Jensma Agro reduces labour costs with Optica Q for seed potatoes

Situated along the historic Oudebildtdijk on the Wadden Sea coast, Jensma Agro is a well-established arable farming business. At the end of February, activity at the farm is relatively quiet, giving Hessel Jensma time to welcome visitors. Every now and then, a truck arrives to load seed potatoes. The grading line has been idle for several weeks, as most of the seed potatoes have already been sorted and are stored in cold storage.

Only a small portion of the crop still needs to be graded, but the company is waiting for orders from the seed potato trading houses. Potato processors have been slow in issuing contracts this season, causing seed potato companies to delay their call-offs. As a result, grading, bagging and delivering the remaining seed potatoes will most likely coincide with the spring fieldwork.

Family business

Jensma Agro is a family-owned company run by brothers Sjoerd and Gerlof together with their nephews Andries, Jan Syds and Sjoerd Watze. The latter three are the sons of Goffe, brother of Sjoerd and Gerlof, who left the partnership in 2018. Hessel, Gerlof's son, is employed by Jensma Agro and is expected to join the partnership in the future. Besides Hessel, the company employs two permanent staff members and regularly works with self-employed contractors and temporary workers. The business operates from three main locations in Westhoek, Sint Jacobiparochie and Oude Bildtzijl. Jensma Agro grows seed potatoes for HZPC, Averis Seeds, Agrico and Europlant. The largest variety is Innovator, while other varieties include Lugano, Donata and Avamond.

Jensma Agro (Westhoek, Friesland)

Total area: 580 ha

Seed potatoes: 223 ha

Ware potatoes: 14 ha

Sugar beet: 82 ha

Onions: 48 ha

Winter wheat: 186 ha

Winter carrots: 17 ha

Fallow land: 12 ha

Tolsma-Grisnich Optica Q

Last year, Jensma Agro invested in two Tolsma-Grisnich Optica Q optical quality sorters. In addition, the company purchased a Smart Grader oversize separator and a second-hand fully automatic bagging line.The goal of these investments is to process more seed potatoes with fewer employees. During the selection process, two brands were considered, but the company ultimately chose the Tolsma-Grisnich Optica Q. According to Hessel, one of its major advantages is the three-way separation system, with separate outlets for the product flow, animal feed and clods. A major competitor combines the animal feed and clod fraction into one stream. "That combined stream would then have to pass through another separate unit afterwards to split it into animal feed and clods again."

Satisfied with the quality sorters

Around 30 tonnes of seed potatoes per hour are inspected for quality. "One Optica Q performs the work of approximately three people, and we have two of them," Hessel explains enthusiastically. "The entire grading line has been designed so that the potatoes can follow different routes. They almost always pass through the Optica Q units before entering the inspection room for a final manual check. However, they can also bypass the Optica Q units or the inspection room if required." The inspection room itself has remained unchanged and still contains two inspection belts. "Nowadays we often have just one person working at one inspection belt. When we process more difficult batches, we assign two people to one belt so they can inspect the potatoes from both sides."

Hessel is highly satisfied with the performance of the quality sorters. "They remove clods, cut potatoes and damaged tubers almost flawlessly. When it comes to other defects, I prefer not to set the machine too strictly, as that would reject too many potatoes unnecessarily. I'd rather remove those manually in the inspection room. This allows us to inspect much more selectively."

Room for improvement

According to Hessel, there is still room for further optimisation. "Previously, especially when grading the 28–35 mm size with many clods, everyone was called in to remove clods by hand. It took a lot of time and labour, and it wasn't really potato inspection," Hessel explains. "Nowadays we hardly encounter any clods at all in the inspection room."

Even so, Hessel believes there are still improvements to be made. Damage at the heel or rose end of a tuber is more difficult for the Optica Q to detect because the cameras are positioned directly above the product. Tubers with small holes also remain a challenge. "At the moment it's often all or nothing. Even the slightest sign of a small hole causes the machine to reject the tuber. But if you reduce the sensitivity of the parameters, almost everything ends up in the inspection room. The software still needs some refinement in that area." Despite this, Hessel is confident that these improvements will be made over the coming years. There's a strong team behind the machine, backed up by excellent service.

A perfect year to invest

Hessel prefers not to disclose the exact investment amount in the trade magazine, but confirms that the total investment amounted to several hundred thousand euros. The 2023–2024 season proved to be an ideal time for such an investment. Seed potato prices were exceptionally high, and because the installations qualified for the Dutch MIA/Vamil environmental investment tax schemes, the investment also offered significant tax advantages.

One of the unique features of the installation at Jensma Agro is that the two quality sorters can operate both in parallel and in series. "This allows us to sort large volumes at high capacity using both machines, or process difficult batches by running them through both machines consecutively." Due to technical reasons, they were not yet able to use the latter option during the first season.

The grading process has become considerably faster. Previously, the inspection room was the bottleneck. Today, the limiting factor is the grading machine itself. The grading machine has a capacity of 25 tonnes per hour, while each Optica Q processes 15 tonnes per hour. Together, the two quality sorters achieve a combined capacity of 30 tonnes per hour. To keep up with the increased capacity, the grading machine now continues running during coffee and lunch breaks and is often switched off around 6:30 p.m., simply to allow the inspection team to keep pace.

Quality sorters installed above the inspection room

The quality sorters have been installed in an unusual location: high above the inspection room. Originally, Jensma Agro planned to construct a new storage building and relocate the bagging line and quality sorters there. This would have created a more spacious layout and improved working conditions, although it would not have increased capacity. When construction costs turned out to be much higher than expected, the plans for a new building were postponed. Instead, the partners decided to install the quality sorters above the existing inspection room, where sufficient space was available.

Overall, Hessel is satisfied with the design. Looking back, there are two small things we would have done differently. The platform supporting the quality sorters should have been installed approximately half a metre higher. The conveyor belts carrying clods and animal feed run underneath it. "If a bearing fails, access is rather difficult."

Opportunities for future growth

Another point for improvement concerns the feed conveyors leading to the Optica Q units. Previously, a slatted conveyor allowed dust to fall through before the potatoes reached the inspection area. The current enclosed conveyors transport the dust all the way to the top of the installation, where it only falls off at the end of the discharge conveyor shared by both Optica Q units. At present, a wheelbarrow is positioned underneath to collect the dust and has to be emptied regularly. A separate conveyor will eventually be installed to transport the dust directly to the clod discharge chute.

Jensma Agro currently grows approximately 220 hectares of seed potatoes. Thanks to the modernisation of the grading and inspection line, Hessel sees clear opportunities to expand the seed potato acreage further in the coming years.

Source: Jensma Agro bespaart arbeid met optische sorteerders pootaardappelen - Boerderij