Nitrogen Reduction, Recycling and Reuse (Environment and Climate Change Committee Report)

Lord Trees Excerpts

Tuesday 6th January 2026 Grand Committee

[Lord Trees (CB)]

My Lords, I am pleased to say that it is a great pleasure and privilege to sit on this committee. I thank our chair for her huge amount of hard work and excellence in chairing; I also thank the clerking team, our policy analyst and Mark Sutton, our expert adviser.

There is a notable irony to the issues around nitrogen—sometimes referred to as “the nitrogen paradox”, as the noble Baroness, Lady Bennett, said—in that nitrogen is an important chemical element that comprises nearly 80% of the atmosphere, is harmless and is essential for many biological functions, but too much of it in the wrong form, in the wrong place, at the wrong time is deleterious to the health of humans and the environment, is economically wasteful and exacerbates climate change. It can become a pollutant to be dealt with, yet it is a potentially valuable resource.

Although there are a number of other sources of nitrogen derivatives, I want to concentrate on agriculture, since the majority of ammonia and nitrous oxide in the air—as well as the majority of nitrate pollution in water—comes from agriculture, as my noble friend Lord Krebs pointed out. We expend time, money and much energy on capturing innocuous nitrogen from the atmosphere and then turning it into fertiliser, which we sometimes apply excessively, leading to derivative nitrogen compounds creating problems.

Nitrogen cycles are complex, and nitrogen balance sheets can be constructed to understand the sources, flows and sinks of nitrogen and its derived compounds in order to prioritise actions. That has been done by the Scottish Government but the UK Government did not accept our report’s recommendations to create a nitrogen balance sheet for England. I find it difficult to understand how a Government can then assess the most cost-effective interventions that can be advocated or supported without such a balance sheet. However, I note that His Majesty’s Government acknowledged the need to consider how the nitrogen balance sheet is working in Scotland. Have the Government reached a conclusion yet about this since the Scottish nitrogen balance sheet has been operating for some four years and a considerable amount of data is now available to assess it?

Notwithstanding that, many witnesses to our report have advocated for a circular economy approach. The Government acknowledge such an approach and that it is essential to have a holistic systems approach in order to achieve that. However, His Majesty’s Government have argued that the Circular Economy Taskforce, which will produce what I think is now called the circular economy growth plan, will address nitrogen pollution. Can the Minister tell us what progress has been made in developing approaches to include the nitrogen problem in agriculture and to develop a specific roadmap for farming, which has been promised for 2026?

There are several key challenges facing the agriculture sector to address nitrogen pollution. The first is how to reduce the excessive application of synthetic fertiliser while increasing the use of low-emission applications; as has been said, 45% of fertiliser applied to land is lost to the environment. Secondly, though, there is a need to better store, use and refine livestock waste as fertiliser. Meeting these challenges partly requires the consolidation of policy regulations regarding air and water pollutants, but I will leave that for others to discuss. The noble Lord, Lord Ashcombe, has touched upon that issue.

I want to concentrate on technical applications and solutions that could be encouraged and partly enabled by the Government and communicated to and by farmers. Precision farming methods provide a means of determining appropriate amounts of fertiliser to be applied to relevant crops and soils. An application by injection can reduce leakage to the environment. Low-emission spreading technologies are critical in this respect. Covering slurry tanks substantially reduces emissions of both nitrogen pollutants and other greenhouse gases such as methane. However, covering slurry tanks should be coupled with low-emission spreading for optimum effect.

Additionally, new design standards for livestock housing can reduce airborne pollutants, as we saw in our visit to Netherlands. We also saw there that the requirements that I have just described have been implemented successfully, which has led to a reduction in ammonia emissions by 64%.

In the UK, while funding to cover slurry tanks is available for new slurry stores, it is not available, as I understand it, for existing stores. Covering all slurry stores could bring immediate effects in reducing nitrogen and other greenhouse gas emissions. The revised Environment Improvement Plan stated that the Government would support farmers to invest in low-emission equipment and infrastructure, such as slurry covers, through capital grants. I ask the Minister what progress has been made in that respect.

A better, more circular use of nitrogen is complicated in the UK by the geography of agricultural land use in Britain, as the noble Lord, Lord Ashcombe, referred to. Fertilisers are needed particularly for arable crops in the south and east, and synthetic fertilisers are applied in large quantities there, whereas much of our manure is produced in the west of England, where the majority of livestock are, although the distribution is less marked for pigs and poultry.

Making better use of animal waste is compromised by its sheer bulk, which is mainly water, because this makes mass transport challenging and costly. In 2014 in the Netherlands, legislation was introduced to require the separation and drying of slurry. The creation of dry pelleted animal-derived fertiliser has created a new economic activity, which enables organic fertilisers to be easily and economically transported from their source to the point of need. This reduces imports of synthetic fertiliser and mitigates the insecurity in the supply volatility of international fertiliser.

It is encouraging that, in the UK in 2024, 8% of farms were concentrating and drying slurry. In our inquiry, we heard about encouraging innovative commercial developments, notably from one UK company which makes pellets from organic fertiliser and expects to produce its product at the same cost as synthetic fertiliser within a year. Use of this capital-intensive technology will require the collaboration of multiple primary sources of manure or slurry and commercial plants. The downscaling of such plants, as is being developed and looked at in the Netherlands, could make the production of pelleted organic fertiliser viable by single large enterprises or co-operatives of a few farms. What measures have the Government introduced —or are they considering introducing—to encourage these practices in the UK? They would be a game-changer in facilitating a circular economy for nitrogen.

In conclusion, a comprehensive nitrogen strategy should be an important part of farming, environmental and water strategies and should link up these entities. It is regrettable that His Majesty’s Government are not inclined to develop this. The farming road map due in 2026 will be significant in defining tactics to derive a more circular economy in the agri sector. We look forward to His Majesty’s Government’s considerations of the effectiveness of the national nitrogen balance sheet in Scotland. What are the Government doing to facilitate information, knowledge exchange and best practice to advise farmers how to reduce nitrogen pollution and to address some of the low-hanging fruit issues?

Finally, recognising the old adage “where there is muck, there is money”, with imagination, enterprise, commercial initiatives and appropriate government incentives, real progress could be made in creating an environmentally and economically successful circular economy for nitrogen in the agriculture sector.