields. Since 2013, the farmer has been using a load cell system instead. That system was initially developed in cooperation with Dutch specialist Probotiq. Although the company Probotiq no longer exists, their YieldMasterPRO system still is available from Dutch Trimble importer Vantage Agrometius. It is used to map the yield of various types of crops including root crops such as potatoes, carrots, flower bulbs, onions and sugar beets.

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A picture from the same day and harvester showing the yield monitored by the YieldMasterPRO system at Van den Borne Potatoes.  - Photo: René Koerhuis
A picture from the same day and harvester showing the yield monitored by the YieldMasterPRO system at Van den Borne Potatoes. - Photo: René Koerhuis

Cameras count and classify

By adding a (machine) vision component to a yield monitoring system, the yield data can be enriched to great extent. Cameras cannot only provide insights in the amount of crop and soil residue within a constant flow of product. They can also help determine the size of tubers on a web, in two and sometimes even in three dimensions. Apart from compensating gross yields for residues, algorithms enable the classification of potato (and other) yields and obtain information about the size distribution. Thus providing very valuable data to growers. Not only to growers of seed potatoes, but also to growers of ware potatoes.

Research on the added value of machine vision for potato yield mapping dates back at least two decades when Wageningen University & Research published several articles and theses about it. That same institution started a research project in 2019 to reinitiate the technology benefitting from today’s computing power and wireless data transfer. Although the results were promising, the development is ceased because of a patent application on using camera technology for root crop yield monitoring by the British-Indian company behind HarvestEye.

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YieldMonitor Isobus UT JD2630
YieldMonitor Isobus UT JD2630

These weigh-cell systems are available

YieldMasterPRO isn’t the only system relying on weigh-cells to obtain harvest data. Other systems include those of Advanced Technology Viticulture (Australia), Greentronics (Canada), Juniper Systems/HarvestMaster (USA/UK) and Topcon (USA). Future Farming approached these system providers and, in the table, below you can find more technical data about the companies that responded to our questions.

ManufacturerGreentronicsTopcon
SystemRiteYieldYieldTrakk
Suitable for (harvesters)Most brands and modelsAny harvester that has either a bunker or belt
Suitable for (crops)Potatoes, sweet potatoes, sugar beets, onions, carrots and grapesPotatoes, sugar beets, tomatoes, onions, sugarcane, pumpkins, carrots, chicory, grapes, garlic, et cetera
Number of load cells requiredUsually two load cells. One, three and four load cell systems also availableTwo load cells on a conveyor belt. Three, four or six on a bunker/hopper depending on design and size
Compensation for residuesNo real-time compensationNo real-time compensation
Yield data format.csv formatISO-XML format
Suitable for imperial/metric? You can choose a range of unitsYes
Recommended retail priceFrom CAD $8,900From € 4,000 in Europe (just the kit, no console/GNSS/fitting)
InformationGreentronicsTopcon
Koerhuis
René Koerhuis Precision Farming Specialist



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