Interview with Pierre Bakker about newly developed potato test field harvester

A major part of the applied research of the business unit Applied Arable & Vegetable Farming of Wageningen University & Research involves potato cultivation. Having the most reliable possible determination of yield per trial field plot is very important to ensure successful tests.

The large numbers involved and the often large-scale tests are currently processed in two stages; first, the gross excess rows between the fields are removed, and then the cleared net fields are harvested per field using a harvester. Pierre Bakker, manager of the testing location in Lelystad, was convinced that there must be a better and more efficient method. Together with his team he developed an entirely new trial field harvester.

Can you describe what this test field harvester does?
The trial field harvester harvests the net potato test field without the gross excess rows having to be removed first. The harvester is pulled by a tractor with GPS and a start-stop system. Start-stop means that the dimensions and locations of the fields are entered into the tractor computer, after which the tractor stops automatically and switches on the operating system of the test field harvester at the start of each field. As a result, the harvesting unit drops vertically into the potato rows before going into the harvesting position.

The tractor then starts moving forward, the conveyor and sieving belts start to rotate, and the potatoes are transported over the conveyor belt to a collection container. From this container, there is a belt to  boxes, which are filled to weight and provided with a field label. The full boxes are then placed on a pallet on the back of the machine. At the end of the field, the the harvesting unit is automatically lifted and the scraper sweeps the last potatoes from the Unit onto to the conveyor belt.

What is the essential difference with the existing method?
Until now we had been using two machines. The first removes the gross excess rows, while the second, a harvester, harvests the net fields. With the new machine, we can harvest the fields whenever we want without having to remove the gross excess rows first. The remaining potatoes in these margins can be removed at a later time with a standard commercial potato harvester. This makes the work more flexible while employing fewer machines and people.

Why was this change needed?
The number of potato field trials has increased considerably over recent years. This demands more capacity and efficiency. The new machine allows us to harvest more plots consecutively without stopping to remove the boxes. Moreover, activities can now be performed by one less person. This provides us with greater flexibility to align our activities to the conditions. In addition, the existing machine was in need of replacement.

How was the development realised?
The development was realised by applying precision GPS. It allows us to make a grid of lines on which we can enter our test field with a high degree of precision. Based on these lines the tractor receives a signal where and when it should start and stop.

What is the main benefit for clients?
The new technique means we can improve the timeliness and flexibility of test field harvesting, allowing us to harvest when the conditions are optimal. This, in turn, enhances the quality of the results. 

Are there any other plans for innovations in the field of test field techniques?
We plan to build equipment for application of fertilisers, granulates and liquids on various seeding and harvesting machines so that we can apply these substances precisely, efficiently and flexibly per field when laying them out. For tests with grains, grasses, legumes and the like, we will develop a small tractor with GPS for the development and the exact positioning and seizing of  the test fields, allowing us to combine efficiency and speed with a high level of precision.