The main research question of this thesis was: Can nitrogen cycling on dairy farms on peat soil in the Dutch Green Heart area be improved by adapting management to the nitrogen supply from soil and by using other grassland species and crops without affecting milk production?

Environmental organisation Greenpeace wants to see a drastic reduction in nitrogen deposition on the Netherlands’ most vulnerable nature conservation areas. This would extend beyond the nitrogen targets that the Dutch government is currently striving to meet. Rogier Kegge, Assistant Professor of Constitutional…

The elementary excitations of magnets are called spin waves, and their corresponding quasi-particles are known as magnons. The rapidly growing field of Magnonics aims at using them as information carriers in a new generation of electronic devices, (almost) free of electric currents.

The use of N fertilizers has increased worldwide in the past century. While this increased input of N has increased food productivity, it has also contributed to decreases in biodiversity, soil quality and environmental health, including increases in greenhouse gas emissions.

Strengthening nature and at the same time investing in future-proof agriculture. That is the task of the Minister for Nature and Nitrogen, Christianne van der Wal. It is also the lifework of Leiden professor Jan Willem Erisman. He has been researching nitrogen for his entire career and has shown that…

Statements made by Caroline van der Plas about nitrogen emissions and European law are incorrect: Armin Cuvyers on Dutch radio EenVandaag programme’s item ‘fact or fiction’.

On 5 October, mediator Johan Remkes presented his report on the nitrogen crisis and what he thinks is the best way forward. Leiden University professor and nitrogen expert Jan Willem Erisman responds to Remkes’s recommendations. ‘It’s a step in the right direction.’

At present, the cabinet still maintains that all provinces are motivated to cooperate with the sensitive issue of the nitrogen strategy. However, there are major concerns that the political landscape will look very different once the elections for the Provincial Councils on 15 March have been held.

These might be ‘just’ provincial council elections in the Netherlands, but the outcome on 15 March could have serious consequences for how the country is governed. Conflicts between the government in The Hague and the provinces, and tension within the Dutch cabinet, might be looming. On 1 July, every…

In an essay Professors Jan Willem Erisman (Leiden University), Chris Backes (Utrecht University) and Wim de Vries (Wageningen University) suggest amending nitrogen policy in the Netherlands. They call for a shift from a deposition to an emissions policy, with sectors responsible for reducing their own…

Relatively simple adjustments can reduce nitrogen losses on dairy farms in peatland areas. That’s the conclusion of the PhD research by by Leiden environmental scientist Jeroen Pijlman at the Louis Bolk Institute. Protein-poor grass species and narrow-leaved plantain in the grassland can limit nitrogen…

This semester we again organize the elective Nitrogen and Sustainability for 36 master students mainly from Industrial Ecology and Governance of Sustainability. The course helps the students to understand the complexity of the Dutch nitrogen crisis and the role different stakeholders play.

Dutch provinces must finalise their plans this summer to meet the government's targets on nitrogen emissions. Can the outcome of the provincial elections this week still change nitrogen policy? The NOS spoke about this issue with various parties including Rogier Kegge, assistant professor in administrative…

There is no time to lose when it comes to repairing damage to nature. For that reason and to show that the European Commission is neither a ‘bogeyman’ nor an enemy, European Commissioner Frans Timmermans came to the Dutch House of Representatives to talk with Caroline van der Plas, leader of political…

In his inaugural lecture Professor of Environmental Sustainability Jan Willem Erisman calls for local solutions that give people more freedom in how they meet environmental, nature and climate goals. This would allow farmers to come up with their own solutions to the nitrogen problem. The idea ties…

The new Dutch government must act quickly to take rapid, far-reaching measures in three specific regions to tackle nitrogen emissions. This will create the space for a long-term strategy to deal with other urgent problems and the knot of obligations that the state will need to untangle. These are the…

By reforming agriculture in targeted areas, we can protect the Natura 2000 areas much more effectively. This is what Jan Willem Erisman of Leiden University and Ton Brouwer of Gispoint consultancy write in a new report. They have created a special, nitrogen map of the Netherlands that shows the areas…

Nitrogen deposition does not only affect plant biodiversity, but also strongly affects the composition of the remainder of the food web, through the changes in plant composition. In an unprecedented analysis of population changes of butterfly and moth species, an international research team including…

The Netherlands is embroiled in a complex nitrogen crisis. Berent Baris wants to use his NitroGenius game to demonstrate the complexity of this crisis.

Rogier Kegge, Assistant Professor at the Institute of Public Law of Leiden University, was interviewed by Dutch newspaper de Volkskrant in response to the recent recommendations by Johan Remkes on how to approach the nitrogen crisis.

Politicians in The Hague were in for an unpleasant surprise when the interview with CDA politician, and also current Dutch Foreign Affairs Minister, Wopke Hoekstra was published. Especially Hoekstra’s suggestion to let go of the Government’s target to reduce the amount of nitrogen by 2030 raised some…

They were eagerly awaited: four letters from five ministers that should provide clarity on how to get us out of the nitrogen crisis. Nitrogen expert Jan Willem Erisman explains the plans. And says whether they will get us out of the nitrogen crisis.

Freshwater biodiversity has been threatened by eutrophication due to excessive nutrients in the environment. Releasing the freshwater species from such pressures requires efforts from industry and manufacturers to avoid emissions to vulnerable and high-risk regions.

Opponents of drastic nitrogen measures argue that the nitrogen calculation model is not reliable enough. Nitrogen professor Jan Willem Erisman: 'It is now much more important to discuss the choices we make on the basis of the outcome. The differences are much bigger than the uncertainties in the mod…

Advanced sensing techniques require graphene with high quality and well-controlled surface chemistry.

Vinasse is a major by-product generated by the sugarcane biofuel industry. It is a source of microbes, nutrients and organic matter and often it is recycled as fertilizer.

The Vrouw Vennepolder near Oud Ade has been transformed into the Polderlab. Scientists and students from Leiden University, together with farmers and citizens, investigate how to manage peatland in a sustainable and profitable manner. A great opportunity for students to experience how scientific knowledge…

The Cryogenics Department has a liquid helium production unit and an automatic liquid nitrogen filling plant.

Even a small quantum computer should be able to simulate exactly the properties and behaviour of new molecules. This would take chemistry to an entirely new level. Better solar panels, more powerful batteries, saving lots of energy in the chemical industry: the applications have the potential to transform…

Promotor: Prof.dr. H.V.J. Linnartz, Co-Promotores: S. Ioppolo, H.M. Cuppen

Door onduidelijke stikstofregels komen milieuzaken steeds vaker voor de rechter. De zaak van een Reeuwijkse varkenshouder leidt al tientallen jaren lang tot een getouwtrek tussen een milieuorganisatie, de provincie en de rechter. Rogier Kegge, universitair docent Staats- en bestuursrecht, bespreekt…

Food production in the Netherlands is an economic success but has led to many environmental issues, including nitrogen pollution. Recently, the policy to allow economic growth while reducing nitrogen losses was disapproved by the highest court in the Netherlands, casting the country into a nitrogen…

Voters sent a clear signal in the recent Dutch provincial council elections with the 'monster' victory for the Farmer-Citizen Movement (BoerBurgerBeweging, BBB). This sign of ‘social resistance’ has consequences for the policy on nitrogen emissions, according to Geerten Boogaard, Professor of Local…

Planets are formed in disks of gas and dust around young stars.

Materials balances have been used in the recent past for the analysis of substance oriented environmental problems and the formulation of measures for environmental policy. In this study an integrated tool, based on the materials balance principle, has been developed for the analysis of both environmental…

These podcast episodes were written for the Green Office’s Spring Podcast competition and miniseries 'Beyond the Safe Space', on the theme: the Planetary Boundaries, which took place between the months of March-May 2023.

Can we enhance the capacity of host immune cells to kill mycobacteria via production of reactive nitrogen species?

It’s better to cut our nitrogen emissions now than to solve the consequences later at great expense. That’s the lesson we can learn from the Dutch nitrogen crisis, according to nitrogen expert Jan Willem Erisman. In Science, he shares this lesson with other countries. According to Erisman, we should…

Crises like climate change and loss of biodiversity threaten our planet. That’s why sustainability is an important topic in research and education across Leiden University. On this website you read how scientists from many disciplines work together in researching sustainability.

The research within the Food research programme at CML focuses on a transition towards sustainable food production and consumption systems. We investigate from a very small to a very large scale, at a local, national or international level. We do so by researching for example molecular tools, food systems,…

List of Support Departments at LION and the Faculty of Science

A dense region of a gaseous and dusty cloud collapses to form a protostar surrounded by a disk and an envelope. This thesis uses both observations and models to study physical and chemical conditions of these protostellar systems which are likely where planets start to form.

Marc Koper’s research focuses on electrocatalysis and electrochemical surface science for sustainable energy and chemistry. Reactions of interest are the redox reactions of the oxygen/hydrogen cycle (water oxidation, hydrogen evolution), the carbon cycle (reduction of carbon dioxide, oxidation of small…

Associate professor at the Natural Products Laboratory, Institute of Biology, Leiden University - the Netherlands

One of the key discoveries in exoplanet research over the past decade is the abundance of small planets in our Milky Way. Despite their high numbers, our understanding of their atmospheres remains limited, and it is unknown if they possess atmospheres at all.

The marine shipping industry is one of the strongest emitters of nitrogen oxides (NOx), a pollutant detrimental to ecology and human health. Over the last 20 years, the pollution produced by power plants, the industry sector, and cars has been decreasing.