This article in The Atlantic explores the role that phosphorus - long thought to be a limiting factor in the productivity of the biosphere - plays in the food system. Phosphorus fertiliser has historically come from bones, phosphate rock deposits and human waste. Today, while there are fears of a shortage of mined phosphorus, phosphorus runoff also pollutes water and harms aquatic ecosystems. Companies are now trying to close the phosphorus loop by recovering the fertiliser from human sewage and animal waste.

This paper reviews the literature on the supply chain of phosphorus, a nutrient required in agriculture, and finds that current reporting is inadequate regarding phosphorus reserves and resources, losses along the supply chain, environmental and sociopolitical externalities, and open access to data.

This paper maps the potential for different subnational, national, or regional areas to reduce their agricultural dependence on imported phosphorus fertiliser by recycling manure or urban waste (including both human excreta and household and industrial wastes).

The planetary boundaries concept provides a theoretical upper limit on human activity which the planet is able to sustain without major perturbation to the current ‘Earth system’. Previously, nine planetary boundaries (PBs) have been proposed and recently Steffen et al. (2015) have updated these boundary definitions and assessed the current state of the position of human activity with respect to each boundary. In this article, researchers from a number of food, climate change, agricultural and environmental research institutions around the world build on this work by assessing the impact of agriculture on each PB status, based on a detailed literature review of the available research.

In this post in the Conversation, crop scientist Matthew Wallenstein, Associate Professor and Director at the Innovation Center for Sustainable Agriculture, Colorado State University, discusses the potential of natural microbes to improve agriculture and make it more sustainable. 

This report discusses how less protein in food and fewer phosphorus compounds added to food products could reduce the eutrophication of the sea. Below is a summary of the research by two of the report’s authors, Anders Grimvall and Eva-Lotta Sundblad from the Swedish Institute for the Marine Environment.

This paper published in Nature Plants finds that if tropical farming intensifies, major additions of phosphorus to soils will be needed

In this study, researchers from the Netherlands and Italy investigate the long-term (past and future) changes in phosphorus (P) budgets in grasslands used for grazing and in connection with croplands. The authors recognise a lack in the literature of studies characterising the P cycle in relation to grasslands and croplands, and - as grass-dependent livestock demand is increasing – they seek to address this lack of understanding.

The journal Ambio has a special issue devoted to minimised phosphorus losses from agriculture. The papers cover topics such as: the need for stewardship to tackle global phosphorus inefficiency in Europe; past, present, and future use of phosphorus in Chinese agriculture and its influence on phosphorus losses; and modelling of critical source areas for erosion and phosphorus losses.