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The potassium cycle to feed the city

Lookup NU author(s): Professor Oliver Heidrich, Professor David ManningORCiD, Dr Alistair FordORCiD, Dr Luca Panzone, Dr Natalia YakovlevaORCiD


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For centuries fertilisers are being added to enhance the fertility of the soil; adding three main macronutrients: Nitrogen (N), Phosphorus (P) and Potassium (K). N and P, its supply and recycling are well documented (Chen and Graedel, 2016), whereas potassium is less investigated, perhaps due to large deposits of mineral resources (KCl) existing in the northern hemisphere, which do not pose any immediate threat to supply shortages in that area of the world (Ciceri et al., 2015). In 2016, planning permission was granted to Sirius Minerals Ltd to mine potassium (K) from the mineral polyhalite in North Yorkshire National Park, UK. We show the impacts of such local decision on a global scale by illustrating the supply risks of K fertiliser considering the global and urban metabolism. More than 90% of all potassium mined is used as fertiliser. Importantly there is no sink of potassium other than the sea and recycling is unfeasible with currently available technologies (Manning, 2015). K is of key importance to global and local policy, but interactions are constrained by providing separate policies. Supplies of potassium have been raised of highest concern especially in Africa and material flow accounting can help to identify the scale of the problem and the potential solutions (Sheldrick and Lingard, 2004; Fernández et al., 2015). We developed a database that quantifies and illustrates the global and urban metabolism of potassium needed to feed the city. We show the supply and consumer chain of K from ‘mine to mouth’ using material flow and life cycle assessment principles. Using food composition data we calculate the human potassium intake, based on average daily food intake, diet and census data for the North East of England and the city of Newcastle. We link this back to the global potassium production using COMTRADE database and quantify the demands. Despite supposedly available potassium, we identify potential bottlenecks of supplies for Western cities and discuss larger problems of nutrient loss and soil conditioning for the cities in the Southern Hemisphere. We make recommendations to address the problems by improving e.g. the use of non-renewable resources for food production and the supply and consumption of potassium that are related for example to diet, alternative fertiliser provision and recycling. References Chen, M. and Graedel, T.E. (2016) 'A half-century of global phosphorus flows, stocks, production, consumption, recycling, and environmental impacts', Global Environmental Change, 36, pp. 139-152. Ciceri, D., Manning, D.A.C. and Allanore, A. (2015) 'Historical and technical developments of potassium resources', Science of the Total Environment, 502, pp. 590-601. Fernández, J.E., Musango, J.K., Currie, P., Dudek, P., Kim, J., Lay-Sleeper, E. and Norford, E. (2015) 'A Typology of African Urban Resource Consumption', International Society of Industrial Ecology-Taking Stock. Surrey, UK, July 2015. International Society of Industrial Ecology. Available at: Manning, D.A.C. (2015) 'How will minerals feed the world in 2050?', Proceedings of the Geologists' Association, 126(1), pp. 14-17. Sheldrick, W.F. and Lingard, J. (2004) 'The use of nutrient audits to determine nutrient balances in Africa', Food Policy, 29(1), pp. 61-98.

Publication metadata

Author(s): Heidrich O, Manning D, Ford A, Panzone L, Yakovleva N, Fernandez J, Ciceri D, Allanore A, Villarroel-Walker R

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Published

Conference Name: 9th Biennial Conference of the International Society for Industrial Ecology (ISIE)- Science in Support of Sustainable and Resilient Communities

Year of Conference: 2017

Print publication date: 26/06/2017

Online publication date: 26/06/2017

Acceptance date: 01/01/2017

Publisher: ISIE


Series Title: Science in Support of Sustainable and Resilient Communities