Science of the Total Environment 542 (2016) 1005–1007

Contents lists available at ScienceDirect

Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv

Editorial

Taking Stock: Phosphorus Supply from Natural and Anthropogenic Pools in the 21st Century Keywords: Phosphorus Supply risk Scarcity Recycling Food security Environmental health Residual soil phosphorus century

It is hardly necessary in the 21st Century to debate the importance of phosphorus (P) in soil fertility and crop production. Phosphate rock (PR), in particular, has become a cheap, easy, and efficient resource in P fertilizer production and has more than demonstrated its usefulness, including the plethora of phosphate applications beyond fertilizers. However, there is a downside: P as an element can impair the environment and PR is a finite resource. The renewed recognition of the pivotal role of P as a pillar for global food security and environmental health and the realization that the current use patterns are hard to sustain have sparked many activities and cooperative actions toward better nutrient management practices on the part of politics, administration, business, industry, and science. It has become obvious that sustainable P management as part of improving the management of our natural resources has become an important topic for research, policy making, and technological progress at a global scale. This trend can be seen not only in the numerous platforms, communications, and scientific articles but also in a number of special issues or sections by international journals, such as Elements, Chemosphere, Nutrient Cycling in Agroecosystems, and Frontiers. Progress is cumulative. If we want to appreciate the contemporary challenges posed by phosphate supply security risks, it is necessary to look at the evolution of concerns and the transformation of related discourses. Research shows how P depletion concerns were constructed and destructed repeatedly in the past and demonstrates that scarcity debates are historical artifacts (Ulrich and Frossard, 2014), a finding that is illustrated by the front page of The Fertilizer Review of 1938 (Fig. 1). The answer to the continual question if humanity will physically run out of P—often conceptualized as running out of PR—at a certain manageable time has been negative. Moreover, there are lessons to be learned that can help in moving beyond the decades-old problem-framing habits and rethinking the conventions of P management. The notion of repetition can be accepted or dismissed; most often, though, it is ignored. While this risks the continuation of the historical logic of repetitive P scarcity debates, there are possibilities for future change. Questions

http://dx.doi.org/10.1016/j.scitotenv.2015.10.036 0048-9697/© 2015 Elsevier B.V. All rights reserved.

for a deeper understanding of the challenges for P sustainability seem to have matured. Possibly they could not be considered in their totality in the past let alone answered because they did not fit the thinking at the time. Today, we are offered a unique opportunity to give the supply security risk debate as part of the sustainable P discourse a different twist—namely one in which the geologic PR depletion narrative no longer dominates as the main driver for sustainability strategy thinking. This singularity or dominance of how to frame the problem neglects the complexity of challenges and alternative ways of action. We may now be initiating a bigger transition, one in which not just a selected view but all relevant environmental, social, and economic aspects of P supply and use are being considered together. None of this will come easily—and certainly not quickly. Moreover, it will require a new generation of scientists and practitioners that deliberate and help implement a much broader if not fuller meaning of P sustainability. Current examples from the energy sector or the electric car industry show that alternatives exist and have matured. What it will take for them to overcome the long-standing status quo or dominance remains to be seen. Will we, in the 21st Century, enter a new P supply reality? Is it already on its way? This special issue is dedicated to P supply security considerations. It is built around the idea of taking stock. In an attempt to answer questions on the availability and accessibility of primary and secondary sources, we reached out to experts from science and practice. Sixteen papers were prepared or selected especially for this edition. They integrate multiple perspectives and different spheres of the environment to take a larger system-level view, report on different active research areas about natural and anthropogenic P stocks and address the significant challenges of advancing our understanding of pools and vulnerabilities to supply security in various parts of the world. The issue is characterized by inclusion and diversity to underline not only the quintessence of the element but also the totality approach. The aim of this issue is to provide a better understanding of interrelations and transitory pathways toward sustainable P management via a supply security lens and, in doing so, to open new discussions and stimulate engagement and action. The first set of papers focuses on the supply of P from three essential primary resources, phosphate rock, soil P stocks, and animal manure, as well as on the related environmental aspects. In an invited opinion paper, Mew—reflecting a rare practice perspective—draws attention not only to the interaction between PR mining costs and prices but also to disentangling questions about the physical adequacy of PR resources and economic access. The role of the kiln process in the future provision of phosphoric acid is not presented. Dr. Joseph Megy, who had prepared a manuscript for this issue, regrettably

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Editorial

Fig. 1. Cover of The Fertilizer Review Vol. XIII, March–April 1938, No. 2, illustrating the role of the undeveloped Western phosphate deposits in U.S. phosphorus supply considerations. The year 1938 had the highest phosphate rock (PR) production on record, coinciding with large exports of high-grade PR from Florida and substantial phosphorus-depleted soils in the U.S. Depletion concerns about national PR reserves were eminent at the time but could not be substantiated.

passed away. This is a great loss to technology and the practice community. Because of the importance of this topic and the valuable time spent on preparing the manuscript, I would like to refer to Fowler (2014), who offers insights into the promises of the Improved Hard Process among the economic processing techniques of low-grade phosphates. Fowler discusses some aspects of the long-standing dominance of the wet acid process in manufacturing phosphoric acid as a basis for mineral fertilizer production. The following papers included in this edition underline a topic of large significance as they couple primary resource supply (PR and animal manure) and use with environmental considerations. While mineral fertilizers from PR may contain high levels of heavy metals that generate risks for long-term environmental health (Kratz et al.), Xie & Zhao find that P leaching from poultry litter can be controlled by nanoparticles. Ulrich et al. suggest that the path of coupling overabundance and scarcity thinking in reversing eutrophication and shifting from symptom to driver elimination depends on knowledge transfer, and asks for a joint approach by actors from administration, industry, and society. They contend that a democratic involvement approach in the form of inclusiveness is a more effective way to the sustainable management of resources. On the contrary, Viscarra Rossel and Bui evaluate a crucial stock that has not been included in the P supply debate to the extent it should be: residual soil phosphorus. They model and map total soil P stocks over Australia and show that many areas have a surprisingly high level of soil P. Pavinato et al. discuss the limited soil P supply in the

Brazilian Cerrado and the best management practices to make better use of this largely unutilized P pool. Similarly, Lukowiak et al. discuss improved soil management practices in the soil–plant system in Poland to better exploit legacy P. The second set of papers is concerned with new secondary P sources and their potential and role for recovery and reuse in the future. Using this potential is crucial for sustainability. Nevertheless, recycling is no magic bullet that will solve all supply challenges, but it is a promising approach to solve of several problems, including resource conservation, import dependency, price volatilities in international markets, and mineral fertilizer quality concerns. The papers by van Dijk et al., Wu et al., Thitanuwat et al., and Metson et al. provide a better understanding of the role of recycling in the future by tracking P flows at an urban, multistate, or supranational level. This set of papers focuses on promising innovative pathways of change by highlighting P losses and thus the recycling potential. This is a welcome shift as it holds various potentialities. The reality though is that these shifts bring their own technical, environmental, economic, and social challenges. Hukari et al. look at these challenges from a regulatory perspective. They examine the European Union (EU) legislation relevant to P recycling and suggest that appropriate governance be put in place to enable reuse and market access. To some degree, they discuss part of a larger question, that is, what it takes to make fertilizers from secondary sources more than a market oddity. It remains debatable how products from secondary P sources will funnel in the industrial fertilizer production process, a complex net of integrated activities on a global scale that reflects certain inertia. To redesign a whole industry will likely take decades. Moreover, several recycling pools, obviously still under development, are presented in their current state. Herzel et al. bring up the important point that the direct use of sewage sludge ash as fertilizer is often not possible due to heavy metal loads and low P bioavailability. Hupfauf et al. perform a comparative study on the fertilizing effects of different primary and secondary resources. Krähenbühl et al. focus on yet another secondary source, struvite, a P fertilizer that can be recovered from source-separated urine by means of adding soluble magnesium. They suggest a broader angle on secondary P production for fertilization by focusing on another process-related important resource, magnesium. Finally, Matsubae et al. recap the history of P recovery from steelmaking and its application in agriculture. They calculate that the hidden P flow in steelmaking is equivalent to 4% of the global P supply, and they underline the future role of steelmaking in P supply security. The papers presented in this issue deliver new helpful information on pathways for a more sustainable P supply and use. Perhaps more than anything else, the articles show a continued trend of efforts and areas of involvement to increase our understanding of the problems and to find sound ways forward. As a whole, they suggest that there is not one single answer and not one single way to address questions of secure supply. The papers have shown the need for a combined approach of progress in different fields. Moving forward, there is much to do for a more sustainable supply and consumption. This will require going beyond technological and environmental considerations to more strongly include economic, societal, and ethical development. If successful, it will make a difference from the past and overcome the remarkable repetitive quality of P scarcity debates.

Acknowledgments This special issue was realized thanks to the help and contributions of many people. I thank all authors who submitted their papers to be considered for the special issue. I also acknowledge the efforts by all reviewers and the editorial office for their support. Finally, I thank the Editor-in-Chief James Bennett for the invitation to organize an issue

Editorial

on sustainable phosphorus and for his valuable support throughout the process. References Fowler TP. History, Development, Status and Opportunities for Kiln Phosphoric Acid. International Fertilizer Society 2014; Proceedings 744. Ulrich, A.E., Frossard, E., 2014. On the history of a reoccurring concept: phosphorus scarcity. Sci. Total Environ. 490, 694–707.

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Andrea E. Ulrich Guest Editor Federal Office for Agriculture FOAG, Switzerland E-mail address: [email protected]. 2 October 2015

Taking Stock: Phosphorus Supply from Natural and Anthropogenic Pools in the 21st Century.

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