Peddling manure

^{Text: Albert Sikkema | photo:ANP/Nico Garstman}

^{This article appeared in Wageningen World 2|2025, the magazine of Wageningen University & Research.}

For more than 40 years now, the pigs, cows and chickens farmed in the Netherlands have been producing more manure than livestock and arable farmers are allowed to spread on their land under environmental rules. For decades, pig and chicken manure has been exported, mainly to arable regions in Germany and France where there is a demand for more manure. Dairy farmers with plenty of land could still use most of their manure on their own or neighbouring fields.

But last year saw a sudden ‘manure crisis’. The EU decided to phase out the derogation – the exemption that allowed Dutch dairy farmers to spread more manure on their land than was allowed by the rules. The nitrogen applied per hectare would have to decrease in steps from a maximum of 230–250 kilos in 2022 to a maximum of 170 kilos by 2026. This meant the amount of manure dairy farmers could spread on their land was 15 per cent less in 2024 and they had to trade the excess manure. That led to an even bigger supply of manure on the market. It’s an unusual market because the surplus means that rather than being paid for their manure, livestock farmers have to pay the arable farmers to take the manure off them. Last year, livestock farmers were paying 30 euros per cubic metre to offload their manure, twice as much as in 2022. Arable farmers joke that manure is an extra crop as they can earn good money by taking it in.

The manure market varies depending on the farm animal. Intensive pig farms have been exporting their manure for years. Manure dealers often have sales channels abroad. The poultry sector has its own distribution channels. Most poultry manure is processed. A proportion is dried and then sold to garden centres or exported. Some of the manure is incinerated in a power plant in Moerdijk; the poultry farmers pay for this. The ash, which contains phosphate and valuable minerals, is then exported.

In 2024, the markets had to deal with the additional surplus manure from dairy farmers as well. As a result, Dutch manure exports increased in 2025: data from the Netherlands Enterprise Agency shows manure exports were up by 30 per cent in the first half of 2025 compared with the same period in 2024.

Pig and cattle manure is separated into solid and liquid fractions before exporting it. The solid fraction, which contains phosphate, makes up most of the export. The liquid fraction is also valuable as a fertilizer as it contains nitrogen and potassium. The liquid is often evaporated off or concentrated before transport – mainly to destinations within the Netherlands – to avoid having tankers transporting mostly water. The price paid to offload the manure is primarily determined by the transport and processing costs.

Buyout scheme

The derogation phase-out is already affecting Dutch livestock numbers and manure production. The extra costs of offloading the manure led to a big drop in income for many livestock farmers in 2024, according to calculations by Wageningen Economic Research. That was an extra incentive for farmers to take part in the buyout scheme, organized by the government as a way of tackling the nitrogen crisis. The scheme applies to about 1,500 farms.

In July, Statistics Netherlands announced that the pig population had fallen below 10 million for the first time in 45 years; as recently as 2018, the Netherlands still had 12.4 million pigs. The number of cows also fell last year, by 3.3 per cent. The smaller livestock numbers also meant a fall in manure production, which was lower than it has been in the past 30 years, according to Harm Smit, Emissions & Manure Valorisation project manager at Wageningen Livestock Research. ‘I expect the decline to continue in the next few years.’ This is already having a noticeable effect in certain regions. For example, ammonia emissions in the Gelderse Vallei area have fallen by 30 per cent because livestock farms have been bought up.

Despite the falling manure production, the Netherlands still has a manure problem. That is because as the derogation is phased out, the application standard for manure has been reduced at a faster rate than the manure production. ‘We are still in a situation where farmers have to pay to offload their manure,’ says Gerard Ros, an environmental researcher in the Earth Systems & Global Change group and a researcher at the Nutrients Management Institute. ‘In 2024, 87 per cent of dairy farms produced more manure than they could use, as did 94 per cent of pig and poultry farms. That’s a problem.’

In these areas, farmers are once again having to figure out how to optimize crop yields using various fertilizers. Grassland needs 350 kilos of nitrogen per hectare per year to grow well. Before the derogation phase-out started, farmers could apply 230 to 250 kilos of nitrogen in the form of manure and then add 100 to 120 kilos of artificial fertilizer. Now that they need to reduce the application of manure to 170 kilos, they will have to use more artificial fertilizer to give the land the remaining nutrients it needs.

Farmers complain that the current scheme forces them to purchase more artificial fertilizer. Why can’t they simply use the manure from their own farms as in the past? Ros: ‘We know that 70 per cent of the nitrogen in animal manure becomes available to the plants but the remaining 30 per cent ends up in the soil and wider environment.’ Most of the nutrients in artificial fertilizers can be absorbed directly by the plants.

Renure as substitute

But there is a development that can help farmers to limit the nitrogen losses from livestock manure. In September, the EU’s Nitrates Committee, which consists of soil and fertilizer experts from EU countries, agreed to admit Renure as a substitute for artificial fertilizer. Renure stands for recovered nitrogen from manure; it is manure that has been processed so that nutrients such as nitrogen become available in a more usable form. Smit: ‘Farmers will then be able to make more use of the nitrogen in manure and more of the manure can be used in the region.’ To make Renure, farmers can choose between processing their manure on the farm and sending their manure to processing plants, possibly in combination with the production of biogas.

The approval of Renure will reduce the pressure on the manure market because livestock farmers can use more of their nitrogen on their own farms. But there are still issues with this solution. Research shows Renure is slightly less effective than artificial fertilizer, which means emissions may get into the air or water. That is why the EU’s proposal to allow Renure is subject to conditions. For example, the Renure must contain more than 90 per cent mineral nitrogen – nitrogen that is directly available to the plant – and farmers cannot use more than 80 kilos of Renure per hectare per year. In addition, the fertilizer has to be applied using low-emission technology.

All in all, livestock farmers will have to make substantial investments to be able to use Renure. Nor does it mean an end to the manure problem. The derogation is still being phased out, with the maximum falling to 170 kilos of nitrogen in 2026. There could therefore be another manure crisis in spring 2026, says Ros. ‘Farmers are not allowed to spread manure from 1 September to 15 February, but manure production continues during that period so all the slurry pits are full by the end of the winter. Farmers are therefore keen to get rid of their manure as soon as possible in the spring. Spring 2024 was very wet, so farmers were unable to drive their heavy machinery onto the fields to spread the manure – and a crisis arose. Last spring (2025) was dry and the farmers were therefore able to spread manure, but they will be panicking again if next spring is wet for manure spreading.’

Solutions

To conclude, manure is still costing Dutch farmers money. What can be done about this? Ros and Smit see a future in a combination of three solutions. First, livestock numbers should be reduced further. This is currently being achieved mainly through the government’s buyout scheme for farms near nature areas that are vulnerable to nitrogen. Second, improve the processing and export of manure. There was already a big increase in manure exports this year, but the Ministry of Agriculture believes further expansion is possible. In 2025, it visited Germany, France, Poland and Romania in efforts to promote manure products. There could also be more manure processing for domestic use now that products such as Renure are being allowed.

A third solution is to reduce the protein content of animal feed. High-protein animal feed gives manure with a lot of nitrogen. Lowering the protein content to levels that are safe for animal health will help tackle the nitrogen problem too. Applied research at Wageningen with dairy farmers shows that they can still achieve good milk production if the nitrogen content in the feed is less. If the lessons from these practical experiments are adopted on a large scale, this measure could have a considerable impact on the nation’s nitrogen production.