This yellow glyphosate map shows where farmers are spraying that controversial agricultural poison

This article is nominated for the European Press Prize 2025 in The Innovation Award category. Originally published by Follow The Money, The Netherlands.

This piece in 1 minute

What's the news?

• Every year, farmers spray some 42,000 hectares of land with glyphosate or similar herbicides. That's an area the size of five times Terschelling.
• Glyphosate is also used in 108 groundwater protection areas and near 96 protected Natura 2000 areas and 176 primary schools. 700 thousand Dutch people live within 250 metres of a sprayed field.

Why is this important?

• Glyphosate is harmful to biodiversity and possibly also to humans. Research is currently being conducted into the relationship between glyphosate and diseases such as cancer and Parkinson's disease.
• The RIVM recommended better monitoring of pesticide use back in 2019, but this has not been done so far. FTM is now literally mapping glyphosate use for the first time, together with seven regional media partners.

How did we research this?

• Fields sprayed with glyphosate turn a typical yellow colour. FTM used satellite photos from European space agency ESA and built an algorithm to detect this yellowing of fields.
• We combined this glyphosate map with maps of groundwater protection areas, nature reserves, maps of protected waters and with the locations of all primary schools and some thirty thousand playgrounds in the Netherlands.
• The full methodology of this research can be found at the bottom of the article.

Was this framework useful?

Every spring, part of the Dutch countryside suddenly turns yellow and orange. Farmers then spray their fields and meadows with glyphosate to clear them and sow new crops.

Glyphosate is the active ingredient in Roundup, the world's most popular weed killer , sold in a green bottle with a yellow cap. The drug generated sales of €1.3 billion for manufacturer Bayer in the first half of this year, 6 per cent of the company's total sales. Glyphosate is unrivalled in controlling weeds: it blocks the uptake of certain enzymes in plants, killing them.

But the drug is also controversial. It harms biodiversity and soil and water quality. There are also public health concerns. Glyphosate is associated with an increased risk of cancer and Parkinson's disease.

Roundup is also among the best-selling plant protection products in the Netherlands. Arable farmers are major users here: they account for 51 per cent of all Dutch glyphosate use, followed by dairy farmers (10 per cent) and bulb growers (7 per cent). Nine in ten arable farmers use the pesticide (sometimes). Among dairy farmers, it is about half.

That many Dutch fields and meadows turn yellow in spring because of glyphosate has long been known. But where and how much is sprayed and what the risks to the environment are, has so far been unclear. Consequently, the glyphosate debate is mainly conducted on the basis of anecdotal evidence.

On animal spotting website Waarneming.nl, people can report yellowed glyphosate fields under a separate category. Between 2020 and 2024, the number of annual (otherwise unverified) reports doubled. D66 in 2022 called for photos of those yellow fields not only to be uploaded there, but to be sent directly to the minister. Caroline van der Plas (BBB) characterised that plan as a ‘witch hunt’. Farmers' organisation LTO Nederland was slightly more diplomatic, advising its members to dig up the yellow glyphosate fields from now on to avoid “criticism from society”.

Following an adopted motion by D66, GroenLinks and Partij voor de Dieren, former agriculture minister Piet Adema promised a ban on the ‘spraying to death’ of fields by 2025. Adema's successor, Femke Wiersma (BBB), informs Follow the Money that she is currently considering whether to adopt Adema's ‘death spray’ ban. The Lower House will debate the issue on 27 November.

Five times Terschelling

The science is not yet clear on exactly where all the glyphosate sprayed on fields ends up. Back in 2019, the RIVM recommended mapping that out, followed by the Health Council in 2020. So far, those recommendations have not been followed.

But because of the striking yellow colour the pesticide causes, sprayed fields can be seen from space.

Using satellite images from the European Space Agency ESA, Follow the Money, together with seven regional media outlets, managed to get a single view of all yellow fields from the spring of 2020 - a relatively cloudless spring - in the Netherlands.

The research design allowed fields that turned yellow due to other causes (e.g. drought or ploughing) to be excluded.

Because glyphosate adheres well to soil particles, the stuff remains present in the environment for years - even if farmers have long since stopped spraying. Violette Geissen is a professor at Wageningen University & Research (WUR) and leads a European research project on the effects of pesticides on nature and public health. She says: ‘When glyphosate comes out of the sprayer, some is carried away with the wind. Most of that settles down within 250 metres. But then another gust of wind can carry it even further. In addition, glyphosate can bind to fine soil particles and house dust that can get everywhere via higher air layers.'

Spray ban on leased land

Since 2020, eight provinces have banned the spraying of glyphosate on land that farmers lease from the province at contract renewals. Of the fields that were sprayed in 2020, up to 5.2 per cent are now subject to a spraying ban, Follow the Money calculated. An unknown number of municipalities have also introduced spraying bans since then. A ban has also been in place on State Forestry Commission leased land for some time.

Last summer, then outgoing Minister of the Interior Hugo de Jonge announced that a spraying ban would also apply to land owned by the National Forestry Service (41 thousand hectares, including 11 thousand hectares of floodplains owned by the Department of Public Works) ‘under further conditions’ . This concerns about 0.2 per cent of the total Dutch agricultural land.

A spokesperson informs that since this month, this ban applies to liberalised leases (short-term with a maximum term of six years). She says: ‘Annually, the RVB issues approximately between 600 and 750 hectares of land where this glyphosate ban will apply.

Playgrounds and primary schools

What exactly are the effects of all that glyphosate?

Scientists have long suspected a link between glyphosate and a variety of diseases. France, for instance, now recognises Parkinson's disease as an occupational disease among farmers. It is also ‘probably carcinogenic’ according to the International Agency for Research on Cancer (IARC). There is some debate about that classification, as it also applies to talcum powder and (too) hot tea. Nevertheless, US producer Bayer has already settled with cancer patients for billions of dollars.

Last year, the television programme Zembla reported on the scientific shortcomings in the authorisation procedure of pesticides such as glyphosate: cancer risks would be structurally underestimated.

Children are particularly vulnerable to pesticide exposure, says Unicef. Their study found that one in 12 Dutch children is exposed to high levels of pesticide pollution. In another European study from 2021, almost all playgrounds surveyed were found to have at least one pesticide.

Follow the Money found at least 176 primary schools in the Netherlands where glyphosate was used within a radius of 250 metres. At 1874 schools, this was the case at a distance of less than a kilometre.

Yellow fields also turn up near playgrounds. At 490 playgrounds within 250 metres, and at 5,437 within a kilometre.

Lazy worms and dying bees

The health risks of glyphosate to humans are still the subject of much debate. What does have scientific consensus is that glyphosate is bad for biodiversity. Bees find it harder to find their way home, photosynthesis in willows deteriorates, earthworms get fat and lazy and fungi grow less well.

A judge recently ruled that lily growers - who use a lot of pesticides - near Natura 2000 areas may have to have a nature licence to use plant protection products. Farmers' organisation LTO Nederland fears that this ruling sets a precedent for all farmers near protected nature areas.

That could have implications for many farmers.

More expensive drinking water supply

The Netherlands has agreed with Europe that no later than 2027, 745 Dutch waters - from small fens and ditches to the Rhine and the Wadden Sea - should be in good chemical and ecological condition. In 2021, none of the water bodies met this requirement, partly because of excess pesticides. Things will not be much different in 2027, the Netherlands Environmental Assessment Agency ( PBL) and the Council for the Environment and Infrastructure (RLI) expect. The RLI therefore called on the Minister of Infrastructure and Water Management to tighten the rules on plant protection products.

Drinking water companies have long warned that pesticides threaten our drinking water supply. In 2022, no standard in the Rhine was exceeded more often than that for aminomethylphosphonic acid (AMPA), a breakdown product of glyphosate.

According to drinking water umbrella organisation Vewin, too many pesticides are found in ‘almost all surface water catchments and in part of groundwater catchments’. A spokesman said that between 2018 and 2022, glyphosate was found above the standards in ‘almost all surface water where drinking water is extracted’. Glyphosate was therefore sprayed in 108 groundwater protection areas in 2020, satellite images show.

To prevent that from getting into drinking water, water companies have to treat the water - and that costs a lot of money, although Vewin cannot say how much. ‘We have to pass those costs back to the customer.’

Take Overijssel, for example. There are 24 groundwater protection areas there, in 20 of which glyphosate has been sprayed.

A necessary evil

Because of concerns about the safety of glyphosate, previous agriculture minister Piet Adema abstained from voting last year during a European discussion on a renewed authorisation of the drug. Investigations by Zembla revealed that Adema had actually wanted to vote against, but was knocked back by coalition partner Mark Harbers of the VVD. Partly because of Adema's abstention, the votes collapsed and the European Commission had to decide. The latter eventually allowed the drug for ten more years.

In 2023, the Ministry of Agriculture, Nature and Food Quality (LNV) asked Wageningen University & Research (WUR) to investigate alternatives to glyphosate. The researchers concluded that while these were ‘mostly’ there, glyphosate was ‘agriculturally and economically’ better. Also, the alternatives would not necessarily be better for humans, environment, soil and climate. The researchers therefore assessed the drug as a ‘necessary evil’.

Last Friday, the minister sent a new WUR report to the House. This showed that for many applications - including the spraying to death of grassland and certain fields - alternatives do exist and ‘the use of glyphosate is not necessary in many cases’. The minister wrote to the House of Representatives to respond to the report ‘soon’.

Bayer, owner of Roundup, is itself also working on an alternative to be launched on the market in 2028. The company hopes this new remedy will generate annual sales of €750 million.

Farming without glyphosate, then, does exist. Organic arable and dairy farmers do not use chemical pesticides at all - but that also translates into lower yields per hectare. However, those organic farmers are in the minority: only 4 per cent of all arable farms are organic.

For now, glyphosate is likely to remain one of the most popular herbicides on the market. For now, a ‘blanket of agricultural toxins’ will still hang over the Netherlands, says professor Violette Geissen. She is therefore not surprised by Follow the Money's findings. Wherever in the Netherlands you vacuum, you will find pesticides in the hoover bag, says Geissen. 'As long as the current form of intensive agriculture persists, there is no need to be under the illusion that you can protect nature reserves or children. The Netherlands is simply too small for that.'

--

Reaction LTO Netherlands

LTO Nederland says: ‘LTO published a press release this morning in response to the attention that crop protection products are receiving at the moment. We have decided to stick to this message for now and not to go into individual questions any further.'

Methodology

This research was initiated by Follow the Money, in cooperation with seven regional media, each of which delved into their own region: RTV Drenthe, NH Nieuws, De Gelderlander, RTV Rijnmond, Omroep Zeeland, De Limburger and De Onderzoeksredactie Brabant (BN DeStem, Brabants Dagblad, Eindhovens Dagblad).

For this research, we used several datasets, including from cultivated crops, satellite data from ESA and several spatial datasets.

To rule out that crops did not yellow due to drought, we used two scientific studies that investigated yellowing caused by glyphosate.

The full technical justification can be found here. The Python code is published on GitHub.