It has long been believed that recycled plastic is too contaminated to use for packaging food, but new research proves the opposite. ‘The study shows that recycled plastic can be perfectly clean.’
CLOSING THE CYCLE WITH YOUR NEIGHBOUR
Many Dutch livestock and arable farmers have long collaborated through land exchange. This can benefit nature and the environment, but the results are hard to verify. ‘We need independent measurements and calculations.’
THE EEL IS IN TROUBLE
The eel has been having a hard time for decades. Hydroelectric plants, pumping stations and locks still form major barriers for this mysterious migratory fish. ‘Sadly, we’re only seeing moderate success at most fish passages.’
COLOPHON Wageningen World is the magazine for associates and alumni of Wageningen University & Research Publisher Wageningen University & Research
Editorial board: Ben Geerlings, Margit Govers, Marleen den Hartog, Miriam Haukes, Marieke Reijneker, Antoinette Thijssen, Laurens Tijink. Magazine editor Miranda Bettonville Copy editor Rik Nijland Translators Clare McGregor, Clare Wilkinson Art direction Petra Siebelink Design Monique Chermin Cover picture ANP Overall design Hemels Publishers Printer Tuijtel, Werkendam ISSN 2212-9928 Address Wageningen Campus, Droevendaalsesteeg 4, 6708 PB Wageningen, telephone +31 317 48 40 20, wageningen.world@wur.nl Change of address alumni alumni@wur.nl Change of address associates wageningen.world@wur.nl, mentioning code on adress label Change of career details alumni@wur.nl
The mission of Wageningen University & Research is “To explore the potential of nature to improve the quality of life”. Under the banner Wageningen University & Research, Wageningen University and the specialised research institutes of the Wageningen Research Foundation have joined forces in contributing to finding solutions to important questions in the domain of healthy food and living environment. With its roughly 30 branches, 7,700 employees (7,000 fte), 2,500 PhD and EngD candidates, 13,100 students and over 150,000 participants to WUR’s Life Long Learning, Wageningen University & Research is one of the leading organisations in its domain. The unique Wageningen approach lies in its integrated approach to issues and the collaboration between different disciplines.
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UPDATE
News in brief about research and development at Wageningen University & Research.
COTTON FROM HOLLAND!
In a greenhouse in the Dutch town of Bleiswijk, researchers are growing cotton. Using 95 per cent less water and zero chemical pesticides, and getting a far higher yield than traditional methods do.
DNA IN THE AIR BETRAYS ANIMAL LIFE
Animal material can be captured in an air filter and its DNA can then be analysed. This provides a picture of which animals live in the vicinity.
REMOVING MEDICINE RESIDUES FROM WATER
A new Wageningen water purification technique, developed in part by Royal Haskoning DHV, removes up to 90 per cent of medicine residues from sewage.
AUTONOMOUS GREENHOUSE CHALLENGE
In the greenhouses in Bleiswijk, five teams are competing for the title ‘best autonomous grower’.
INSURING CROPS THROUGH PHOTOS
A new insurance system in which they take photos of their crops with their smartphones offers small farmers in remote areas more security.
‘The time for action is now’
‘Angry farmers on tractors in France, Spain and The Hague, and on the other hand, anger about the way EU agricultural subsidies are wasted and about obstruction of environmental legislation. Where do we go from here?
‘At the request of the President of the European Commission Ursula von der Leyen, representatives of farmers, banks, companies, NGOs and research institutes – myself among them – put their heads together this year to address this question. They discussed future EU agricultural policy. How can the food system be made more sustainable while still offering farmers attractive prospects?
‘Right from day one of this Strategic Dialogue, all the participants agreed on one thing: ‘The status quo is not an option, the time for action is now’. A consensus on priorities was quickly reached: we need to produce enough food, improve animal welfare, simplify legislation and reduce administrative pressure – and all while ensuring that farmers earn a decent income.
LIFE
Judith Evenaar plucked up courage and started a Dutch truffle orchard. ‘I think I’ve become a bit of a truffle junkie.’
‘WURTH-WHILE FELT LIKE A GIFT’
The WURth-while programme offers refugees the chance to take courses at Wageningen University & Research.
ALUMNI
Information
An
‘But those things don’t automatically go together. So, in order to achieve as much as possible, the group advises the EU to steer more firmly. And to radically change the way it allocates agricultural subsidies: instead of paying per hectare, – causing 80 per cent of the funding to go to the 20 per cent of farms in the largest category – the subsidies should provide income support to farmers who can prove they need it. With a separate fund for sustainability initiatives.
‘More than 100 pages of recommendations from this Strategic Dialogue are now in the briefcase of the new European Commissioner for agriculture Christophe Hansen, who will base his recently announced vision for his first 100 days in office on it.
‘There is an opportunity here for the Netherlands to expand our agricultural sector’s strong position, in line with these recommendations, by moving quickly and wisely towards greater sustainability. But then we’ve got to get going. Within our ecological limits, we’ve got to build on the Dutch sector’s position as a knowledge leader. The advisory report says that we should invest more in research and education. Because there’s an urgent need for new knowledge. Let’s take this advice to heart here in the Netherlands.’
Sjoukje Heimovaara, President of Wageningen University & Research
PHOTO DUNCAN DE FEY
Brains stay young longer with a healthy diet
A carefully chosen diet plays an important role in healthy cognitive ageing. This is shown by research with which Annick van Soest obtained her PhD this summer in Wageningen.
Previous research on cognitive ageing focused on individual nutrients, such as omega-3 fatty acids, which play an
BIO-INFORMATICS
Old DNA in new plants
Old soil layers may be hiding a treasure trove of genes from ancient crops and microbes. With funding of 78 million euros, a European consortium is going to attempt to extract that information and use it to develop new climate- and disease-resistant crops. An important part of the AEGIS research project is the creation of an international centre for environmental genomics research at Copenhagen University. The DNA will be analysed in Wageningen by the Bioinformatics chair group led by Professor Marnix Medema. Info: marnix.medema@wur.nl
important role in healthy cognitive ageing, says Van Soest, who conducted her research in the Human Nutrition & Health
PLANT BREEDING
department. ‘But if we administer these nutrients to test subjects as supplements, the e ect disappears. The key seems to be the combination of nutrients. In my PhD thesis, I shift the focus from individual nutrients to the combination of nutrients.’
She used the EAT-Lancet diet as the benchmark for her research. It contains all the nutrients that are known to be important for healthy cognitive ageing, says Van Soest. ‘A bit of sh for the omega-3 fatty acids, lots of fruit and vegetables for antioxidants and polyphenols and some animal products for vitamin B12. It also has a lot of wholemeal products, nuts, vegetable oil and pulses for vitamins B and E.’ She assessed nutrition questionnaires lled in by the research participants and scored everyone on how well their diets complied with the EAT-Lancet diet. She compared this against the results of tests for brain health. ‘Our research shows that the closer people keep to the EAT-Lancet diet, the slower the deterioration in their cognitive health. And we saw this correlation within just two years.’
Info: lisette.degroot@wur.nl
Breakthrough in the battle against banana diseases
Researchers from WUR together with Chiquita, KeyGene and MusaRadix have developed a banana plant that is resistant to two destructive diseases, TR4 and Black Sigatoka. They are a serious threat to banana production.
To develop the resistant banana – dubbed Yelloway One – the researchers used a combination of conventional crossing techniques and modern DNA analysis. Professor of Phytopathology
Gert Kema calls it a breakthrough: ‘Introducing resistant and genetically diverse varieties lets us help make banana production more sustainable and
reduces the impact of diseases.’
Field tests in the Philippines and Indonesia – where TR4 and Black Sigatoka cause a lot of damage – will show how well the plant does in a natural environment.
Info: gert.kema@wur.nl
Neonicotinoids are also harmful to birds
Birds are greatly affected by neonicotinoids. Exposure to these pesticides can make migrating birds lose their way, for example.
This was shown in an analysis of almost 50 studies on 12 bird species carried out by Elke Molenaar together with colleagues from the Netherlands Society for the Protection of Birds and others. The results were published in October in Ecology Letters. Neonicotinoids such as imidacloprid are common insecticides used in agriculture and horticulture. They have been under re for years because of their unintended harmful e ects on bees and bumblebees, for example, but they were not considered seriously toxic to birds for a long time,
according to Molenaar, PhD candidate in the Behavioural Ecology chair group. ‘Our research shows that there are direct adverse e ects when birds eat food containing neonicotinoids. These e ects should de nitely not be underestimated.’
Birds like sparrows, partridges and wild ducks not only have lower survival rates but also su er deteriorating health and negative e ects on their behaviour and reproduction. An example is reduced orientation, making migrating birds lose their way.
Info: elke.molenaar@wur.nl
CONTINUING EDUCATION
In-company training for sustainable growth
Every organization faces its own unique challenges. So, besides an extensive Continuing Education programme, Wageningen University & Research also o ers tailormade training to t the client’s speci c goals. These practical programmes draw on Wageningen’s cutting-edge expertise and technology in the eld of sustainable nutrition and the human environment to help teams grow through new insights and skills, inspired by
Polarization podcast now also available in English
Wageningen University & Research’s podcast series on polarization is now also available in English. In six episodes, the philosopher Bart Brandsma talks about what happens when scientists are confronted with an ‘us versus them’ mindset and how they can deal with it. Listeners will learn how to recognize ‘pushers’ and ‘joiners’, how a neutral silent participant can suddenly become the scapegoat and what you can do to depolarize the situation. WUR’s aim with the podcasts is to give an insight into the role scientists and other ‘neutral professionals’ play in polarization and how they can use that information to determine their strategy. The Dutch-language podcasts got a positive reception, with more than 30,000 listeners. The English-language podcast series Inside Polarization can be found on Spotify and Apple Music.
Info:laura.witlox@wur.nl
current global trends. These customized in-company training programmes can help you build a futureproof organization, address burning issues for the company, or make its business model more sustainable. Leading rms such as Cargill, Bayer and PepsiCo have already made use of Wageningen’s tailormade training programmes.
More information at https://wur.eu/incompany-training
Studying pathogenic bacteria in vegan products
Wageningen researchers have received one million euros for a study of pathogenic bacteria in vegetable products. They will use it to genetically characterize the bacteria and monitor their growth and behaviour. Over the past few years, new foods such as oat milk and vegan cheese have become increasingly popular. However, raw materials such as oats, peas and almonds can contain harmful bacteria, such as clostridium species, which produce toxic substances that can survive pasteurization. The researchers’ goal is to give manufacturers tools to suppress the pathogens.
The research project is being carried out with various partners, including the Technical University of Denmark, the Danish Veterinary and Food Administration and the food industry, and is funded by Plant2Food, a programme made possible by the Novo Nordisk Foundation.
Info: heidy.denbesten@wur.nl
Missing cauli ower has been found in Germany
A call by the Dutch Centre for Genetic Resources to send seeds of old agricultural and horticultural crops turned up five varieties that were missing from the collection. The centre is still looking for 45 traditional varieties.
A century ago, the range of species in Dutch agriculture and horticulture was a lot greater than it is today. The Dutch Centre for Genetic Resources (CGN) at Wageningen University & Research has seeds of most of the 350 traditional varieties – old plant varieties typical of the Netherlands – but material for about 50 varieties was missing. The centre received 200 samples, which allowed ve missing varieties to be added to the collection. The seeds of the runner bean Heere stokboon emigrated with a family to Canada, where the bean is still being grown. The old cauli ower variety Delftsche Groene Kortpoot was found with the aid of ChatGPT. It turned out that the variety was still being sold in Germany under the name Erfurter Zwerg. Info: lena.debruin@wur.nl
Timber construction sustainable up to 60 metres high
Building with wood is sustainable. But if you want a high-rise building, 60 metres is the maximum, according to research from Wageningen Food & Biobased Research and TU Delft.
Producing building materials such as concrete and steel generates lots of CO2 emissions. Building with timber can reduce emissions. However, high-rise buildings use a concrete column in the centre of the building for the storeys to rest on. ‘When building with timber, the column has to be thicker, because wood is weaker than concrete. The required thickness increases exponentially,’ explains researcher Arjen van Kampen at Wageningen Food & Biobased Research. The tipping point is when buildings get
higher than about 60 metres. ‘Then the bene ts of wood no longer outweigh the use of CO2-intensive materials such as steel and concrete.’
The research report ‘Biobased Raw Materials for High-rise Buildings’ was published in March 2024.
Info: martien.vandenoever@wur.nl
Woodland soil contains more nitrogen than expected
Nitrogen reserves in Dutch woodland soils have increased by an average of 40 kilograms per hectare since the 1990s, measurements from 2023 show. This is far more than the 28 kilograms assumed by scientific models.
According to the researchers, you can assume that a further ve kilograms of nitrogen is stored in the wood of the trees and an equal amount leaches into the groundwater. This leads to an annual average nitrogen deposition of about 50 kg per hectare in forests. ‘That’s a huge amount of nitrogen,’ says nitrogen expert Wim de Vries. ‘Woodlands have been getting a fast-food diet for decades.’
The measurements were made in 2023 at 127 locations, repeating measurements made in 1990 in the same areas. The Wageningen researchers presented the results in September in the trade journal Natuur, Bos en Landschap.
The results are much higher than the predictions from the Aerius model, which the public health institute RIVM bases its recommendations on; that assumes 28 kg
per year over the same period. De Vries has an explanation for the higher accumulation in woodlands: ‘According to a Wageningen PhD study from 2024, nitrogen precipitation in forests is 50 per cent higher than in open landscapes. Trees absorb a lot of gases and dust particles from the air, including nitrogen compounds.’
The nitrogen reserves in the woodland soils are leading to an imbalance in nutrients, giving species that thrive on nitrogen the upper hand. When the nitrogen washes out, the soil can acidify, which is a disaster for vulnerable vegetation. ‘If you want to prevent that,’ says forest researcher Anjo de Jong from Wageningen Environmental Research, ‘you’ll have to manage forests carefully. You can’t just cut trees down, for example, because the greenery is trapping the nitrogen.’ Info:anjo.dejong@wur.nl
What will the climate do after 2050?
Researchers have a good impression of climate change until 2050. What will happen afterwards is not as clear. How fast will sea levels rise or the permafrost thaw? And what consequences will these processes have? In the next ten years, a broad consortium of Dutch climate experts is going to assess the long-term e ects of climate change in more detail. Wageningen researchers will focus on the fate of tropical forests. The Dutch Research Council as the funding organization awarded 30 million euros to the project, called EMBRACER. Info: guido.vanderwerf@wur.nl
BIODIVERSITY
Herb-rich grassland provides ample animal feed
Sowing productive herb-rich grassland can increase the biodiversity on dairy farms without a ecting the production of animal feed, according to a study by the Louis Bolk Institute and Wageningen University & Research. Productive herb-rich grassland –a mixture of grasses, papilionaceous plants and other herbs – has grass production that is just as high as for conventional grassland, stores the same amount of CO2 in the soil and enhances the biodiversity. The researchers concluded that it provides a better basis for conserving biodiversity in agricultural areas than permanent grassland.
Info: judith.westerink@wur.nl
Customers can be tempted to eat vegetarian
If a vegetarian menu is the standard option in a restaurant, people are more likely to choose it. This was shown in a test carried out at the Utrecht restaurant De Pomp for five weeks.
Researcher Machiel Reinders from Wageningen Economic Research and his colleagues tested whether how a menu is presented has an e ect on restaurant guests’ choices. For ve weeks, the scientists made it increasingly di cult to order meat or sh with the restaurant’s surprise menu. The rst week was the baseline week when the menu was the same as before the experiment started. In week two, meat or sh was
AGRICULTURE AND THE ENVIRONMENT
the standard o er, and the menu stated ‘A vegetarian option is also available.’ Then the roles were reversed, making it successively harder each week to order meat or sh, from ‘A meat or sh option is also available’ via ‘Meat or sh options may also be available; ask the sta ’, until in the fth and nal week, guests were o ered the meat or sh option for an additional charge of ve euros. ‘The vegetarian option in the surprise menu was chosen more often in weeks three, four and ve, while just as many other vegetarian dishes on the menu were ordered.’ Reinders: ‘This psychological phenomenon is called priming: guests choose the rst option offered to them.’
Info: machiel.reinders@wur.nl
Far less greenhouse gases in circular agriculture
Greenhouse gas emissions can be reduced by 80 per cent by introducing circular agriculture and eating more plant-based food. Moreover, land use can be reduced by 60 per cent, a modelling study shows.
Food production releases greenhouse gases, creates waste and uses a lot of land. Wolfram Simon, a PhD candidate in the Farming Systems Ecology chair group, calculated what measures would make the European food system more sustainable, without creating new problems. If Europe switches to
forms of agriculture that reuse as many of the leftover raw materials as possible and create as little waste as possible, 40 per cent less agricultural land would be needed. Greenhouse gas emissions would also drop by 70 per cent. On top of that, if European consumers switch to eating more plant protein and less
meat, emissions could drop by as much as 81 per cent, and land use by 60 per cent. Simon calculated 18 scenarios to nd the most e ective ways to make the food system more sustainable. A completely plant-based diet was not one of them. In a vegan diet, shortages of vitamin B12 and omega-3 fatty acids need to be compensated. Animal products remain an e cient way of taking in those nutrients, says Simon. However, we should eat less meat and the menu should change, with chicken and sh instead of beef and eggs. ‘Forty per cent animal protein is the optimum,’ he says. ‘That is 20 per cent less than we eat now on average.’
Agricultural production should also be organized di erently. ‘Cultivate the crops where they grow best. Reuse organic waste as animal feed or compost. Minimize transport.’ The researcher also makes a case for the soya bean. It contains a lot of proteins and the right amino acids, and xes nitrogen from the air, reducing the need for fertilizer.
The study appeared in June in the scienti c journal Nature Food Info: wolfram.simon@wur.nl
GEO-INFORMATION SCIENCE
New roads detected in African rainforest
Using new detection methods that combine satellite images and artificial intelligence, researchers have mapped out almost 50,000 kilometres of new roads in the African rainforest.
Almost a quarter of the roads were built in intact forests where there were no prior signs of human in uence.
Road maps of tropical forests are based on manual digitization of satellite images and are often incomplete or outdated. Researchers from Wageningen Environmental Research developed an automated method to detect forest roads. They used deep learning technology and combined optical images and high-resolution satellite images.
The construction of new roads threatens
NATURE CONSERVATION
tropical forests, which store large amounts of carbon and are hotspots of biodiversity. That is why timely information about the construction of roads is immensely important. ‘The map will be continuously updated in the next few years,’ says PhD candidate Bart Slagter, lead author of the study. ‘We want to use the method for the rainforests in the Amazon area and in South-East Asia as well.’ The study was published in September in the scienti c journal Remote Sensing of Environment. Info: bart.slagter@wur.nl
Rhinoceros poaching continues
In the Kruger Park in South Africa, the number of rhinos has fallen drastically, while poaching remains as intense as ever. This nding comes from a study by ecologist Jasper Eikelboom and Herbert Prins, emeritus professor of Wildlife Ecology and Conservation. ‘Around the turn of the millennium, the number of animals was still around 10,000 to 12,000. Two years ago, there were only 2,500,’ says Eikelboom. The
determine
scientists used a mathematical model to determine the pressure from poachers. They saw that the percentage of poached animals remained fairly constant. ‘The absolute numbers of dead rhinos are dropping because there are fewer rhinos, but they are being poached just as much.’ Eikelboom and Prins call for smaller, well-guarded parks to turn the tide.
Info: jasper.eikelboom@wur.nl
CLIMATE ADAPTATION
Nature measures put on the map
Planting a food forest, restoring a stream to its natural course or constructing new dunes to protect the coast – these are all examples of nature-based solutions for the challenges facing society. Researchers from Wageningen have created an overview of such measures in the Netherlands in collaboration with the readers of nature news website Nature Today. The map with 55 measures is mainly intended as a source of inspiration.
Info: shannen.dill@wur.nl
SYNTHETIC BIOLOGY
Building life in the laboratory
In the next ten years, Wageningen is going to work with six other Dutch universities and organizations on transforming lifeless molecules into something living. The EVOLF project received 40 million euros in funding from the Dutch Research Council.‘We can only really understand the building principles of life if we make it ourselves. We know what components are needed to make a very basic cell, but to make them work together is an entirely new challenge,’ says Nico Claassens, associate professor of microbiology, one of the Wageningen scientists on the project.
Info: nico.claassens@wur.nl
Packaging food with recycled plastic
It has long been believed that recycled plastic is too contaminated to be used for packaging food, but new research proves the opposite. A useful finding now that the EU wants to make it compulsory for companies to use some recycled materials for packaging food. The collection of the plastic needs to be customized. ‘The best option can vary per region.’
TEXT ARNO VAN ’T HOOG ILLUSTRATIONS JEROEN MURRÉ
‘The study shows that recycled plastic can be perfectly clean’
Just open your fridge and you’ll see that plastic is the main packaging material for the food we bring home. Mixed salads, mushrooms, spreads, chicken, as well as ketchup, dairy produce and soft drinks: they are all usually packaged in plastic. Cola and ketchup are stored in PET bottles (polyethylene terephthalate), yoghurt in a polypropylene (PP) bucket, and the large plastic milk bottle is made of high-density polyethylene (HDPE). Then there are mixed plastics: salami is displayed on a thin composite tray made of PET and polyethylene (PE), and is sealed with a lm made up of various plastic layers. And most bottle tops are made of polyethylene. This diversity makes recycling challenging. In an ideal scenario, you would recycle plastic by type and colour, and then grind it up and wash it to remove food residues. Ultimately, this recycled plastic is processed into pellets with which manufacturers make new bottles, trays and foils.
But using most types of discarded plastic to make food packaging is not permitted at the moment due to risk of contamination with undesirable substances. Only PET bottles that are collected separately via deposit machines provide the raw material for new bottles. Plastic from a bucket of yoghurt, a milk bottle or a tub of ice cream does not return to the kitchen but gets a new life after recycling as a paint bucket, a garden chair, a shampoo bottle or a garbage bag. Some of the collected plastic is incinerated because it is too contaminated to be recycled, or contains too much undesirable plastic – from construction waste or toys, for instance.
INVISIBLE CONTAMINATION
The main reason we hardly recycle any food packaging into new food packaging is that contaminants are absorbed into the plastic from food and the rubbish bin and we do not accept that potential risk, says Ulphard Thoden van Velzen of Wageningen Food & Biobased Research. ‘You don’t want those substances in the plastic because of their odours and aftertaste, as well as their possible toxicity.’ Examples are limonene (citrus aroma), nonanal (rose aroma) or octocrylene (a UV lter in sunscreen).
Packaging made of polyethylene (PE) and polypropylene (PP) behaves like a sponge, absorbing substances in the fridge or the rubbish bin. And not all these substances can be rinsed out in a water bath.
‘We wanted to get a full picture of which substances enter the plastic at which stage in its use and recycling. Which volatile substances are involved, and in what quantities? Once you know that, you can estimate whether the plastic is suitable material for food packaging.’
In the InRep project that Thoden van Velzen works on, research is being done on one particular form of plastic packaging: the large white milk bottle with a handle. ‘This HDPE milk bottle is designed for recycling: the label is shrink wrapped around the bottle, and it has a blue cap. Those parts are easy to separate. What is more, these bottles are made for the Dutch supermarkets by a single company that uses one grade of plastic from one manufacturer. So every milk bottle is made of the same type of plastic. The big question was: is this quality maintained during recycling?’
SIFTING THROUGH RUBBISH
To answer this question, researchers sometimes need to sift through waste. ‘We picked up these milk bottles from the milk factory and the consumers, and we shed out bottles at the collection and sorting point to analyse them.’ In the lab, the plastic milk bottles were ground up and then measurements were taken to see which volatile substances were present. The contamination was generally not too bad, says Thoden van Velzen. ‘We saw relatively few volatile substances in milk bottles out of consumers’ plastic waste containers, even though there were all kinds of packaging in them. There were a few extra aroma substances, but not very many and nothing you couldn’t get rid of. We even saw that the number of volatile substances in the plastic tended to go down at each stage between the factory, the consumer’s home and waste processing. That was a surprise.’
There was one exception to that rule, though: milk bottles that the researchers collected from a sorting facility usually contained more volatile substances. After some detective work, the source of that contamination turned out to be the baler in which the sorted packaging is compressed into a compact bale. ‘The milk bottles are in amongst all sorts of other PE packages. Under pressure, the caps jump o and residues escape from the bottles. If a milk bottle in the baler happens to be next to a tube of sunscreen, that’s re ected in the measurements. If you want to avoid that kind of con-
tamination, you shouldn’t put the milk bottles in the baler with other packaging, but keep them separate.’
Thoden van Velzen and his colleagues simulated the recycling of used milk bottles on a small scale in the lab, to see what happens to the levels of volatile substances. ‘That entails simply grinding up, washing and drying the plastic. Then we found that the level of volatile substances was lower still, even lower than in a new milk bottle. Our jaws dropped when we saw that. We always believed that recycled plastic was dirtier than new plastic, but the opposite turned out to be true.’
The lab test is di erent to the real world, where used milk bottles are not shed out of the plastic waste and recycled.
‘It’s the principle that counts,’ says Thoden van Velzen.
‘The study shows that recycled plastic can be perfectly clean. But the costs are an obstacle. Sorters ask: who’s going to pay for that?’
COMPULSORY BLENDING
Recycled plastic cannot currently compete with cheap, virgin plastic made from oil. A proposed European regulation making blending of recycled materials compulsory in 2030 could change that. If 10 per cent of packaging material has to contain recycled materials, a market grows up spontaneously. That’s the idea. According to Thoden van Velzen, that is true, but he nevertheless notices that producers of packaging material are reluctant to invest in recycling. They are doubtful as to whether their material will be positively assessed by the food safety watchdog EFSA.
The European Food Safety Authority looks at how plastics are recycled and assesses the presence and the risks of undesirable substances.
‘I talk to numerous people in the packaging branch about separate recycling of milk bottles. The question they ask most often is: What are the chances of the EFSA making a positive recommendation? Even though I know we can produce clean plastic after recycling, I cannot make any promises. You can never completely rule out the possibility that a contaminant enters at some point, and that is a guarantee that the EFSA requires. In that case, companies say, we are not going to invest tens of millions in recycling. On the one hand, I appreciate the EFSA’s scienti c rigour, but they don’t take costs and feasibility into account.’
For optimal recycling, the collaboration of the general public is crucial too. That goes for plastic packaging as >
NEW EUROPEAN PACKAGING RULES
It’s called the PPWR, which stands for Packaging and Packaging Waste Regulation. This new European legislation aims at reducing the use of packaging material and incentivizing reuse and recycling. Because the trends are not promising: although recycling capacity grew steadily up to 2024, it is now shrinking, while the use of plastic packaging per head of the population keeps on rising. The European legislation has a variety of goals. One is to reduce the amount of plastic packaging per head by 5 per cent by 2030 and by 15 per cent by 2040. There will also be a ban from 1 January 2030 on using shrink wrap to bundle products together and on plastic packaging for amounts of fresh fruit and vegetables weighing less than 1.5 kilos. Minimization will become the norm: empty space in parcels containing online purchases will be discouraged. Finally, minimum requirements will come into force for the use of recycled plastics. This blending requirement will range from 10 per cent in food packaging to 35 per cent in other packaging.
are expected to dispose of plastic, metal and drinks cartons together in one bin. If post-collection separation is chosen, all that packaging goes into the residual waste bin and is extracted at the waste processing plant. PMD is unique in this regard, since post-collection separation is not an option for other waste ows such as paper, food and garden waste, glass and clothing. Consumers have to keep those apart and put them in the right container. Waste processors say that PMD waste that is separated at source is cleaner than packaging extracted from the residual waste, as it has been in contact with less food waste. Less contamination is good for plastic recycling, although new sorting techniques are improving post-collection separation. This system is easier for consumers, especially in neighbourhoods with high-rise blocks of ats.
IMPROVING RECYCLING
well as for other waste ows such as paper, glass, food and garden waste, bulky waste, electronics, small-scale chemical waste and construction waste. It’s important that people observe the rules and make the right choices: plastic bottles go into the recycling bin, but a length of drainpipe doesn’t.
Where and how people live also plays a role in the sorting of waste and the extent to which people can help with it, says Eveline van Leeuwen, professor of Urban Economics in Wageningen and the director of the Amsterdam Institute for Advanced Metropolitan Solutions. ‘In a at you often have less space for separating organic waste than you do in a terraced house with a garden. Personal characteristics and the environment play a role too: how much do you care about the environment, do you have time, what are the norms and values in the neighbourhood? And the possibilities are often laid down by the municipal policy. In Amsterdam, whether sorting takes place at source or after collection even varies per neighbourhood.’
In discussions about waste collection and recycling, two concepts come up a lot: source and post-collection separation of plastic, metal and drinks cartons (PMD). If a municipality opts for source separation, then residents
Which system works best under which condition is the subject of research Van Leeuwen is doing in the Dutch Research Council project MUNITION. In this project, her group is working with Nijmegen researchers on a computer model of the collection and recycling of plastic waste.
‘It’s a digital model of a town in which we bring together the factors a ecting waste separation: people, the municipality, waste processors, the neighbourhood. If we put all that into a model, we can then calculate the consequences of di erent scenarios – like source and post-collection separation – to get an idea of where there is scope to improve the recycling of plastic. Where can we make adjustments?’
There are chemists, economists and behavioural scientists working on the project. Experiments are carried out with aims such as identifying the circumstances under which people choose to separate their waste. The optimal collection system is not necessarily the one that produces the highest percentage of recycled plastic, says Van Leeuwen. The project looks beyond the yield and the purity of the polymers. ‘How to assess what’s the best system is something that we’re still working on. We compare two main scenarios – separation at source and post-collection – in terms of general welfare, so the impact on the economy as well as the environment. What are the costs for the collectors, the recycling companies, and the municipalities? The social side is addressed as well: how much do we ask of citizens and what’s in it for
‘We compare separation at source with post-collection separation to see the impact on the environment and economy’
them? And we look at the quality of the plastic collected.’
The goal is to develop a digital resource with which municipalities and waste processors can calculate the implications of di erent collection methods per municipality or neighbourhood. ‘If a municipality introduces a new waste collection system, residents have to change their behaviour, so you can’t just reverse the change two years later. What is more, it can help in explaining why there’s a di erent policy for the city centre than for the suburbs, even though one of the approaches might not have an optimal impact on the environment.’
Van Leeuwen thinks customizing the approach is more helpful than a discussion about source versus postcollection separation. ‘If you look exclusively at the quality of the recycled plastic, source separation might seem better. But if you look at the bigger picture, including the economic and social costs, then I think what the best
option is can vary per neighbourhood or region.’
According to Van Leeuwen, optimal recycling is important but the rising use of plastic packaging deserves attention too. The percentage of recycled plastic in use has increased in recent years, but the overall use of plastic packaging is outstripping it. ‘There are certainly good reasons for using plastic, for example to keep food fresh for longer. The environmental impact of food spoiling if it’s not plastic-wrapped is a consideration. But at the same time, we need to nd options for using less plastic. We’ve already found we can do without plastic bags in the supermarket and disposable cups at the university. It’s not for nothing that the motto is: reduce, reuse, recycle. First reduce use, then promote reuse, and only then recycle.’ W
www.wur.eu/recycling-food-packaging
‘Mainly, we show what the possibilities are’
Dutch cotton!
In a greenhouse in the Dutch town of Bleiswijk, researchers are growing cotton. Using 95 per cent less water and zero chemical pesticides, and getting a far higher yield than traditional methods do. The first harvest resulted in a unique pair of G-star jeans. But in the Netherlands, cotton will likely remain a niche market.
TEXT RENÉ DIDDE
Filip van Noort swings open the door of the greenhouse, revealing the distinctive u y white balls of cotton dangling from the branches wrapped in wire up to a height of four metres. High in the plants we can just detect pretty white and pink owers. ‘You’re lucky, we are harvesting,’ says the greenhouse horticulture specialist from Wageningen Plant Research in Bleiswijk.
With 100 plants on 100 square metres, this is a postage stamp among Dutch greenhouses. But Van Noort is proud of it. ‘I’ve counted more buds than last year,’ he says. In this second year that Van Noort has been working on cotton, he thinks he can as good as double the yield to nearly two kilos per square metre – or per two plants. The cotton ‘bolls’ that surround the seeds take ve
months to grow. This bright white cotton is super-clean. Last week, Van Noort hosted a visiting researcher from Pakistan, who has been working in the cotton industry for 20 years. ‘He reckons this cotton doesn’t need washing.’
2700 LITRES OF WATER
And that is just one minor advantage of growing the cotton in this South Holland greenhouse. Compared with open cultivation in China, India and the United States, Van Noorts’ plants produce between 5 and 20 times more cotton, use 95 per cent less water – in conventional open cultivation, it takes 2700 litres of water to make one short-sleeved T-shirt – and no chemical pesticides. These results are achieved by drip-feeding
the plants with harvested rainwater containing a precise dose of nutrients. Sensors measure water levels continuously. ‘At night the plants don’t get anything, in the morning we target the right water level, and in the afternoon the dosing depends on the amount of light available.’
The researchers also test di erent types of substrate such as rockwool and peat substrate containing perlite, a volcanic rock. Because the plants are not in the ground, they are not prey to soil pests and diseases. And any pest insects heading for the pink buds and white cotton bolls are dealt with by their natural enemies such as mites, bugs and lacewings.
The idea of growing cotton in a greenhouse came from the Swede Victor Sandberg, who previously worked for Levi’s, says
Van Noort. In the rst year in Bleiswijk, the plants yielded over a kilo of cotton per square metre. The Dutch jeans manufacturer G-star, who nanced the trial, spun the bres into yarn and had laps of cotton woven with it, with which the company made a – presumably una ordable – pair of jeans.
This year things are being done di erently. The next trial will be nanced by a group of progressive Dutch greenhouse horticulturalists, united as Innogrowers, together with substrate producer Grodan and G-star. Members of Innogrowers grow tomatoes, bell peppers, pot plants and strawberries. ‘These are large, wealthy companies that also collaborated on innovative cultivation of wasabi, papaya and passion fruit, which I worked on as well.’
BUSINESS MODEL
Their interest in exotic products is not as strange as it may seem, says Van Noort. ‘If we researchers get cotton plants thriving in the greenhouse, they can soon tell whether that gives them a basis for a viable business model.’ If InnoGrowers are satis ed with the yield, Van Noort expects that there will be a trial next year on the semi-commercial scale of 500 to 1000 square metres.
Robert Duijvestijn, InnoGrowers’ project coordinator, doesn’t think Dutch growers could ever compete with conventional cotton
production on price alone. But the latter guzzles water and is extremely polluting. ‘If the current cotton suppliers are ever faced with “true pricing”, it will be a very di erent matter. There’s a reason companies like G-star are taking the initiative: they are aware they’ve got to take steps towards a more sustainable production chain.’
ENERGY COSTS
Van Noort’s previous research included trials with Dutch vanilla in greenhouses. He aims to ‘develop something that the world bene ts from’, he says. He sees co ee and medicinal plants as possible new greenhouse products. He doesn’t expect cotton to be a gold mine any time soon, as open cultivation is always cheaper. Growing cotton all year round in the Netherlands is expensive because of the energy costs in winter. ‘But I do think there is a place for Dutch cotton in a niche market. Mainly, though, I show what the possibilities are. And as a result, some elements of our research will probably be applied in open cultivation. For example, growing cotton in half-open plastic greenhouses using less water, nutrients and chemicals, and much more harvested rainwater, perhaps in combination with solar panels on top of water tanks.’ W
less use of water 95% higher yields up to 23x
www.wur.eu/dutch-cotton chemical pesticides
Filip van Noort grows cotton in a greenhouse in Bleiswijk. Right: with Rebecka Sancho of G-Star, with the first pair of ‘Dutch cotton’ jeans.
Closing the cycle with your neighbour
Many Dutch livestock and arable farmers have long collaborated through land exchange. This can benefit nature and the environment, say four farmers engaged in research into their business models. But the results are hard to verify. The aim is target-centred management: environmental targets are set per farm, and the farmers decide how they will reach them.
TEXT ALBERT SIKKEMA PHOTO ALAMY / FRANS LEMMENS
In Nooitgedacht in Drenthe, dairy farmer Giske Warringa coordinates the Wageningen research project on collaboration between arable farmers and livestock farmers. ‘We said: you’re welcome to do research here, and maybe we will learn from the other four PAVEx areas.’
Giske Warringa from the village of Nooitgedacht in the province of Drenthe has made a map of the farmland in the Netherlands. And she is keen to show it, at the kitchen table at the dairy farm she and her husband Gert-Jan run. On the map, the Dutch farmland is divided into two categories: farmland that gets exchanged between farmers, and land that does not. The map shows that 37 per cent of the farmland does get exchanged. In Drenthe, more than half the land gets exchanged. That swapping of land is one of the ways in which farmers collaborate. ‘But hardly any research gets done on mixed land use,’ says Warringa, disappointedly. Warringa, who studied in Wageningen (Animal Sciences 2007), coordinates work in Drenthe on PAVEx: ‘Pilots in collaboration between Arable and Livestock farmers in ve Experimental locations for circular agriculture’. This Wageningen University & Research project was born of the policy of minister Carola Schouten, four Agriculture ministers ago. It aims to contribute to closing cycles in agriculture, in the interests of reducing the loss of nutrients, including nitrogen, and minimizing greenhouse gas emissions.
In the project, analyses are made of how arable and livestock farmers collaborate. WUR describes the collaborating farming systems and analyses the advantages for achieving the national environmental targets set by the ministry, such as reducing ammonia, nitrate and greenhouse gas emissions, as well as how prove these environmental bene ts .
‘PAVEx aims at clarifying how livestock and arable farmers collaborate, so scientists and government can understand it,’ says Warringa’s colleague in the project, farmer Geertje Enting from the nearby village of Anderen. And much more exchange of land goes on than policymakers and researchers realize, she claims. ‘Sectoral thinking, in which arable and livestock farming are two di erent worlds, is ingrained in policy at present. We argue for an agricultural policy that takes the soil as its starting point. That’s how we’ve been farming here for years!’
Enting and her husband Albert-Jan run one of the few mixed farms in the Netherlands. They have 140 dairy cows and an arable side to the farm, growing starch potatoes, fodder beets and concentrated feed for the farm’s own cows. They also exchange land with an arable farmer who grows seed potatoes on their land in exchange for elds of new grassland. In addition, they have an agreement with a farmer from the village who grows maize for them and uses their manure on his crops, from which he supplies them in turn with straw. ‘This is very normal; we grew up with it.’
MANURE FOR LIVESTOCK FEED
There used to be a lot of mixed farms in the province of Drenthe. The livestock side of the farm provided the arable side with manure in exchange for livestock feed. Thanks to specialization, mixed farms are now very much in the minority, but collaboration between livestock and arable farmers has continued in the region.
‘Collaborating with our neighbour means we can both inject less nitrogen’
The Warringas in Nooitgedacht exchange land too. They run a dairy farm with 160 cows and 120 hectares of land. They collaborate mainly with their neighbour, arable farmer Tienus Berkepies, who farms on about 170 hectares, growing mainly potatoes but also some fodder beets, grain and onions. The Warringas grow some crops themselves too, including maize and fodder beets – ‘But we let our neighbour grow the beets, because he’s the expert’ – and mixes of barley and peas. ‘We grow 80 per cent of our livestock feed ourselves.’
The collaboration between Warringa and Berkepies is all about crop rotation, whereby a di erent crop is grown in a given eld each year. By swapping elds with a livestock farmer, the crop farmer can grow the same quantity of seed crops every year, and because he grows them on new soils, he has fewer problems with pathogens. Grass is grown in rotation on exchanged land too. It is feed for the livestock, and serves as a rest crop for the arable farmer. By growing, say, potatoes for a year after four years of grass, the livestock farmer can sow new herb-rich grassland every ve years, and will not need to spray the eld with herbicide to control weeds. ‘What is more, by using animal manure, the livestock farmer builds up organic matter in the soil, with nutrients that the arable farmer uses afterwards,’ says Warringa. Every winter, they sit down with Berkepies to draw up a new joint crop plan that bene ts both parties.
CO2 PREMIUM
Warringa supplies milk to the dairy company FrieslandCampina, which has started paying farmers a CO2 premium this year. ‘We score very well on that, whereas we don’t think about CO2 at all. Our aim is to be as selfsu cient as possible and to operate in a regional closed cycle. That’s why, for instance, we buy discarded malting barley locally for livestock feed. That saves us having to buy concentrate, and that keeps our CO2 score low.’ Warringa thinks she farms pretty sustainably, but she is happy to be involved in the PAVEx study. ‘What we show is: arable farmers on sandy soils need grass as a rest crop because grassland xes organic matter in the soil, boosting its fertility. They can achieve that by sowing the land with grass for a while, and having it grazed by livestock from a local livestock farmer. An additional advantage is that with more organic matter, you retain more water in the soil. And applying this kind of crop rotation means we have fewer diseases and pests in the soil. If
we only had grassland on a permanent basis, and our neighbour only had crops on his land, we would both need to spray more pesticide. So we have said: you’re welcome to do research on our farmers, and maybe we will learn from the other four PAVEx areas how to farm even more sustainably.’
GROWING VEGETABLES
The PAVEx study on the collaboration between livestock and arable farmers is being run in ve experimental regions: North Netherlands, Flevoland, Twente, Achterhoek and De Peel. In De Peel, in the province of Brabant, the project is being coordinated by alumnus Ronald Luijkz (Animal Sciences 1987) innovation manager at Agro Proeftuin Noordoost Brabant. A lot of land exchange goes on in this area too, he says, because it is characterized by a mix of dairy and pig farms, and arable and vegetable growers. Vegetable growers are particularly specialized and need several di erent elds to keep the supermarkets supplied. So they exchange land with livestock and arable farmers. ‘I hardly know anyone who doesn’t exchange land.’
Exchanging land is also a must for tackling the challenges of farming in North-east Brabant, says Luijkx. ‘There is a lot of manure in the area, where most farmers are located on leaching-prone sandy soils, and we don’t yet meet the nitrate norms for groundwater. Arable farmers need a lot of crop rotation to keep the pressure of disease in crops like potatoes in check, and they can also improve the water quality by alternating intensive crops with extensive ones like grass, on which neighbouring livestock farmers can graze their stock.’
Since 2021, a few of the farmers involved in the project have been measuring how much nitrate is still in the soil in their elds at the end of the growing season, potentially leaching into the groundwater. Nitrate in the soil is a good indicator of both soil and surface water quality, says Luijkx. ‘We are taking measurements in all the elds on Bart Peters’ arable farm and Harm Wientjes’ dairy farm. Between them they have about 200 hectares of land, with a continuous variation in crops, and they can now link the nitrate concentration to the agricultural land use of the past few years.
So arable farmer Peters, in Sint Anthonius, with 100 hectares of chipping potatoes, maize, sugar beets and onions, now knows how much nitrate is left in the soil in the autumn. On average, his farm is within the envi- >
‘Sectoral thinking is ingrained in policy at present’
ronmental limits. But the situation does vary from one eld and crop to the next. On a eld of potatoes and vegetables, the level is generally above the limit, while on a eld of beets it is much lower. Peters has noticed that he can also reduce nitrate levels using a fertilization plan and ‘catch crops’ that x nitrate.
Peters’ fertilization plan entails using manure provided by Wientjes, a Wageningen alumnus (Agrotechnology 2006) from nearby Oploo. Wientjes and his brother have an intensive dairy farm: 300 cows on 100 hectares. They collaborate with Peters and two other local arable farmers, who get their manure in exchange for livestock feed, mainly maize. They have a joint farming plan with a ve-year cycle of grass, potatoes, beets and two years of maize. This cycle ensures the least leaching of nutrients, says Wientjes. Like Peters, he monitors the nitrate and the phosphate accumulation in the soil.
METHANE EMISSIONS
But Wientjes’ real showpiece is the manure processing plant on the farm. A manure scraper removes the manure from the barn quickly so that not much ammonia escapes. The manure then goes into a digester, which extracts biogas from it, and the residue goes to a manure separator. The solid waste, which is full of phosphate, gets reused on the farm or sold elsewhere. The liquid waste goes to a ‘stripper’, a machine that captures ammonia in the form of ammonium sulphate, a transparent liquid that can serve as a substitute for arti cial ferti-
CPI FOR TARGET-DRIVEN MANAGEMENT
WUR, the Louis Bolk Institute and the consultancy firm Boerenverstand are working on a nationwide system of Critical Performance Indicators (CPIs) for assessing and rewarding sustainability on the farm. In the ‘core set of CPIs for sustainable agriculture’, they describe 13 indicators for dairy and arable farms. The CPIs are intended to play a role in target-driven management. The agriculture sector wants to shift from stipulations about the method, in which the government prescribes specific techniques or methods for achieving environmental targets, to stipulations about targets, which lay down the target or environmental norm, leaving farmers free to achieve them in their own way. Because environmental targets are statutory, target stipulations need to be measurable and enforceable, and supervisory bodies need to be able to hold farmers accountable.
lizer. What is left is an e luent that is high in potassium and low in nitrogen. This three-stage process reduces methane emissions by 20 per cent and the amount of ammonia on the farm by 70 per cent, says Wientjes. The gures are based on WUR research.
Wientjes provides Peters with the arti cial fertilizer substitute and the e luent from his own manure, and under the auspices of PAVEx, Peters has monitored the growth of the eld crops fertilized this way. It turns out they grow just as well as they do with arti cial fertilizer. A crucial advantage of these fertilizers is that ammonia emissions during application are lower. Wientjes also measures the ammonia concentration in the barn. ‘Then I get a sense of how I could reduce losses even further, for example by removing the manure faster with the scraper.’
TARGET-DRIVEN
This kind of knowledge is useful because research is also being done in PAVEx on whether and how the collaborating circular agriculture farmers contribute to the environmental targets set by the ministry.
Like the other PAVEx participants, Wientjes is keen to move towards target-driven management in which targets are set for emissions of ammonia, greenhouse gases and nitrate on each farm. The farmers decide for themselves how they are going to meet these environmental targets. At the moment they sometimes feel hamstrung by nationally imposed blanket rules. One of these is a government ruling that arable harvests should be in by 1 October, after which farmers therefore cannot sow ‘catch crops’ that x nitrogen in the soil. This measure is an awkward t with farming practices, says Bart Peters. The potatoes are not fully ripened by the end of September, and therefore cannot be kept in storage for long. So farmers dig up their potatoes after 1 October and just accept that they will be allowed to apply less manure the next year. Because such measures hamper their farming practices, the PAVEx farmers are keen to move towards target-driven management.
Wientjes: ‘Target-driven management gives more incentive to reach environmental targets.’ In Drenthe, Warringa and Enting say the same: ‘Give us environmental targets!’ They want to decide for themselves how they cut their emissions of ammonia, nitrate and greenhouse gases to the target level, by means appropriate for their farming methods. The farmers have another wish too. In the development of target-driven management and the critical perfor-
mance indicators (CPIs) that go with it, achievements are assessed per farm, says Warringa. ‘We would also like performance indicators that take into account regional nutrient cycles and land exchange. We think the CPIs should start at the eld level and then be added up at the farm level.’
RICH SOIL LIFE
As an example, livestock farmer Warringa has relatively little permanent grassland, due to the collaboration with arable farmer Berkepies, whereas such grassland is valued highly by Friesland Campina and the Dutch forestry commission Staatsbosbeheer, due to its wealth of soil life and organic matter. Temporary grassland o ers other advantages, such as lower levels of pesticide use and many herbs that attract insects, says Warrminga, but you only really see those advantages if you look at crop rotation at the plot level. WUR is currently studying how crop rotation can be integrated into the Critical Performance Indicators.
Within the PAVEx project, research is also being done on how the farmers can demonstrate that they are meeting targets using measurements and data. ‘We need independent measurements and calculations for a legally sound veri cation of the results,’ says Ronald Luijkx. ‘In recent years, we have learned we need measurements at the plot level. That provides information that can be used to improve cultivation methods, plus we can show
the results to the authorities and defend our approach in court.’ ‘A farmer almost needs a university degree to be able to solve the environmental problems,’ jokes Wientjes, himself a science graduate. ‘But if the government is going to set targets per farm, you’ll get study groups forming and farmers will visit their neighbours to ask: how do you go about it?’
CONTRIBUTING KNOWLEDGE
And this is where Wageningen contributes useful knowledge, thinks Luijkx. ‘In our region, WUR’s experimental farm in Vredepeel plays an important role. There’s a lot of fundamental knowledge there about the di erent crops, and farmers are quick to realize that.’ In Drenthe, Warringa gets support from Brenda Timmerman-Pals, a farmer and project leader at WUR’s Farm of the Future in the former peat colony area.
Rianne van Zandbrink, a Wageningen researcher who contributes to PAVEx, thinks the project works because it focuses on the participating farmers’ learning goals. ‘The farmers, researchers and policymakers engage in genuine dialogue about what they want to learn from each other. I see that farmers have a collective inventiveness and smart ways of collaborating on things like cutting down on pesticides and concentrates, and that they are inspired by target-driven management.’ W
www.wur.eu/pavex
Dairy farmer Harm Wientjes in Oploo collaborates with three local arable farmers.
DNA in the air betrays animals
Wageningen researchers succeeded in capturing animal material in an air filter and analysing its DNA. This gave them an idea of which animals were living in the vicinity without needing to spot them or record them using camera traps. That offers potential for mapping biodiversity.
TEXT HARM TEN NAPEL PHOTOGRAPHY GUY ACKERMANS
It is a 16-kilo, crocodile-green gadget on a tripod with something on it that looks like a ship’s rudder. The Bukard Spore Trap was originally designed to lter pollen out of the air. Wageningen scientists studied whether the gadget can also be used to nd out which vertebrates inhabit an area. The animals continuously shed akes of skin, hairs, feathers and saliva – all of which contain DNA. With that DNA, the researchers hope to be able to identify animals in the vicinity without needing to spot them or capture them on camera: timeconsuming methods which can also miss a lot of small species.
The study was led by Marcel Polling, animal ecologist at Wageningen Environmental Research. ‘We weren’t the rst. In 2022, Danish researchers proved that an air sampler can capture the DNA of nearly all the animals in a zoo.’ Nor is it a new idea to analyse DNA traces from an environment: scientists have long collected information about the life present in water and soil in this way. The Wageningen study set out to establish whether an air sampler placed out in nature could also
lter su cient, reliable DNA out of the air to provide a picture of the mammals and birds present.
TAPE WITH VASELINE
The Bukard works along the lines designed by the British biologist John Malcolm Hirst in the 1950s for capturing fungal spores and pollen out of the air. In this system, the particles stick to a microscope lens covered in Vaseline. Inside the Burkard is a long roll of tape covered in a thin layer of Vaseline. ‘A mechanism rolls the tape slowly across the opening on the front of the machine, so that a new section is continuously being exposed to the air,’ explains Polling. ‘This enables the Burkard to go on collecting material for longer. You can see from the location on the tape on which day the DNA was captured.’
The weather vane above the machine ensures that the opening of the sampler is always facing the wind. In order to capture as many particles as possible, the Burkard also draws air in at the rate of about 10 litres per minute. The engine that drives the suction is powered by a solar panel on the ground next to the machine.
For their research, Polling and his colleagues positioned the Burkards for a week at each of three di erent locations: a forest, an orchard and a solar farm. Camera traps recorded the animals that passed by. ‘That enabled us to check whether the Burkard really captured DNA from animals that had been in the vicinity.’
As well as pollen, the researchers found miniscule particles of animal matter containing DNA in the Vaseline. ‘We’re not really sure whether they are bits of hair or of skin. The particles are too small for that,’ says Polling. ‘But they do contain enough DNA to analyse.’
100 BIRD SPECIES
‘We found the DNA of more than 100 bird species, dozens of mammals and a few amphibians. Surprisingly enough, there was also some sh DNA. All were sea sh, so that DNA probably came from human garbage.’ The nine mammal and seven bird species that the cameras had recorded were also found on the tape. The results were published in the scienti c journal Environmental DNA in August.
Polling’s fellow ecologists are enthusiastic about this technology, he says. Its potential for measuring biodiversity is obvious: without having to spot or capture animals, researchers can get a comprehensive impression of the diversity in an area. ‘What we don’t yet know is how wide an area the air sampler covers. How far does the DNA come from? How much DNA does there have to be in the air before it shows up in the sample? How old can the DNA be? What is the impact of the wind, exactly?’ Ongoing followup research aims to answer these questions.
MAGELLANIC PENGUIN
Not all the DNA in the samples could be accounted for. The DNA of an exotic parrot and a Japanese quail could be traced to a local pet owner, but that of the South American Magellanic penguin remains a mystery. ‘You could say that the air sampler works too well in some cases,’ says Polling. During the follow-up study too, the Burkard captured DNA from all sorts of exotic species. ‘Pets in the area, we think.’ One solution might be to measure over a shorter time. ‘So we gave people doing bird inventories a kind of handheld model of the device. Then you take a sample over an hour instead of a day. We are still waiting for the results, but with any luck, this way we will mainly capture DNA from the immediate vicinity.’ W
www.wur.eu/environmental-dna
‘We found the DNA of more than 100 bird species’
The camera trap at the installation at at Proeftuin Randwijk recorded a buzzard whose DNA was also found in an air sample.
The eel has been in trouble for decades. Research has shown that locks and pumping stations still form major obstacles for the mysterious migratory fish. Meanwhile, the prospects of being able to breed eels throughout their life cycle are gradually improving. If that works out it will no longer be necessary to catch glass eels for breeding purposes.
TEXT RENÉ DIDDE PHOTO PATRICK PLEUL AFP/ANP INFOGRAPHIC STEFFIE PADMOS
Barriers for eels
THE LIFE CYCLE OF THE EUROPEAN EEL
(Anguilla Anguilla)
The
In the experimental sh research facility at Wageningen University & Research, researcher Arjan Palstra takes o the lid of a water tank to reveal fat, dark-coloured eels swimming around in it. ‘Those are sexually mature females whose eggs will soon be released,’ says Palstra. Smaller, slender, silvery males swim inquisitively in and out of the PVC tubes placed in the basin.
Palstra and his colleague Leon Heinsbroek have been trying to close the life cycle of the European eel in captivity since 2016. The research is being done under the auspices of the Eel Reproduction Innovation Centre (EELRIC), which was set up in collaboration with the Dutch Sustainable Eel Sector foundation (DUPAN).
RELEASING EGGS
The initial aim was to get female eels that were ready to spawn to release eggs, and to fertilize the eggs with sperm from the males, in order to reach the rst larva stage on the road to becoming young glass eels. ‘We succeeded in getting the eels to produce larvae straightaway back in 2016’, says Palstra. But the larvae only survived for a few weeks. In a follow-up study, the publicprivate collaborative project LARVitAAL,
During this journey (of two to three years) they grow into glass eels of about 7 centimetres long.
In Europe, they migrate to fresh inland waters to mature.
After 10 to 30 years, the silver eels swim nearly 6000 kilometres back to spawn.
Obstacles
Obstacles such as dams, locks and pumping stations block the way for incoming glass eels and departing silver eels. Pumping stations and hydroelectric plants can even be fatal for them.
the researchers are now trying to improve the quality and health of the larvae. They are succeeding, says Palstra, thanks to innovations in the reproduction techniques. ‘Since September we have also been testing new diets to improve the growth of the larvae. We hope it will then become standard for them to reach the glass eel stage.’ If it works out, it will no longer be necessary to catch glass eels for breeding purposes. Eels are bred by 10 companies in the Netherlands. They start with wild-caught glass eels, most of them caught o the coast of France. According to gures from DUPAN, the 10 companies produced about 2000 tons of farmed eels in 2023, bred from seven tons of glass eels. For comparison: professional sheries caught 453 tons of wild eels that year.
If a completely closed eel aquaculture is achieved, that will be good news for the wild eel too, says Palstra, as it will further reduce the pressure from sheries.
GREATEST FEAT
The eel population decreased dramatically in Europe between 1980 and 2010, for no clear reason. ‘The eel is a mysterious sh with a long life cycle, most of which unfolds
out of sight for us,’ says Palstra. The sh spawns and produces larvae in the sea, but grows to adulthood in fresh water. Spawning takes place in the Sargasso Sea, nearly 6000 kilometres from the Netherlands. Then the larvae perform their greatest feat by hitching a ride on the gulf stream to the European coast, where they undergo a metamorphosis and change into small, transparent glass eels. Once they are back in Europe, the eels smell fresh water, but they have great di culty in reaching the inland waters due to hundreds of obstacles in the form of dams, locks and pumping stations. And these obstacles later form a barrier for the adult eels – known as silver eels – that head back to the sea in order to swim to the Sargasso Sea. Pumping stations and hydroelectric plants can even be deadly. In spite of improvements made to them in recent decades, these installations are still all too often a mincing machine for sh. In other countries too, such as Spain and Sweden, the numerous hydroelectric plants block the eels’ progress. But these are not the only reasons for the decline of eel populations. Researchers point to pollution of the major rivers, and to the swim bladder parasite, which slows the eels’ growth and undermines their tness
The eel spawns in the Sargasso Sea and then dies.
larvae are carried to the European coast by the Gulf Stream.
‘Eel stocks in the Netherlands don’t tell you much about the population as a whole’
for swimming back to the Sargasso Sea. Eel sheries also play a role in falling eel stocks.
EUROPEAN RESEARCH
Palstra is part of a group of about 30 Wageningen scientists who work on the eel from di erent angles, including ecology and the pollution of its habitat, breeding and reproduction, eel-related policy and the sheries economy. ‘In spite of all the scienti c research on the European eel, it is impossible to pinpoint a single cause for its signi cant decline since the 1980s,’ says Tessa van der Hammen, a researcher at Wageningen Marine Research. Van der Hammen is the project leader for the Netherlands’ statutory EU research tasks aimed at supporting the eel. In this context, Van der Hammen is doing data research on the size of current eel stocks. ‘Let’s just say that the decline is caused by a cocktail of factors. In eel conservation, the sheries are usually the rst to come under scrutiny, but we need to address all the causes of the decline.’
Eel sheries in the Netherlands have dwindled, although scientists don’t have a clear picture of the extent of illegal shing. ‘There is a shing ban from September to December to give the silver eels the chance to leave for the Sargasso Sea. And there’s a total ban on shing for eels in the rivers because of pollution,’ explains Van der Hammen. In 2023, professional sheries caught 453 tons of eels, 282 tons of them in the IJsselmeer and Markermeer lakes. About 50 years ago, over 1000 tons of eels were routinely caught in the IJsselmeer alone. What makes managing eel sheries tricky is that the sh’s habitat extends from North Africa to Iceland, says Van der Hammen. ‘That means that all the countries must join
forces to protect the eel.’ For that reason, an ‘eel regulation’ has been in place in the EU since 2007, in which every member state is required to make a national and regional eel management plan. The regulation includes a shing ban during the three months of the silver eel migration; a ban on anglers keeping the eels they catch; restocking inland waters with glass eels; and making adjustments to turbines and locks so that the sh can pass through them.
‘The long-term goal of the eel regulation is for over 40 per cent of the historical population of silver eels in every member state to be able to migrate to the sea to reproduce. Since eels are a long-lived species, recovery is expected to be slow and the EU focuses on whether the trend is in the right direction.’
EEL STOCKS
The Wageningen researchers provide the EU with an estimate of the eel stocks every three years, to show how far the Netherlands is from the agreed goal. To this end, sampling is done in inland waters such as the IJsselmeer and the major rivers.
‘Particularly in the IJsselmeer, there is a clear increase in the number of large eels,’ says Van der Hammen. Such a rise has not been observed in all the countries, however. ‘The methods of establishing eel stocks vary a lot per member state, making it hard to draw comparisons,’ she says.
As a consequence, the International Council for Exploration of the Sea (ICES) focuses mainly on the numbers of glass eels returning to European shores from the spawning grounds. ‘By comparing those numbers with previous years, you can nd out whether there’s a rising or falling trend in overall European stocks.’ >
ARJAN PALSTRA Senior researcher on fish physiology and aquaculture Wageningen Livestock Research
TESSA VAN DER HAMMEN
Eel researcher and project leader, Wageningen Marine Research
The estimates are surrounded by many uncertainties, but according to Van der Hammen, the decline in eel stocks in Europe has been halted over the past decade. ‘But the supply of glass eels from the spawning grounds is still very low all over Europe, compared to what it was.’
RESTOCKING
To boost eel stocks in the Netherlands, and with funding from the ministry of Agriculture, Fisheries, Food Security and Nature, DUPAN released glass eels purchased in France in parts of the Netherlands including Friesland and the string of lakes along the border of Flevoland province, explains Van der Hammen. It remains to be seen whether these eels originating from France will manage to reach the Sargasso Sea from the Netherlands, says Ben Gri oen, a PhD candidate in the Aquaculture & Fisheries chair group. Gri oen does research on the migration of sh including eels at Wageningen Marine Research in Ijmuiden. He also helps monitor the glass eels at so-called junctions, where the little sh reach Dutch inland waters in early March after a long journey. ‘The glass
eel is often smarter than we think,’ says Gri oen. ‘If it can’t access the inland waters at Katwijk, the young sh will just try again at IJmuiden or the Afsluitdijk.’ He has also repeatedly seen that glass eels quite easily slip through with ships going to Amsterdam via the locks at IJmuiden. ‘Especially if the locks are opened in the evening, the eels can easily get in,’ he says.
For his research commissioned by the ministry of Agriculture, and the national and regional water boards, Gri oen catches glass eels and colour-codes them (under anaesthetic) with di erent colours per time and place. The transparent little sh are about two years old at that point, and about seven centimetres long. ‘They are still too small to have a transmitter attached to them, which is why we colour-code them in order to track them along their route towards fresh waters.’ In the last couple of years, more than 150,000 glass eels have been colour-coded. ‘We are trying to nd out how many glass eels there are, how long they get are held back for by obstacles like locks, and whether they can get through in the end.’
To nd out how the sh continue to migrate through an area, the researchers
released thousands of colour-coded glass eels in several batches at locations including IJmuiden harbour. ‘We saw in the North Sea Canal, for example, that glass eels get in all right, but once they are in the canal there are bottlenecks at the various locks into the hinterland. Some of the sh passages work well, such as the one at Halfweg pumping station, where 40 to 80 per cent of the glass eels manage to get through. But sadly, at most of the sh passages, we have seen only a low success rate, sometimes of only a few per cent.’
SOLVING BOTTLENECKS
Recent ndings by various researchers will be published at the end of 2024 in a national glass eel barrier list providing information about over 100 locations, says Gri oen. ‘This will provide water management organizations with more insight into the state of a airs and where much can be gained by taking measures.’ The key thing now, the researcher explains, is to solve the bottlenecks for incoming glass eels, while not neglecting eels at other stages in the life cycle, like the resident yellow eels and the departing silver eels, says the researcher.
Glass eels are marked with a specific colour indicating the location and time, which allows scientists to work out where they face obstacles.
PHOTOS
So it is bad news that the deadliest pumping station in the Netherlands is located precisely at the big lock in IJmuiden, says Gri oen. ‘Silver eels often choose the route with the most water discharge. At IJmuiden, that often means swimming out to sea through the pumping station. We have calculated that 10 to 15 per cent of all the departing silver eels die, which is a terrible shame,’ he says. You can take measures such as adapting the way the pump is managed or scaring the eels o with noise or strobe lights, but these are just sticking plasters, says the researcher. ‘The solution really lies in installing sh-friendly pumps which a silver eel can and does swim through without coming to any harm. But it will take a while before every pumping station in the country has a pump like that. Pumps last a long time, and do not usually get replaced before their time is up.’
LAYER OF SLIME
Meanwhile, Palstra and Heinsbroek are working not just on breeding the larvae, but also on nurturing the eels from the glass eel stage to adulthood. ‘From the glass eels we breed beautiful silver eels with a good layer of slime, no sign of stress or aggression, by simulating the trip to the Sargasso Sea in arti cial channels,’ says Palstra. The eels swim against the current. ‘A propellor creates a current moving at 0.57 metres per second, with which we get them to swim 3000 kilometres – on the spot, of course. That su ces to turn them into maturing silver eels.’ After a year and a half, the researchers can already use these eels as parent sh, and stimulate further maturation using hormones. ‘So we don’t have to wait between seven and over 50 years, the time it takes for wild eels to mature.’
It would be nice if the sh could decide for themselves when to ovulate and spawn, says Palstra. He is working with Finnish researchers and the Maretarium, a saltwater sh aquarium in Kotka, Finland, where a 43-year-old female eel spontaneously matured to the spawning stage. ‘She was one of a group of eels of over a metre long, which are monitored continuously. The knowledge gained like this is of great importance because we don’t have any information about spawning eels in the Sargasso Sea. Naturally matured European eels have never been caught, neither in the Sargasso Sea nor elsewhere.’ W
www.wur.eu/eel
‘The solution lies in sh-friendly pumps’
BEN GRIFFIOEN
PhD researcher in the Aquaculture and Fisheries chair group, Wageningen Marine Research
COUNTING SILVER EELS WITH AI
To find out how many adult silver eels depart from the fresh inland waters to the Sargasso Sea to spawn, professional fishers collaborating with Wageningen Marine Research catch the eels in their traps. They can soon see whether they’ve caught a yellow eel or a silver eel. A silver eel is longer, with a silvery belly and a dark back: the perfect camouflage for the long journey. It also has large eyes with a blue tint, enabling it to see better in deeper water.
Researchers get both yellow and silver eels to swim past underwater cameras in IJmuiden. ‘The artificial intelligence software behind the camera teaches it to distinguish between the different eel stages,’ says freshwater ecologist Jorn School. ‘If the eye-to-length ratio is smaller, it is a yellow eel, and otherwise it is a silver eel.’ School hopes this will enable researchers to estimate more accurately how many silver eels embark on the journey. ‘A big advantage is that the eel can continue on its way and isn’t stuck in a trap for days.’ The camera also records the exact time of detection, enabling the researcher to analyse how migration behaviour is influenced by conditions such as the phase of the moon, the temperature or the current.
PHOTO BRAM BELLONI
Removing medicine residues from water
TEXT RENÉ DIDDE ILLUSTRATION SHUTTERSTOCK
People are getting older, which has led to increasing use of medication. And that’s a problem for water quality.
Residues of medicines and contraceptives such as the pill get into the sewage via urine and then slip through the conventional sewage puri cation systems. Every year, more than 190 thousand kilograms of drugs end
A new Wageningen water purification technique, developed in part by Royal Haskoning DHV, removes up to 90 per cent of medicine residues from sewage. Microorganisms and ozone are used to get the job done. The first system is currently being built in Zeist.
up in the surface waters, according to the National Institute for Public Health and the Environment (RIVM).
Drinking water companies that use surface water are nding it ever more di cult to remove these substances from the water.
Many of them are also harmful to aquatic life. The widely used painkiller diclofenac,
for example, can harm the gills, liver and kidneys of sh. It is known that the contraceptive pill can cause sex changes in sh and that antidepressants in uence the behaviour of sh and crabs.
Water authorities have been working for years to remove these persistent substances from sewage using new techniques and
‘Biological methods do most of the dirty work’
extra puri cation steps. One of the methods involves adsorption of drug residues onto activated charcoal – a type of Norit – while another method breaks the contaminants down into less harmful, smaller molecules using ozone. For a while, technologists were also investigating ultraviolet light for breaking the compounds into smaller pieces, but that costs too much energy.
About ten years ago, a Wageningen research team of PhD candidates, led by professor of the Environment and Water Technology Huub Rijnaarts, started developing a new puri cation technique. In this new method, microorganisms that can adhere to activated carbon as a kind of bio lm take care of the most easily degradable parts of the drug residues, explains alumnus Arnoud de Wilt. He worked in Wageningen as a PhD candidate on the development of the technique and has since been working for several years for the consultancy Royal HaskoningDHV. ‘We saw that after a while, a whole zoo of microorganisms were nestled in the bio lm. At rst, we gave these organisms plenty of time to clean up most of the mess.’ The scientists had to make sure that the organisms got enough oxygen, otherwise they didn’t do much with the drug residues.
OZONE
The researchers then transferred the remaining, hard-to-degrade part to a small tank that they added ozone to. This highly reactive ‘super-oxygen’ breaks down the contaminants by cutting molecular chains to pieces. The widely used epilepsy drug carbamazepine, for example, remained intact despite the breakdown attempts by the army of microorganisms. ‘But it does get broken down by chemical oxidation in the ozone reactor. Because most of the dirty work has already been done using biological methods, only 25 per cent of the usual amount of ozone is needed,’ says De Wilt.
That doesn’t just save on costs. ‘The more limited dose of ozone creates little to no bromate, a harmful by-product of the ozone reaction,’ says De Wilt. ‘Bromate is a potentially carcinogenic substance when consumed by humans, but it poses no danger to the aquatic environment.’ The energy requirements are also a lot lower.
ENGINEERING PRIZE
Using biological processes in water purication is a typical Wageningen approach. The technique, dubbed Aurea, won ‘De Vernufteling’ in May of this year, a prize awarded by engineering associations Koninklijke NLIngenieurs and KIVI and engineering magazine De Ingenieur for innovative engineering projects with social added value.
The new approach renders up to 90 per cent of pharmaceutical substances harmless. Now it has to prove itself in practice. Currently, the regional water authority De Stichtse Rijnlanden is building a fullyedged system at the sewage treatment plant in Zeist. Recent comparative research has shown that multiple new puri cation techniques are now ready for implementation. ‘Our technique is scoring really well,’ says De Wilt. ‘A second full-scale project will follow this year.’ Not all the 314 wastewater puri cation plants in the Netherlands will opt to use the Wageningen technique. ‘I expect a market share of 20 to 40 per cent.’ Aurea cannot clean up the current problem substance PFAS, research shows. De Wilt: ‘I do see opportunities to use this technique as a puri cation step for removing as much junk from the water possible, after which a PFAS breakdown technology can tackle the rest more e ciently.’ The Environmental Technology chair group is working on a PFAS destruction technology, in collaboration with Royal HaskoningDHV and other partners. W
www.wur.eu/purifying-wastewater
PURIFYING WATER AT SOURCE
In Wageningen Food and Biobased Research is also researching purifying wastewater at source, such as in medical care centres, in collaboration with hospitals, water authorities and technology suppliers. ‘Removing pharmaceutical and antimicrobial resistant substances on site is more effective than through purification at water treatment plants,’ says project leader Tania Mutiba Zambrano. ‘We first analyse the chemical and microbiological components in the wastewater, and assess various techniques for removing these substances. There are already a lot of state-of-the-art techniques in this area, but no single technique is enough. We need to combine different techniques. This makes the process more efficient and reduces the energy consumption. The first half of the study consists of tests in the lab. In early 2025, we’ll analyse the effectiveness of the technology in several hospitals or care institutions.’
AUTONOMOUS GREENHOUSE CHALLENGE:
Whose software grows the best tomatoes?
In the greenhouses in Bleiswijk, five international teams are competing for the title ‘best autonomous grower’. The biggest challenge in this two-yearly competition is that the participants are not allowed into the greenhouse. The software that makes the decisions about the growing conditions is developed beforehand by the teams.
TEXT TANJA SPEEK PHOTOGRAPHY STUDIO SARAH VLEKKE
Standing in the Wageningen Plant Research greenhouse in Bleiswijk are three long metal tables, lled with dwarf tomato plants in pots. The rst green tomatoes are hanging low down on the plants, and higher up there are still yellow owers. Pollinating bumble bees y from ower to ower from their cardboard nest. Each plant has its own drip-feeder to provide it with moisture. Higher up in the greenhouse, the LED lamps have just been come on. Above the middle table hangs a modest camera in a square grey casing, not recognizable if you don’t know what it is. In the next greenhouse compartment stand similar installations with dwarf tomatoes. This is where the Autonomous Greenhouse Challenge is taking place.
Five teams are each responsible for one compartment. The big challenge in this competi-
tion is that the participants are not allowed into the greenhouse. In fact, once the nal phase is underway, the teams are not allowed to change anything about the AI software they programmed in advance. Decisions about the circumstances under which the ventilation kicks in, when the lights go on, when extra heat is needed, or when to give the plants CO2 or water, have already been made. The winner is the team that nds the best balance between the yield and the costs.
DEVELOPING SOFTWARE
‘The competition started earlier this year with online assignments for all 20 registered teams,’ explains Stef Maree, the organizer of the Greenhouse Challenge on behalf of Wageningen Plant Research. ‘In a crop simulator, a digital model that simulates crop growth under di erent circumstances, the
teams could experiment with a wide variety of settings, to get some practice and to show their understanding of the issues.’ This was followed by a hackathon in the Netherlands in June. Now it was up to the image experts from the teams to roll up their sleeves and tackle a new part of the challenge: biological pest control. ‘In every greenhouse, there’s a sticky yellow board which pest insects get stuck to. The automatized system takes a photo of it every day,’ says Maree. ‘During the hackathon, the teams had to develop recognition software for this, based on a few photos.’ Finally, a jury picked the ve teams that had performed best on these assignments, and they went through to the nal round, in which they got to manage their own greenhouse compartment from September. The period between June and September was the busi-
est for the teams, as they had to build the AI models with which they would control the greenhouse until mid-December. The algorithms they developed then would do all the decision-making.
FIRST TIME
KwangSup Lyu from South Korea is the captain of Team Trigger. He is CEO of Grit, an IT startup that is a subsidiary of the high-tech greenhouse construction and supply company Daeyoung. His team is taking part for the rst time, and made it to the nal round, says Lyu on a video call. ‘We previously took part in a similar competition in South Korea, and won.’ His team is made up of some of his immediate colleagues as well as an AI expert, a student and a crop consultant from Korea. It is an unsettling experience, Lyu says, not to be able to walk through the greenhouse
‘It’s a challenge to use all those sensors correctly’
yourself. He would prefer to see the plants from close up. ‘Now all we have are the live images taken from above. I can’t see the colour of the stems or whether the owers low down on the plant are already growing into tomatoes. Of course, with the camera images we measure a lot of other data, such as the leaf surface, but it does feel di erent.’ High-tech greenhouse horticulture is still
quite a new thing in South Korea, explains Lyu. ‘So there is a lot to learn. In total, our country has about 57,000 hectares of greenhouses. Most of them are just plastic tunnels, and there are only 500 hectares of modern glasshouses. But the government supports growth in that sector, and we are on the brink of major changes.’
Other nalists include teams from China, Delft University of Technology in the Netherlands, and another South Korean team. WUR has a team too. It’s called Tomatonuts and is led by PhD candidate Ziye Zhu, who is taking part for the second time. Most of the members of this team are his colleagues in the Agricultural Biosystems Engineering chair group, while a few are researchers from the Horticulture and Plant Physiology group. ‘And an experienced manager at the greenhouse complex in Wageningen is involved. I’m do-
The greenhouses with baby tomatoes in Bleiswijjk are fitted with cameras and sensors that provide data for the AI software that controls the greenhouse.
‘At rst, I checked the gures on the website every hour’
ing this alongside my PhD research, but I hope to be able to use it in my thesis about autonomous greenhouse control,’ says Zhu. Bart van Laatum, a fellow PhD researcher in the chair group with an IT background, is participating for the rst time. ‘It’s educational, but intensive. Many of the hours we put in were in our own time.’
EVERYONE CAN LOOK
All the teams can be followed online on a dashboard with all the data on the tomato plants. In the canteen in Bleiswijk there is a large touchscreen on which the dashboard is visible all day, so you can see all the main parameters for the plant growth for every team. Temperature, humidity, watering, lighting and the average daily costs, for example for energy and greenhouse rent. There are also live camera images from every greenhouse compartment. Maree explains that the screen keeps the sta in Bleiswijk interested in the challenge. ‘Everyone has a quick look: how is it going? And we chat about it.’ Just like the other teams, Team Tomatonuts follows the data avidly. Zhu: ‘When we rst
started on this part of the challenge, I was looking at the gures on the website every hour. Would the parameters respond the way we expected? To start with, our plants grew more slowly than other teams’ plants.’ Van Laatum adds: ‘And we also look at what the other teams do. We can’t see what they have programmed, but we do get an impression of their approach. One team, for example, keeps the lights on nearly all the time.’
SELF-DEVELOPED SENSORS
Above one of the teams’ tables in the greenhouse, there are four seemingly randomly rotating black balls of cameras. ‘In simple terms, they estimate the photosynthesis activity in the plants,’ explains Maree. This is an example of the self-developed sensors that the teams are allowed to add. They are often sponsored by companies who want to get some experience with their latest gadgets. Team Tomatonuts is sticking to the basic sensors. Van Laatum: ‘It’s enough of a challenge to program all those sensors optimally and to understand them. There is a sensor for soil humidity, for instance, which can
help you give the right amount of water. But we didn’t understand the sensor well enough. We decided just to observe the data from it and not to use it in our algorithm.’
EXPERT GROWERS
A fully automatized greenhouse without any sta sounds like rather a sterile future. But that isn’t the goal, says Maree. ‘This technology can support a horticulturalist. But of course good growers want to walk through their greenhouses to see how their crops are doing. The sta ng shortage in greenhouse horticulture is getting even worse at the moment, while the sector is growing and companies are getting bigger.’
Good algorithms can support growers so that they don’t have to monitor everything themselves. In practice, Maree expects that it will be a case of making daily adjustments based on the information from the measurements and their own knowledge. ‘What is more, complicated decisions, about variable electricity prices for instance, can be done automatically, so that the grower can focus on the plants.’
Things are di erent in China, says Zhu. ‘There, we are good at building greenhouses now but we lag behind in knowledge about managing them. An expert grower is better than an algorithm, but an algorithm is better than a grower with limited knowledge and experience.’
The competition is all about nding the team that achieves the best balance among the weight of the plants – to be sold as pot plants –, the quality of the tomatoes, and the costs. ‘The nal deadline for the period in the greenhouse is 15 December, but we think some of the teams will harvest their tomatoes earlier than that,’ says Maree. ‘We will harvest for them.’ The costs of developing and running the software have not yet been integrated into the calculations. ‘That’s an important point, but it’s di cult to include. The electricity costs of AI can be high, but the development costs are the highest. But they go down per plant the more you can use the software. Maybe a nice addition for the next challenge.’ W
www.wur.eu/greenhouse-challenge
MUGROW
MORE AND MORE AUTONOMOUS
Since 2018, the Autonomous Greenhouse Challenge has been organized by Wageningen University & Research with the support of sponsors such as Tencent, an Asian technology company. A different crop is grown each time. In previous editions, the crops have been cucumbers, cherry tomatoes and lettuce. With each edition, the challenge gets one step further towards completely autonomous horticulture. In the first edition, the focus lay mainly on managing crop growth from a distance, and the teams were still allowed to ask greenhouse staff to do things like raise the temperature a bit.
A number of startups have sprung from previous challenge. Examples include Blue Radix in Rotterdam, and the American startup Koidra, which won the first and third challenges – the latter with a 30 per cent higher yield than the growers from the reference greenhouse. From South Korea, Croft is participating again, having won the preliminary rounds last year. These companies use AI and algorithms to help horticulturalists grow their crops more autonomously.
Five teams track the outcomes for their greenhouse compartment and the reference greenhouse via an online dashboard with live camera images and parameters such as temperature, humidity, watering, lighting and average costs.
TOMATONUTS
TRIGGER
Insuring crops through photos
For small farmers in remote areas it can be hard to prove they have experienced crop damage to an insurance company. A new insurance system in which farmers take photos of their crops with their smartphones offers them more security.
TEXT
PAULINE VAN SCHAYK PHOTO WUR
Afarmer in Kenya with a small plot of land faces complex decisions during the growing season. Should I start planting on the same day as I do every year? Will the rain come in time for the crops to grow well? Unforeseen weather circumstances increase the risk of signi cant loss of harvest and therefore of income. In the future, this farmer can better manage the risk of drought or other weather events with a new form of insurance. Any damage is documented in photos farmers take of their elds every couple of weeks. These help insurers assess the damage. Insurance against damage is di cult for small-scale farmers, explains Francesco Cecchi, associate professor in the Development Economics group. He conducts research in countries such as Kenya, Ethiopia and India, where millions of farmers farm on less than half a hectare of land each. ‘Most of those farmers are uninsured
because it is simply too expensive, and the chances of compensation are too small. The damage has to be veri ed in very remote areas, which is too much e ort for the insurer, so it doesn’t happen. Consequently, if there is any doubt about a claim, the farmer doesn’t get compensation.’
SATELLITE DATA
It was previously thought that the problem could be solved by using satellite data, making it easier to assess damage in remote regions. ‘Unfortunately, that didn’t increase the interest in insurance among small farmers. They still didn’t trust insurance companies to pay out in cases of damage. More rain might have fallen on one side of a hill than the other, and satellite data often can’t detect that.’ Being uninsured is a growing problem, as has been clear in recent years. ‘The risks of extreme weather are quite signi cant for farmers who depend on the yield of such a
small plot,’ Cecchi says. ‘They make annual risk assessments to maximize the chances of earning enough income for their families, and take precautions such as planting several di erent kinds of crop. Timing is crucial too. The ideal moment for planting is right before the rainy season begins, since these are usually crops that need every drop of rain. But with climate change, both the timing and the amount of rainfall are changing. This increases the risk that the crops won’t grow at all, with all the inevitable consequences of that. A failed harvest is catastrophic for people living on or just below the poverty line.’
DAMAGE EXPERTS
Working with the International Food Policy Research Institute (IFPRI), Cecchi has therefore developed a new method to provide proof for insurers in cases of yield loss: Picture-Based Insurance. Farmers use smart-
phones to take photos of their eld and upload them to the insurer. ‘The farmers must take the exact same photo of their eld every few weeks. If sudden damage occurs, you’ll see a clear di erence, and if there’s ongoing drought, for instance, you’ll see the damage increase gradually.’ When a claim is submitted, three damage experts review the photos. If they identify signi cant loss of harvest, the insurance company pays out.
In 2018, Cecchi and his colleagues launched a pilot in Kenya, Ethiopia and India in collaboration with the IFPRI and the national governments in these countries. Farmers were o ered free insurance: one group could try the new Picture-Based Insurance, and the other group received standard insurance. After three years, participants in the pilot could opt in to a paid version, priced the same as standard insurance. In Kenya, those who had experienced PictureBased Insurance were 30 per cent more
‘A failed harvest is catastrophic for people living on the poverty line’
likely to choose to purchase insurance. One of the farmers explained the main reason for choosing Picture-Based Insurance: ‘If misfortune strikes, I’ll have a much bigger chance of being compensated, avoiding losses and even making a small pro t, so I can farm again next season.’
ALGORITHM
The researchers are now training an algorithm with the photos collected so far. It will automatically assess how much damage the crops have su ered. In 88 per cent of cases, the judgement is in line with that of the ex-
perts reviewing the photos. Cecchi: ‘That’s a fairly high level of reliability, but not high enough to completely do away with human assessment. The advantage is that experts will only need to review the doubtful cases, which saves a lot of work.’ In the meantime, Cecchi hopes that insurance companies will make use of Picture-Based Insurance. One company is going to o er it, but in a more limited form. ‘In the end, it’s up to them whether and how they will integrate PictureBased Insurance into their products.’ W
www.wur.eu/pbinsurance
John Poi Namanjelie demonstrates the Picture-Based Insurance app on his farm in Bungoma, Kenya.
TRUFFLE GROWER JUDITH EVENAAR:
‘One decade later, this is still pioneering’
She wanted to spend more time outdoors and working on good nutrition. When she first encountered truffles at a conference, she was sold. So in 2013, Judith Evenaar plucked up courage and started a Dutch truffle orchard. ‘I can’t meet the demand.’
TEXT RIK NIJLAND PHOTOGRAPHY ERIC SCHOLTEN
‘Actually I was more of a cat person, but a tru le grower denitely needs a dog,’ says Judith Evenaar in her orchard on the Oranje Nassau Oord estate between Wageningen and Renkum. Although it isn’t the harvesting season, Turner gets to demonstrate how a tru le dog goes about its work, by way of training. Nose to the ground, she snu les around between the six-metre-tall hazel and oak trees as Evenaar encourages her with ‘Super, super!’, the way the dog’s German trainer did. When Turner carefully digs a shallow hole and lies down, Evenaar rushes over and shes what looks like a large, slightly mottled marble out of the sandy Veluwe soil. Bingo: a tru le. The dog has done a good job and is rewarded. Sadly, though, the haul is an undesirable in ltrator in the orchard. ‘There
are roughly 200 species of true tru les of the tuber family,’ explains Evenaar. ‘The culinary ones smell earthy and intoxicating, even heavenly sometimes; they give o a smell that has been described as that of a bed after a steamy night of lovemaking, a smell we savour.’ And the in ltrator? ‘It stinks. We’ve been nding more of them recently. I don’t know where this species comes from. Was it already present in the soil here, or did it arrive with the trees I have planted? Even after more than 10 years, this is still pioneering.’
A FOREST LOVER
Evenaar studied Food Process Engineering, which is a domain that leaves as little as possible to the vagaries of nature. She went on to work in the vaccination department at the National Institute for Public Health and
the Environment, RIVM, until she moved to Vancouver with her husband, who got a postdoc position there. ‘That’s where I discovered my passion for forests. I walked in the gorgeous Canadian countryside every day with the children. It was great. We seriously considered emigrating, but we missed our families, and we missed Wageningen. When we decided to come back to the Netherlands, we de nitely wanted to live here.’
She rst came to Wageningen from North Holland, as a student in 1983. ‘I’ve always had a passion for nutrition. I did Food Process Engineering because the way it drew on science subjects like physics and chemistry appealed to me, and in the course of my degree I developed an interest in microbiology as well.’
She enjoyed the vaccination research she
Judith Evenaar: ‘The culinary truffles smell earthy and intoxicating.’
did at the RIVM, which was a good t with her degree, but when she came back to the Netherlands, she decided to change direction. She wanted to spend less time at her computer and more time outdoors, with more of an emphasis on good nutrition. ‘I like small-scale local production, by people who are passionate about their work, and I like short supply chains that keep producers close to consumers.’
FORAGING
In 2002, she set up the Slow Food group Oogsten Zonder Zaaien (harvesting without sowing) specializing in foraging for edible plants and mushrooms in the wild. She and a colleague then developed a company called
Casa Foresta, running courses on foraging and providing packs for cultivated shiitake and king oyster mushrooms. Until she attended a mushroom conference in Morocco in 2011. ‘That’s when I rst encountered tru les. I was fascinated by them! Take the desert tru le, for instance: a fungus that lives in symbiosis with the rock rose. A delicacy which people pay a fortune for in the Middle East.’
‘Morocco is a country with a tru le culture and tru le orchards,’ Evenaar explains. ‘I knew nothing about tru les, not even that they could be cultivated. It’s a totally di erent ballgame to shiitakes and oyster mushrooms, the species that break down wood. Growing those is a nice production process too, but
fairly straightforward: you don’t need much more than some good wood and the right temperature and humidity. Tru les are more mysterious. They grow underground and they are mycorrhiza fungi that live symbiotically with trees and shrubs. That cooperation and the fact that they grow outdoors in nature still appeal to me tremendously.’
Evenaar shows me some microscopic lms of tree roots that are surrounded by a thin, downy layer of fungus. Both the tree and the fungus bene t from this symbiosis. The tree gets help with absorbing water and nutrients; in exchange, it provides its partner with sugars. In order to reproduce, the fungus forms fruiting bodies underground, which give o a strong odour and are tracked down by hungry creatures such as wild boar or squirrels, who then spread the spores via their droppings.
Or the tru les end up in the shoulder bags of old men in Italy or France, who sell their yields. That is still a major supply line, but according to Evenaar, a lot of tru les also come from countries that are less renowned for their tru le culture, such as Spain. And now at least half are from tru le orchards in Hungary, Morocco, Germany, China and, above all, Australia.
300 SAPLINGS
In 2013, Evenaar took the plunge and leased the overgrown former tree nursery of 0.8 hectares at Oranje Nassau’s Oord. Here she planted 300 knee-high saplings: intermittent rows of hazels, summer oaks, and – in anticipation of climate change – the heatloving downy oak and holly oak. Tru les can cohabit with several di erent tree species, sometimes even with r trees. ‘Contrary to popular belief, the oak is not the only possible host. It is crucial that the soil contains enough calcium,’ says Evenaar. ‘Here on the Veluwe, the soil was extremely acidic so we started by mixing in a lot of marl from Limburg to get a higher pH.’ She
opted for the bianchetti, or spring tru le. ‘Not much was known about how to grow it, so I was making life di cult for myself, but this species is occasionally found in the wild in the Netherlands, so it is not an exotic species.’ To establish the species in her orchard, she bought young hazels and oaks from specialized nurseries in Italy, Spain and the UK, where the roots are inoculated with fungal threads from the tru le, a method developed in 1970 by the French research
‘I think I’ve become a bit of a tru le junkie’
institute INRA.
She received advice during those early stages from Thom Kuijper of WUR, now emeritus professor of Soil Biology and a specialist on mycorrhizal fungi. She also looked at how other people were going about it, in her growing network of colleagues in countries from Finland to Morocco. ‘I don’t actually have much contact with the university. When I started, there wasn’t much interest in soil life and the tru le was seen as something exotic. That has changed since then.’
TRUFFLE DOG
Evenaar harvested her rst tru les in 2020. ‘I didn’t have Turner yet then. I had help from Fredo, a trained tru le dog whose owner had read about my initiative and approached me.’
In the years that followed, production went up to about 1000 tru les in 2023. ‘Most of
them were small though. But in 2024 I didn’t have as many, maybe because of the mild autumn and the extremely wet spring we had.’ Marketing the tru les is no problem at all, she adds. ‘I can’t meet the demand. Three restaurants in the area, one of them Hotel De Wereld, are regular customers. It’s wonderful to deliver your product to a chef who will then make something delicious with it.’ Alongside her own tru le production, Evenaar advises a dozen other Dutch tru le farmers who are following in her footsteps. ‘The biggest one is Tru ère Eyserhalte in Limburg, with 760 trees for commercial production of the summer tru le. But there are also farmers with only 20 trees or with a tru le hedge, who are just doing it for the fun of it.’
She also leads excursions to tru le farms in Hungary and guided tours and tastings in her own tru le orchard in Wageningen.
TRUFFLE CHOCOLATES
To round o the tour, Judith Evenaar has placed a couple of chairs and a table with a primus stove and a percolator between the trees. She serves co ee with homemade tru le chocolates, ‘my own speciality’, brie with tru le, and cauli ower soup, also with tru les in it. ‘I think I have become a bit of a tru le junkie – I think they’re delicious but I fell for the people involved even more: the tru le-hunters, the farmers and the researchers who try to discover the secrets of this mysterious fungus.’ ‘And then I also really enjoy acquiring knowledge and sharing it. If I hadn’t just given it a go over 10 years ago, I would have missed out on all of that. But of course, what I’m doing is a business too. Luckily there are more and more consumers who are willing to pay for an unusual local product. But I don’t measure success only by the return on investment; as you do in agroforestry, I cherish the birds and insects in my orchard. And this gorgeous workplace in the woods.’ W
JUDITH EVENAAR (59)
2013: Started truffle orchard, first harvest in 2020
2004-2010: Casa Foresta, foraging and growing mushrooms
2002: Founded Slow Food group Oogsten Zonder Zaaien
1989-1993: Vaccine researcher at RIVM
1989: Bioprocess Engineering WUR
TURNER
(4)
Cross between a Tervuren shepherd and a Labrador, trained by trufflegrowing experts from Deutsche Trüffelbäume.
‘WURth-while felt like a gift’
Refugees who are waiting for a residence permit in the Netherlands cannot yet sign up for a full degree programme at a university. The WURth-while programme offers them the chance to take courses at Wageningen University & Research.
TEXT PAULINE VAN SCHAYK
PHOTO BRAM BELLONI
‘After a year of waiting, I could work towards the future again’
‘It’s a long time to wait,’ says an African student (who wishes to remain anonymous). He left his home country in January 2023 and applied for asylum in the Netherlands. During the asylum procedure, which is still ongoing, he has moved several times between asylum seekers’ centres. ‘I was eager to have something to do, and what I wanted most was to continue my studies.’ In Africa he had been studying Agricultural Sciences, and he was active in the ght for a fairer and more sustainable world and against climate change. ‘Those activities led to it becoming unsafe for me to stay there. In the end I had to give up my studies and I left my country.’ In the Netherlands, he got in touch with the refugee organization VluchtelingenWerk Nederland, and found out about the Wageningen initiative WURthwhile, which o ers refugees the opportunity to take courses at Wageningen University & Research free of charge. ‘I signed up straightaway and I took two courses last spring that aligned with my interests in the climate and agriculture. After a year of waiting, I could work towards the future again.’
FUTURE PROSPECTS
The WURth-while programme was set up ve years ago by a few Wageningen teachers and VluchtelingenWerk Nederland to o er refugees who had to give up their studies in their home countries some future prospects and the chance to continue their education. If they are still waiting for a residence permit, they are not allowed to register for a regular Bachelor’s of Master’s degree programme at a Dutch university. University Fund Wageningen supports the WURthwhile initiative thanks to contributions from many donors, and covers the refugees’ travel costs and the costs of the course material. To date, 300 students have taken one or more courses through the programme, whether on campus or online.
Ahmed Agwa from Egypt, who lives in Amsterdam, took an online WUR course in
July on nutrition, cancer and cardiovascular disease. That was relevant to his professional background. He had quali ed as a doctor in Egypt and was working there as a GP. Taking the course gave him a chance to be productively active, he says. ‘And I could get a glimpse of what it would be like if I later decided to do a Master’s in Wageningen.’
BUDDY
Most WURth-while students come to Wageningen to take their courses. Valerie Knöpker, a student of International Development Studies, works for the programme as a student assistant. She evaluates applications and maintains contact with the teachers. ‘They are usually more than willing to admit these students to their courses. As teachers, they see the value for the refugees of being able to study while they wait for a residence permit.’
The WURth-while programme pairs up all the students with a buddy to keep them company and help them nd their way around the university. Knöpker became a buddy herself a year ago. ‘For some time I had wanted to contribute to the integration of refugees in the Netherlands, so when I saw an appeal for buddies on Facebook, I decided to sign up.’ During the rst few weeks, the support consisted mainly of practical matters: creating accounts, explaining the digital education systems,
SUPPORT FOR WURTH-WHILE
and giving guided tours of the campus. But she enjoyed the weeks that followed the most. ‘I met students with di erent experiences to what I’d had. It was great to talk about that. I am still in touch with the students I was buddy to. They’ve become friends.’
GROUP WORK
For both Agwa and the African student, the way education is organized at WUR took a bit of getting used to. ‘I found that almost everything was done digitally: from registration to using the course materials and submitting assignments,’ says the African student. ‘That was quite di cult at rst, but the course coordinators and my buddy always supported me. What I like is that students here do more group work.’ He hopes to continue his studies at Wageningen University in the future. Meanwhile, in Amsterdam, Agwa has started on one of the three online Master’s programmes that WUR o ers: Nutritional Epidemiology and Public Health. ‘WURthwhile felt like a gift. I thought it would be very di cult to do a Master’s in the Netherlands. This programme gave me the chance to make a well-informed decision to enrol for a Master’s programme in Wageningen.’ W
www.wur.eu/wurth-while
WURth-while is a project run by Wageningen University & Research and refugee support organization VluchtelingenWerk Nederland, offering student refugees the chance to take part in courses at the university, free of charge. Students are eligible if they have obtained a BSc degree or had made adequate progress towards one and also have a good command of English. University Fund Wageningen supports the project financially. The Fund is able to do that thanks to the contribution of many donors, the Friends of University Fund Wageningen, who support talent development within WUR. More information at: www.universityfundwageningen.eu/wurthwhile
SHARING KNOWLEDGE
Alumni contribute to research and education
Many Wageningen projects could make good use of the knowledge and experience of alumni, and graduates are only too pleased to help Wageningen University & Research with their expertise. In November, Wageningen’s Alumni Relations department launched a platform for linking alumni to projects.
The platform is a bit like a job vacancies site, says Maarten van Schaik, head of Alumni Relations. ‘It has various projects, each with its own search pro le such as prior education and eld of interest. Alumni who are interested can then register as potential participants in the project via the platform.’ Around ten projects a year are expected to be on o er.
As a kind of pilot, the Alumni Relations department looked for alumni for various Wageningen projects during the past year. They included I-CHANGE, a WUR citizen science project on heat in cities. ‘A lot of alumni said they were willing to make time for WUR, to share their knowledge and experience,’ says Van Schaik. ‘We can use that because plenty of Wageningen researchers are looking for people who can assist with citizen science projects or help develop courses for professionals.’ Femke de Kock studied Metropolitan
CULTURAL HERITAGE
Analysis, Design & Engineering in Wageningen and was one of the alumni who responded to the call to take part in I-CHANGE. Now she has two measuring stations installed in her Amsterdam at. De Kock: ‘I was keen to help out with the research and I was also curious about the measurements for my own apartment. I researched heat stress in Amsterdam homes for my Master’s thesis, so I already
Aula has become cinema Visum Mundi
The Aula is a historic site for many former WUR students and employees. More than 800 inaugurations and 8000 PhD defences have taken place there, in the heart of Wageningen, since 1935, and 50,000 degree certi cates handed out. Many ceremonies were accompanied by the distinctive sounds of its organ. The Aula closed in 2022, and the building reopened in September 2024 as the cinema Visum Mundi. The organ can now be heard in the San Pietro Apostolo church in Fiano, Italy.
Info: www.visummundi.nl
had a connection with the topic.’
De Kock is pleased with her involvement in I-CHANGE, she says. ‘The communication with the research team is good, they don’t make big demands on me and I have permanent access to the measurements in my at. Hopefully, the results will be used to develop appropriate measures for reducing heat problems in Amsterdam.’
Info: www.wur.eu/alu-engagement
Alumni survey
In the National Alumni Survey, universities ask recent graduates about the t between their Master’s programmes and the labour market. Alumni who graduated between October 2022 and September 2023 will have received an invitation to take part in the survey. ‘There’s always a high response rate among WUR alumni,’ says Silvia Blok, Education and Labour Market policy o cer. ‘That’s important because we use the results to improve the quality of our teaching.’ Info: www.nae2024.nl, silvia.blok@wur.nl
Support for young entrepreneurs
At the end of August, Wageningen University & Research and University Fund Wageningen launched the Wageningen Impact Catalyst programme. This programme assists young entrepreneurs in the early stages of their business with funding, coaching and strategic supervision.
Entrepreneurs who are just starting out often nd it di cult to get nancial support, says the University Fund director Lies Boelrijk. ‘It’s hard to get a loan or get investors interested at the ideas stage. That is why a lot of innovative ideas don’t
make it.’ University Fund Wageningen wants the new programme to double the number of entrepreneurial initiatives from Wageningen, such as start-ups, spin-o s and NGOs, over the next ve years. In addition to nancing, Wageningen Impact Catalyst also o ers expertise, emphasizes Boelrijk: ‘We’re trying to persuade alumni with experience in business, and other relations, to devote time to coaching the entrepreneurs, for example as a mentor or in a jury. That lets us give more time and attention to the preincubation phase of budding businesses in various ways.’
In April 2024, the Dutch Animal Science Association (NZV) started awarding scholarships to students and alumni aged under 35 who graduated in the past 10 years with an animal sciences degree. Each year, the society will be awarding ve scholarships of 1500 euros
for activities that further the aims of NZV: sharing information, exchanging knowledge and broadening horizons on topical subjects in the domain of humans, animals and the environment.
Info: www.nzvnet.nl/en/
Alumnus creates oak processionary caterpillar lm
Nature lm maker Je rey van Houten (BSc Forest and Nature Conservation 2018) is working on a lm about the oak processionary caterpillar with the help of the KLV Fund. While studying for his degree, Van Houten helped out with a lm about the Veluwe wildlife. After getting his Bachelor’s, he decided to work full time on lming and photographing nature. The lm is expected to appear mid-2025.
Info: www.universityfundwageningen.eu/klvfund
Wageningen alumni form a worldwide network of more than 68,000 Bachelor’s, Master’s and PhD graduates. There are various ways to keep in touch:
LinkedIn
The LinkedIn group Alumni @ Wageningen University & Research shares information about activities, job vacancies and interviews with former students. For example, you can read the interview with Saminathan Sivaprakasham Murugesan from India who set up the Safe Space Initiative in Wageningen.
Website
A seminar on development cooperation, an alumni event in Berlin or a reunion with former students who started their degree in 1974 – the WUR alumni website lists a wide range of activities for alumni in the Netherlands and abroad. www.wur.eu/alumni
Networks
The alumni community includes 14 independent study circles and networks, such as the Network for Wageningen University Alumni Women. It is for female alumni in the domains of food and agricultural sciences. www.wur.eu/studycircles
Newsletter
The alumni newsletter keeps graduates informed about developments at Wageningen, plus activities and stories. To subscribe, go to www.wur.eu/alumninewsletter
Moved or new job?
Go to www.wur.eu/changecontactinfo to notify us of any changes.
PHOTO JEFFREY VAN HOUTEN
Prof. Ruud Bartholomeus, Hydrology & Water Quality 2005, has been appointed professor by special appointment in Plant Water Stress & Regional Water Management in the Soil Physics and Land Management chair group. 29 August 2024.
Prof. Robert Biesbroek, Landscape Architecture & Planning 2007, has been appointed professor of Public Governance & Climate Change Adaptation. 29 May 2024.
Mario Calus PhD, Zootechnics 2001, has been appointed professor of Animal Breeding & Genomics. 28 May 2024.
Aalt Dijkhuizen PhD, Agrarian Economics 1977, former President of the Executive Board of WUR and co-director of Holland Center China, has become the Strategic Advisor for International Cooperation at the Inner Mongolian Agricultural University in China. June 2024.
Prof. Nick van Eekeren, Zootechnics 1990, researcher at the Louis Bolk Institute, has been appointed professor by special appointment of Regenerative Grassland Systems in the Farming Systems Ecology chair group. The professorship is co-funded by the Louis Bolk Institute and Triodos Foundation. 10 September 2024.
Prof. Thijs Ettema, Biology 2000, chair holder in Microbiology, received an ERC Advanced Grant of 2.5 million euros for research on the origins of complex life. 5 July 2024.
Stef de Haan PhD, Ecological Agriculture 1998, has been appointed professor holding an endowed chair in Seed Systems & Agrobiodiversity in the Biosystematics chair group. 2 September 2024.
Prof. Nynke Hofstra, Environmental Sciences 2005, has been appointed professor of Water Systems & Global Change. 1 August 2024.
Prof. Sander Koenraadt, Biology 1998, has been appointed professor holding a personal chair in Ecology and combating pathogenic insects at the Laboratory of Entomology. 4 June 2024.
Prof. Liesje Mommer, Biology 2000, professor of Belowground Ecology, received an ERC Advanced Grant of 2.5 million euros for research on the underground properties of plants such as root thickness and how they a ect disease pressure. 5 July 2024.
Jean Rummenie MSc, Horticulture 1982, has been appointed State Secretary of Fisheries, Food Security and Nature on behalf of the BoerBurgerBeweging political party in the Schoof cabinet. 2 July 2024.
Prof. Jantine Schuit, Domestic & Consumer Studies 1990, professor of Health, Behaviour & Society at Tilburg University, has been appointed rector magni cus at Erasmus University. 1 November 2024.
Prof. Bregje Wertheim, WUR PhD 2001, has been appointed professor of Entomology at the Laboratory of Entomology. She succeeds Prof. Marcel Dicke. 1 September 2024.
Prof. Hannah van Zanten, Animal Sciences 2009, has been appointed professor of Environmental Systems Analysis. 1 October 2024.
Prof. Marcel Zwietering, Molecular Sciences 1987, received the Frozen Food Foundation Freezing Research Award in Long Beach, USA, for his exceptional contributions to research on the food safety aspects of freezing. 19 July 2024.
Growing vegetables in containers in Ukraine
Jort Maarseveen MSc, Biobased Sciences 2024, and Tijmen Blok MSc, Aquaculture and Marine Resource Management 2024, have developed the Hippotainer: a vertical farm in a lorry container in which vegetables can be grown in ve layers.
Maarseveen: ‘We wanted a system that was easy to transport, and of course a container is ideal from that point of view. You can just load it on a truck. The system can also easily be put to use at the destination site as you
don’t need buildings or permits. That lets you make a real impact, especially in places where conventional forms of agriculture are tricky.’ Their rst container was installed in the war-torn city of Ivano-Frankivsk in Ukraine, where it has been producing hundreds of heads of lettuce a week since the summer of 2023. Blok and Maarseveen are working on taking the container to other parts of the world.
https://hippotainer.com
Film about ecotourism
Abel Chacón Hoekstra BSc, Economics & Policy 2024, shot a short lm about ecotourism in Costa Rica during his degree studies. The lm – Armonia ambiental, un retrato de la familia Mora (In harmony with the environment, a portrait of the Mora family) – follows a Costa Rican family business working on nature conservation. Chacón Hoekstra, who was born in the Netherlands but grew up in Costa Rica, spent ve days with the Mora family lming them. The lm was screened at the Schnit Short Film festival in San José, Costa Rica in October: ‘I saw my project on the big screen, with over 250 people in the audience. That felt like a great reward for all the hard work, and quite unreal.’ The lm can be viewed on Vimeo.
A wife for farmer John
Farmer John Nouwen MSc, Management, Economics & Consumer Studies 2013, is looking for a wife. The poultry farmer from Leuldal in Limburg is taking part in the Dutch TV show Farmer Wants a Wife 2024/2025. In the rst episode, which was broadcast on NPO 1 on 22 September, Nouwen and the other farmers presented themselves. Women who were interested could then write in, with a deadline of 6 October. Further episodes will follow in 2025.
IN MEMORIAM
Alumni and current and former employees of Wageningen University & Research who have recently passed away.
Mr H.F. van Ark MSc, Plant Breeding 1988. 25 July 2024.
Mr G.J. van den Berg MSc, Forestry 1972. 9 September 2024.
Mr J. Born MSc, Forestry 1960. 11 September 2024.
Mr W.G.C.M. van Dommelen MSc, Biology 1983. 21 September 2024.
Mr F. van Dorsten MSc, Rural Sociology of the NonWestern Regions 1981. 10 October 2024.
Mr J. Doorenbos MSc, Tropical Land Development 1963. 27 October 2024.
Mr A.F. Eshuis MSc, Food Technology 1970. 19 June 2024.
Mr J.A. Garritsen MSc, Food Technology 1988. 24 May 2024.
Mr N.J.A. ten Heggeler MSc, Soil, Water and Atmosphere 2001. 2 June 2024.
Mr J.H. Hellinga MSc, Phytopathology 1981. 22 October 2024.
Mr H.T.J. Hettinga MSc, Zootechnics 1984. 4 May 2024.
Ms M.J.C.L. Huydts MSc, Tropical Rural Economics 1963. 7 July 2024.
Mr A. Kannegieter MSc, Tropical Rural Economics 1954. 14 October 2024.
Mr O.A. van Keeken MSc, Zootechnics 2002. 29 April 2024.
Mr A. Keetman MSc, Landscape Architecture 1989. 7 June 2024.
Ms A. Kocherezhko BSc, Environmental Sciences 2024. 5 August 2024.
Mr N.C.A. Koomen MSc, Horticulture 1972. 14 July 2024.
Ms I.M. Kooter MSc, Molecular Sciences 1994. 26 March 2024.
Mr J.J. van Mourik Broekman MSc, Environmental Protection (Water Purification) 1980. 23 July 2024.
Mr J. Prins MSc, Rural Economics 1960. 9 April 2024.
Ms P. Reidsma PhD, WUR doctorate 2007. 2 June 2024.
Mr A.S. van Riessen MSc, Tropical Land Development 1982. 7 July 2024.
Mr J.H. de Ru PhD, Rural Sociology of the Western Regions 1966. 23 June 2024.
Mr H.J.F. Savenije MSc, Forestry 1981. 2 June 2024.
Mr R. Steensma MSc, Rural Economics 1967. 18 April 2024.
Mr J.P.H. Tendijck MSc, Plant Breeding 1988. 5 July 2024.
Mr P.J. Ton MSc, Forestry 1969. 1 June 2024.
Mr E. Top MSc, Zootechnics 1977. 24 June 2024.
Mr R.W. den Outer PhD, Forestry 1959. 2 May 2024.
Ms E.M. VaarkampZwart MSc, Tropical Land Development 1979. 15 September 2024.
Mr J. Veenstra PhD, Tropical Land Development 1966. 4 September 2024.
Mr M.M.C. Verkleij MSc, Land Development B 1981. 31 July 2024.
Prof. L.C. Zachariasse, Rural Economics, 1965. 18 July 2024.
If you would like to inform us of the death of a fellow former student or relative, you can email alumni@wur.nl or send a death announcement to the Alumni Department, Wageningen University & Research, Droevendaalsesteeg 4, 6708 PB Wageningen,The Netherlands.
Lizzy Grant for four start-ups
Wageningen Ambassador Peter Poortinga MSc, Agricultural Plant Breeding 1987, CEO of the Wageningen company Solynta, set up the Lizzy Grant to help young entrepreneurs grow their start-ups. On 28 August, he handed out grants of 5000 euros to four entrepreneurs who are just starting out:
Mendelt Tillema, former Plant Sciences student, received a grant for Zwamcijsje,
a savoury bread roll lled with fungi grown according to circular agriculture principles. Matthew Halley MSc, Urban Environmental Management 2024, and his start-up SoualiGas received a grant for his approach using thermochemical conversion to help small island states recycle waste. Alumnus Bart van Gorcum MSc, Management, Economics and Consumer Studies 2022, and his start-up
BOOKS BY ALUMNI AND WUR EMPLOYEES
The nitrogen web
How did we end up with the nitrogen crisis? In his book, Wageningen ecologist Wieger Wamelink PhD, Plant Breeding 1993, explains what too much nitrogen does to plants and ecosystems and how the consequences are seen in the nature around us. New Scientist, 14.99 euros
Kicking the bucket
Karin Anema MSc, Landscape Architecture 1980, investigates how people in di erent cultures deal with death. She introduces the reader to the colourful customs of the Dutch, Ghanaians, Mexicans and Surinamese Indians, among others. Scriptum, 22.50 euros
Rowing from the Rhone to the Rhine
When Josien Kapma MSc, Tropical Land Use 1996, reached a turning point in her life, she decided to take to the waters. She bought a one-person rowing and sailing boat in the Alps and sailed it 1200 kilometres back to the Netherlands. In her book she writes about the silence of a boat without an engine, the setbacks and the unusual encounters. Roei.nu, 24.50 euros
Rainwater Harvesting for the 21st Century
Rainwater collection is increasingly seen as an alternative water source and a form of climate adaptation. In this book, edited by Ilan Adler MSc, Environmental Engineering Technology 2001, more than 45 experts discuss the current state of research on rainwater harvesting with practical examples of pioneering innovations. Taylor & Francis, 101.77 euros
Valuesort.ai received a grant for image recognition software that helps identify valuable items of clothing and textiles, for example for vintage clothing stores. Alumnus Elisabeth Obeng MSc, WUR Economics & Governance 2018, and her start-up Afropulse received a grant for her work helping Ghanaian farmers to sell pulse products on the European market.
David and I
‘I can read thoughts and I want you to know that,’ says David to the main protagonist Pim in this autobiographical debut novel by Gijs van der Logt MSc, Soil, Water & Atmosphere 2005. In the book, he incorporates his experiences from his time at Wageningen University. Pim, the author’s alter ego, decides to test David’s claim. Paris Books, 23.99 euros
Laws for nature
‘Legislation, especially environmental legislation, is increasingly viewed as optional policy’, concludes former associate professor of Environmental Law Fred Kistenkas in this book, published on his retirement. The book contains 35 of his columns on law and policy in the domain of nature and the environment. Noordboek, 19.90 euros
The Resilient Society
‘Six years of my life went into this passion project,’ says Ivo Lammertink MSc, Economics, Environment & Governance 2018. The nal result is a book about his vision for the future of the planet. Lammertink gives his views on the pitfalls of capitalism and the path to a more sustainable society. New World Books, 18.28 euros
Epidemiology of Infectious Diseases
In this book, Jos Franzen PhD, doctorate 1994, takes a broad look at epidemics among humans using his knowledge of epidemics in plants and drawing on the social sciences and humanities. He invites students and colleagues to consider the subjective side of epidemics in the hope of inspiring more humane measures. Brill, 95.92 euros
Janse Heijn, magician
‘My hobby became my profession, and my subject became my hobby’
International Development Studies and Forest and Nature Management 2015
‘My fascination with magic started when I got a marvellous magic book from my grandpa. From then on, I spent all my pocket money on special packs of cards and coloured cloths.
‘When I was in my teens and still wanted to be a magician when I grew up, my parents said: first get a proper qualification. On an exchange programme with Brazilian youngsters, I was disturbed by the extreme poverty I was confronted with. So a degree in International Development Studies was an obvious choice.
‘Once I got to Wageningen I discovered the Forest and Nature Management programme as well. Nature conservation – and especially the conservation of tropical rainforests – held a strong appeal for me, so I decided to
do two Master’s degrees. Meanwhile, I continued to perform as a magician. While other students had side jobs as waiters or security staff, I performed my tricks every weekend at children’s parties and in restaurants.
‘When I graduated, jobs were scarce and I decided to become a professional magician. It’s a great job: it’s fun to entertain people from all the echelons of society. I perform at receptions, company parties and symposia.
‘Tropical forests still fascinate me. In 2022 I went back to Borneo, where I had done research as part of my degree programme. My friends and I have set up a small project to finance a water purification station. So my hobby has become my profession, and my degree subject my hobby.’
Cities are sinking due to groundwater extraction
What do Venice, Jakarta, Manilla and Bangkok have in common? They are or were all sinking cities. The main cause of the soil subsidence in these cities is groundwater extraction, says the Wageningen physical geographer Philip Minderhoud, who has been studying soil subsidence in the Mekong delta in Vietnam. ‘In recent years, we have been seeing an acceleration in the soil subsidence there, which has now reached about seven centimetres per year.’ Minderhoud is also involved in research around Manilla, in the Philippines. ‘There the
soil is subsiding by 10 to 12 centimetres per year. Part of the coastal area is already under water and villages have been swallowed up by the sea.’
Soil subsidence can be prevented or halted by reducing or ending groundwater extraction. The Japanese capital, Tokyo, sank four metres in the 20th century, but managed to curb the process by imposing strict groundwater management, constructing water reservoirs around the city and all but ending groundwater extraction. Bangkok, in Thailand, succeeded
in controlling soil subsidence in the same way. Research is needed so that we can spot and prevent soil subsidence in coastal regions in good time, thinks Minderhoud. ‘There’s massive population growth going on in cities along the West African coast. Ever more groundwater is being pumped up, and the first signs of soil subsidence are visible in a metropolis like Lagos. By documenting the causes and the solutions, we might be able to nip soil subsidence in the bud.’
