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N & P:  The two nutrients at the heart of the farming and planetary challenges

Download the two reports Nitrogen in the Food System and Strategies to improve the efficiency and decrease the negative environmental impacts from phosphorous fertiliser use

This issue of the BHU Future Farming Centre Bulletin focuses on the nutrients nitrogen and phosphorous.

Nitrogen (N) and phosphorous (P) are the fourth and fifth most important nutrients / chemical elements for life (after carbon, oxygen and hydrogen). They are the two most important nutrients / fertilisers used to grow humanities food. However, the way we have been managing them, going back to the start of the industrial revolution, has made them the third most transgressed planetary boundary after biodiversity loss & novel entities and bigger than climate change. Their inappropriate use is therefore the third biggest planetary risk of causing biosphere collapse and thus ending civilisation.

Post-industrialisation their movement through the planet’s biogeochemical systems changed from being cycles at human time-scales to streams. Thus the current management of P parallels fossil fuels. We are mining fossil reserves of P, putting on land to grow food, eating it, and sending the P in our manure out to the oceans whence we cannot get it back. Current estimate are that in about 300 years P supply will fail, and with it agriculture and society.

At least for N the planetary reservoir is the atmosphere which is 79% N and thus inexhaustible. However, synthetic N now accounts for half the reactive N in the biosphere and the existence of about half the worlds population – 4 billion people only exist due to synthetic N fertilisers. Half the N in your body was made in a factory not on a farm. [1]  [2]  [3]. And counterintuitively while it is an essential nutrient, excess amounts are killing large parts of the biosphere, such as the oceanic dead zones [4], and degrading ecosystems.

N & P thus represent one of the most challenging dilemmas facing humanity. N & P are utterly critical for life and thus essential fertilisers for farming, and thus essential for civilisation, but, our management of them is causing the destruction of our home, the biosphere, and thus threatening humanities very existence.

These two reports, serendipitously published at the same time and independently taking quite similar approaches, provide at a lay level, the whole picture of N & P: why they are essential, their human histories, what has gone wrong with our management of them, comparing their similarities and differences, and a pointing to what has to change to ensure we manage them correctly to maintain civilisation and our home the biosphere.

Nitrogen in the Food System is written by Dr Rasmus Einarsson of the Swedish University of Agricultural Sciences and published by TABLE https://tabledebates.org/

Strategies to improve the efficiency and decrease the negative environmental impacts from phosphorous fertiliser use is written by Dr Charles N Merfield Head of the BHU Future Farming Centre and published by Our Land and Water – Toitū te Whenua, Toiora te Wai.