Preparing for consumer interest in the nitrogen cycle

Posted by Jeremy Wiltshire, Principal Consultant on 16 August 2013

It has been estimated that the increase in crop yields from the use of Nitrogen (N) in fertilisers currently provides food for half the world’s population.

With this population predicted to increase to 9 Billion by 2050, Nitrogen will have an increasingly important role in food and drink production. So Nitrogen has got to be good, or does it?

Nitrogen is abundant in the atmosphere as a relatively inert gas, but this cannot be used by plants. They need ‘reactive’ forms of N usually found as nitrate or ammonium. Production of crops for livestock and humans is greatly increased by adding reactive N to soil in the form of fertiliser.

While reactive N is important for providing sufficient food, it has been estimated that less than 20% of N applied to agricultural systems is actually consumed by humans. Reactive N is ‘escaping’ from food production systems with global environmental consequences, polluting water, air and soils; changing natural and semi-natural ecosystems; and affecting the climate. Despite the obvious need to produce enough food, this cannot continue and, while it does, consumer and non-governmental organisations' (NGOs) interest in the N cycle is likely to increase.

The N cycle is a complex set of interacting pathways that reactive N follows as it ‘cycles’ around and through our environment. The N cycle is more important in terms of greenhouse gas (GHG) emissions from food production than the carbon cycle. Nitrous oxide (N2O) is a GHG that has a global warming potential of about 300 times that of carbon dioxide (CO2). For wheat grown in the UK, about two-thirds of the GHG emissions (sometimes expressed as a ‘carbon’ footprint) are associated with the manufacture and use of N fertilisers, and these emissions are dominated by N2O.

So, what can, and should, food and drink companies do to mitigate these issues? The most important action is to gain knowledge of supply chain practices. With this knowledge, companies can use their influence with suppliers to encourage them to use N in more sustainable ways and be ready to present these approaches to consumers, NGO’s and stakeholders when they start to ask questions.

When questions are asked, savvy companies will have answers ready and be able to demonstrate responsible procurement and production so avoiding reputational damage. Just as importantly, an awareness and understanding of the issues, together with supply chain engagement, can increase efficiency in the use of N fertiliser, which will help to control costs.

There is research being undertaken relating to this and a recent Ricardo Energy & Environment report looks at management measures to increase efficiency in the N cycle. The report can be found at

Research like this is crucial to increase understanding of the N cycle and how we can use N to produce crops more efficiently without damaging the environment as we strive to make food production sustainable for the 9 Billion people of 2050.


Jeremy Wiltshire is a principal consultant at Ricardo Energy & Environment with more than 20 years’ experience, working on agriculture and environmental impacts.

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