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Akram, U., Metson, G., Quttineh, N.-H. & Wennergren, U. (2018). Closing Pakistan’s yield gaps through nutrient recycling. Frontiers in Sustainable Food Systems, 1-14, Article ID 00024.
Open this publication in new window or tab >>Closing Pakistan’s yield gaps through nutrient recycling
2018 (English)In: Frontiers in Sustainable Food Systems, E-ISSN 2571-581X, p. 1-14, article id 00024Article in journal (Refereed) Published
Abstract [en]

Achieving food security will require closing yield gaps in many regions, including Pakistan. Although fertilizer subsidies have facilitated increased nitrogen (N) application rates, many staple crop yields have yet to reach their maximum potential. Considering that current animal manure and human excreta (bio-supply) recycling rates are low, there is substantial potential to increase the reuse of nutrients in bio-supply. We quantified 2010 crop N, phosphorus (P), and potassium (K) needs along with bio-supply nutrient availability for Pakistani districts, and compared these values to synthetic fertilizer use and costs. We found that synthetic fertilizer use combined with low bio-supply recycling resulted in a substantial gap between nutrient supply and P and K crop needs, which would cost 3 billion USD to fill with synthetic fertilizers. If all bio-supply was recycled, it could eliminate K synthetic fertilizer needs and decrease N synthetic fertilizer needs to 43% of what was purchased in 2010. Under a full recycling scenario, farmers would still require an additional 0.28 million tons of synthetic P fertilizers, costing 2.77 billion USD. However, it may not be prohibitively expensive to correct P deficiencies. Pakistan already spends this amount of money on fertilizers. If funds used for synthetic N were reallocated to synthetic P purchases in a full bio-supply recycling scenario, crop needs could be met. Most recycling could happen within districts, with only 6% of bio-supply requiring between-district transport when optimized to meet national N crop needs. Increased recycling in Pakistan could be a viable way to decrease yield gaps.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2018
National Category
Environmental Sciences
Identifiers
urn:nbn:se:liu:diva-148786 (URN)10.3389/fsufs.2018.00024 (DOI)000502077100001 ()
Available from: 2018-06-19 Created: 2018-06-19 Last updated: 2020-03-05Bibliographically approved
Nesme, T., Metson, G. & Bennett, E. M. (2018). Global phosphorus flows through agricultural trade. Global Environmental Change, 50, 133-141
Open this publication in new window or tab >>Global phosphorus flows through agricultural trade
2018 (English)In: Global Environmental Change, ISSN 0959-3780, E-ISSN 1872-9495, Vol. 50, p. 133-141Article in journal (Refereed) Published
Abstract [en]

The global phosphorus cycle has been transformed in recent decades through increased use of mineral phosphorus fertilizer in agriculture and losses to water bodies, leading to risks of fossil phosphorus resource depletion and freshwater eutrophication. By moving phosphorus resources across world regions, international trade of agricultural products (food, feed, fiber and fuel) may contribute to these changes in the global phosphorus cycle, including critical nutrient imbalances. However, we lack a comprehensive, quantitative understanding of the role of agricultural trade in the global phosphorus cycle. By combining detailed data on international trade and the phosphorus content of agricultural products, we demonstrate that phosphorus flows through trade increased nearly eight-fold from 0.4 Tg P/yr in 1961 to 3.0 Tg P/yr in 2011, leading to an increase in the fraction of phosphorus taken up by crops that is subsequently exported from 9% in 1961 to 20% in 2011. The P flows in traded agricultural products was equivalent to 27% of the P traded in mineral fertilizers in 2011. Agricultural P flows were mostly driven by trade of cereals, soybeans and feed-cakes, with 28% of global phosphorus traded in human food, 44% in animal feed and 28% in crops for other uses in 2011. We found a strong spatial pattern in traded phosphorus in agricultural products, with most flows originating from the Americas and ending in Western Europe and Asia, with large amounts of phosphorus moving through trade within Western Europe, in strong contrast with the pattern of the mineral P fertilizer trade. We demonstrate that international trade of agricultural products has affected the domestic phosphorus cycle within many countries, making phosphorus exporters susceptible to the volatility of the mineral phosphorus fertilizer market. Overall, these results highlight the importance of trade as key component of the global phosphorus cycle.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Phosphorus cycle; International trade; Global food security; Anthropocene
National Category
Social Sciences Interdisciplinary
Identifiers
urn:nbn:se:liu:diva-149741 (URN)10.1016/j.gloenvcha.2018.04.004 (DOI)000436223800011 ()
Note

Funding Agencies|Bordeaux Sciences Agro (Univ. Bordeaux); McGill School of Environment during TNs sabbatical; NSERC Discovery Grant

Available from: 2018-07-18 Created: 2018-07-18 Last updated: 2018-09-14
Metson, G., Powers, S. M., Hale, R. L., Sayles, J. S., Oberg, G., MacDonald, G. K., . . . Bouwman, A. F. (2018). Socio-environmental consideration of phosphorus flows in the urban sanitation chain of contrasting cities. Regional Environmental Change, 18(5), 1387-1401
Open this publication in new window or tab >>Socio-environmental consideration of phosphorus flows in the urban sanitation chain of contrasting cities
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2018 (English)In: Regional Environmental Change, ISSN 1436-3798, E-ISSN 1436-378X, Vol. 18, no 5, p. 1387-1401Article in journal (Refereed) Published
Abstract [en]

Understanding how cities can transform organic waste into a valuable resource is critical to urban sustainability. The capture and recycling of phosphorus (P), and other essential nutrients, from human excreta is particularly important as an alternative organic fertilizer source for agriculture. However, the complex set of socio-environmental factors influencing urban human excreta management is not yet sufficiently integrated into sustainable P research. Here, we synthesize information about the pathways P can take through urban sanitation systems along with barriers and facilitators to P recycling across cities. We examine five case study cities by using a sanitation chains approach: Accra, Ghana; Buenos Aires, Argentina; Beijing, China; Baltimore, USA; and London, England. Our cross-city comparison shows that London and Baltimore recycle a larger percentage of P from human excreta back to agricultural lands than other cities, and that there is a large diversity in socio-environmental factors that affect the patterns of recycling observed across cities. Our research highlights conditions that may be "necessary but not sufficient" for P recycling, including access to capital resources. Path dependencies of large sanitation infrastructure investments in the Global North contrast with rapidly urbanizing cities in the Global South, which present opportunities for alternative sanitation development pathways. Understanding such city-specific social and environmental barriers to P recycling options could help address multiple interacting societal objectives related to sanitation and provide options for satisfying global agricultural nutrient demand.

Place, publisher, year, edition, pages
Heildelberg: Springer, 2018
Keywords
Phosphorus; Sanitation; Sustainability; Socio-environmental factors; Urban
National Category
Human Geography
Identifiers
urn:nbn:se:liu:diva-148377 (URN)10.1007/s10113-017-1257-7 (DOI)000432987600013 ()
Note

Funding Agencies|National Socio-Environmental Synthesis Center (SESYNC) from the National Science Foundation [DBI-1052875]

Available from: 2018-06-15 Created: 2018-06-15 Last updated: 2018-09-14Bibliographically approved
Metson, G., Lin, J., Harrison, J. & Compton, J. (2017). Linking 2012 terrestrial P inputs to riverine export from watersheds across the United States. Water Research, 124, 177-191
Open this publication in new window or tab >>Linking 2012 terrestrial P inputs to riverine export from watersheds across the United States
2017 (English)In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 124, p. 177-191Article in journal (Refereed) Published
Abstract [en]

Humans have greatly accelerated phosphorus (P) flows from land to aquatic ecosystems, causing eutrophication, harmful algal blooms, and hypoxia. A variety of statistical and mechanistic models have been used to explore the relationship between P management on land and P losses to waterways, but our ability to predict P losses from watersheds often relies on small scale catchment studies, where detailed measurements can be made, or global scale models that that are often too coarse-scaled to be used directly in the management decision-making process. Here we constructed spatially explicit datasets of terrestrial P inputs and outputs across the conterminous U.S. (CONUS) for 2012. We use this dataset to improve understanding of P sources and balances at the national scale and to investigate whether well-standardized input data at the continental scale can be used to improve predictions of hydrologic P export from watersheds across the U.S. We estimate that in 2012 agricultural lands received 0.19 Tg more P as fertilizer and confined manure than was harvested in major crops. Approximately 0.06 Tg P was lost to waterways as sewage and detergent nationally based on per capita loads in 2012. We compared two approaches for calculating non-agricultural P waste export to waterways, and found that estimates based on per capita P loads from sewage and detergent were 50% greater than Discharge Monitoring Report Pollutant Loading Tool. This suggests that the tool is likely underestimating P export in waste the CONUS scale. TP and DIP concentrations and TP yields were generally correlated more strongly with runoff than with P inputs or P balances, but even the relationships between runoff and P export were weak. Including P inputs as independent variables increased the predictive capacity of the best-fit models by at least 20%, but together inputs and runoff explained 40% of the variance in P concentration and 46–54% of the variance in P yield. By developing and applying a high-resolution P budget for the CONUS this study confirms that both hydrology and P inputs and sinks play important roles in aquatic P loading across a wide range of environments.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Phosphorus, Water quality, Agriculture, Sewage
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:liu:diva-151243 (URN)10.1016/j.watres.2017.07.037 (DOI)
Available from: 2018-09-13 Created: 2018-09-13 Last updated: 2018-09-14Bibliographically approved
Cordell, D., Metson, G., Iwaniec, D., Bui, T., Childers, D., Dao, N., . . . Tilley, E. (2017). Transforming Cities: Securing food and clean waterways through phosphorus governance. In: Dena Fam, Jane Palmer, Chris Riedy, Cynthia Mitchell (Ed.), Transdiciplinary Research and Practice for Sustainability Outcomes: (pp. 139-154). Routledge
Open this publication in new window or tab >>Transforming Cities: Securing food and clean waterways through phosphorus governance
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2017 (English)In: Transdiciplinary Research and Practice for Sustainability Outcomes / [ed] Dena Fam, Jane Palmer, Chris Riedy, Cynthia Mitchell, Routledge, 2017, p. 139-154Chapter in book (Refereed)
Abstract [en]

As an essential input to crop growth via soil reserves or fertilizer, phosphorus underpins global food security. Without phosphorus, food could not be produced, yet phosphorus is mined from fi nite reserves, most of which are controlled by only a few countries1 (UNEP 2011; Jasinski 2015; Cordell and White 2014). Fertilizer prices are likely to increase as fi nite reserves become critically scarce. Globally, a billion farmers and their families cannot access fertilizer markets and many rely on phosphorus-defi cient soils that produce low crop yields (IFPRI 2003). Moreover, mismanagement along the phosphorus supply chain from mine to fi eld to fork has resulted in massive losses and waste, which largely ends up in waterways, causing nutrient pollution and algal blooms (Bennett, Carpenter and Caraco 2001). The global phosphorus challenge is inherently complex; it is as much about international relations as farm soil fertility. It transcends disciplines, sectors, and scales – from geopolitics to ecology to nutrition. In this chapter, we describe and refl ect upon a new project using a novel transdisciplinary approach to address this phosphorus challenge.

Place, publisher, year, edition, pages
Routledge, 2017
Series
Routledge Studies in Sustainability
National Category
Social Sciences Interdisciplinary
Identifiers
urn:nbn:se:liu:diva-151255 (URN)9781138625730 (ISBN)9781138119703 (ISBN)9781315652184 (ISBN)
Available from: 2018-09-14 Created: 2018-09-14 Last updated: 2018-09-14Bibliographically approved
Metson, G., MacDonald, G., Haberman, D., Nesme, T. & Bennett, E. (2016). Feeding the Corn Belt: Opportunities for phosphorus recycling in U.S. agriculture. Science of the Total Environment, 542(Part B), 1117-1126
Open this publication in new window or tab >>Feeding the Corn Belt: Opportunities for phosphorus recycling in U.S. agriculture
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2016 (English)In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 542, no Part B, p. 1117-1126Article in journal (Refereed) Published
Abstract [en]

The supply of phosphorus (P) is a critical concern for food security. Concentrated mineral P deposits have been the source of almost all new P entering the biosphere. However, this resource is often used inefficiently, raising concerns about both nutrient pollution and future access to fertilizers. One solution to both of these problems is to enhance our ability to capture and recycle P from waste streams. However, the efficacy of doing this has not been rigorously explored. Here, we examine the potential for recycling major P sources in the United States to supply the necessary P for domestic corn (maize) production. Using 2002 population and agricultural census data, we examine the distribution of three key recyclable P sources (human food waste, human excreta, and animal manure) and P demand from grain and silage corn across the country to determine the distance P would need to be transported from sources to replenish P removed from soils in harvested corn plants. We find that domestic recyclable P sources, predominantly from animal manures, could meet national corn production P demands with no additional fertilizer inputs. In fact, only 37% of U.S. sources of recyclable P would be required to meet all P demand from U.S. corn harvested annually. Seventy-four percent of corn P demand could be met by recyclable P sources in the same county. Surplus recyclable P sources within-counties would then need to travel on average 302 km to meet the largest demand in and around the center of the ‘Corn Belt’ region where ~ 50% of national corn P demand is located. We find that distances between recyclable sources and crop demands are surprisingly short for most of the country, and that this recycling potential is mostly related to manure. This information can help direct where recycling efforts should be most-effectively directed.

Place, publisher, year, edition, pages
Elsevier, 2016
National Category
Environmental Sciences related to Agriculture and Land-use
Identifiers
urn:nbn:se:liu:diva-151247 (URN)10.1016/j.scitotenv.2015.08.047 (DOI)
Available from: 2018-09-13 Created: 2018-09-13 Last updated: 2018-09-14Bibliographically approved
Iwaniec, D., Metson, G. & Cordell, D. (2016). P-FUTURES: Towards urban food & water security through collaborative design and impact. Current Opinion in Environmental Sustainability, 20, 1-7
Open this publication in new window or tab >>P-FUTURES: Towards urban food & water security through collaborative design and impact
2016 (English)In: Current Opinion in Environmental Sustainability, ISSN 1877-3435, E-ISSN 1877-3443, Vol. 20, p. 1-7Article in journal (Refereed) Published
Abstract [en]

Phosphorus is essential to food production, but current management practices fail to ensure equitable access to farmers globally and often results in polluted waterways. There is a lack of local and global governance mechanisms to ensure phosphorus is sustainably managed. The P-FUTURES research initiative aims to address this gap by working with stakeholders to explore visions and pathways of social transformation towards food and water security. In the seed phase of the project, academic, civil, industry, and municipal stakeholders interacted as partners in Blantyre (Malawi), Hanoi (Vietnam), Sydney (Australia), and Phoenix (USA) to collaboratively develop a full proposal and build capacity for transformational change. The article offers guidance on the opportunities and challenges of co-developing a research approach and proposal in a transdisciplinary, international setting.

Place, publisher, year, edition, pages
Elsevier, 2016
National Category
Social Sciences Interdisciplinary
Identifiers
urn:nbn:se:liu:diva-151245 (URN)10.1016/j.cosust.2016.03.001 (DOI)
Available from: 2018-09-13 Created: 2018-09-13 Last updated: 2018-09-14Bibliographically approved
Metson, G., Cordell, D. & Ridoutt, B. (2016). Potential impact of dietary choices on phosphorus recycling and global phosphorus footprints: the case of the average Australian city. Frontiers in Nutrition, 3, 1-7, Article ID 35.
Open this publication in new window or tab >>Potential impact of dietary choices on phosphorus recycling and global phosphorus footprints: the case of the average Australian city
2016 (English)In: Frontiers in Nutrition, E-ISSN 2296-861X, Vol. 3, p. 1-7, article id 35Article in journal (Refereed) Published
Abstract [en]

Changes in human diets, population increases, farming practices, and globalized food chains have led to dramatic increases in the demand for phosphorus fertilizers. Long-term food security and water quality are, however, threatened by such increased phosphorus consumption, because the world’s main source, phosphate rock, is an increasingly scarce resource. At the same time, losses of phosphorus from farms and cities have caused widespread water pollution. As one of the major factors contributing to increased phosphorus demand, dietary choices can play a key role in changing our resource consumption pathway. Importantly, the effects of dietary choices on phosphorus management are twofold: First, dietary choices affect a person or region’s “phosphorus footprint” – the magnitude of mined phosphate required to meet food demand. Second, dietary choices affect the magnitude of phosphorus content in human excreta and hence the recycling- and pollution-potential of phosphorus in sanitation systems. When considering options and impacts of interventions at the city scale (e.g., potential for recycling), dietary changes may be undervalued as a solution toward phosphorus sustainability. For example, in an average Australian city, a vegetable-based diet could marginally increase phosphorus in human excreta (an 8% increase). However, such a shift could simultaneously dramatically decrease the mined phosphate required to meet the city resident’s annual food demand by 72%. Taking a multi-scalar perspective is therefore key to fully exploring dietary choices as one of the tools for sustainable phosphorus management.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2016
National Category
Environmental Sciences
Identifiers
urn:nbn:se:liu:diva-151244 (URN)10.3389/fnut.2016.00035 (DOI)
Available from: 2018-09-13 Created: 2018-09-13 Last updated: 2018-09-14
Nesme, T., Roques, S., Metson, G. & Bennett, E. (2016). The surprisingly small but increasing role of international agricultural trade on the European Union’s dependence on mineral phosphorus fertiliser. Environmental Research Letters, 11, Article ID 025003.
Open this publication in new window or tab >>The surprisingly small but increasing role of international agricultural trade on the European Union’s dependence on mineral phosphorus fertiliser
2016 (English)In: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 11, article id 025003Article in journal (Refereed) Published
Abstract [en]

Phosphorus (P) is subject to global management challenges due to its importance to both food security and water quality. The European Union (EU) has promoted policies to limit fertiliser over-application and protect water quality for more than 20 years, helping to reduce European P use. Over this time period, the EU has, however, become more reliant on imported agricultural products. These imported products require fertiliser to be used in distant countries to grow crops that will ultimately feed European people and livestock. As such, these imports represent a displacement of European P demand, possibly allowing Europe to decrease its apparent P footprint by moving P use to locations outside the EU. We investigated the effect of EU imports on the European P fertiliser footprint to better understand whether the EU's decrease in fertiliser use over time resulted from P demand being 'outsourced' to other countries or whether it truly represented a decline in P demand. To do this, we quantified the 'virtual P flow' defined as the amount of mineral P fertiliser applied to agricultural soils in non-EU countries to support agricultural product imports to the EU. We found that the EU imported a virtual P flow of 0.55 Tg P/yr in 1995 that, surprisingly, decreased to 0.50 Tg P/yr in 2009. These results were contrary to our hypothesis that trade increases would be used to help the EU reduce its domestic P fertiliser use by outsourcing its P footprint abroad. Still, the contribution of virtual P flows to the total P footprint of the EU has increased by 40% from 1995 to 2009 due to a dramatic decrease in domestic P fertiliser use in Europe: in 1995, virtual P was equivalent to 32% of the P used as fertiliser domestically to support domestic consumption but jumped to 53% in 2009. Soybean and palm tree products from South America and South East Asia contributed most to the virtual P flow. These results demonstrate that, although policies in the EU have successfully decreased the domestic dependence on mineral P fertiliser, in order to continue to limit global potential mineral P supply depletion and consequences of P losses to waterways the EU may have to think about its trading partners.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2016
National Category
Environmental Sciences related to Agriculture and Land-use
Identifiers
urn:nbn:se:liu:diva-151246 (URN)10.1088/1748-9326/11/2/025003 (DOI)
Available from: 2018-09-13 Created: 2018-09-13 Last updated: 2018-10-05Bibliographically approved
Metson, G. & Bennett, E. (2015). Facilitators & barriers to organic waste and phosphorus re-use in Montreal. Elementa Science of the Anthropocene, 3, 1-13, Article ID 000070.
Open this publication in new window or tab >>Facilitators & barriers to organic waste and phosphorus re-use in Montreal
2015 (English)In: Elementa Science of the Anthropocene, E-ISSN 2325-1026, Vol. 3, p. 1-13, article id 000070Article in journal (Refereed) Published
Abstract [en]

Cities have the capacity to play a key role in resource and pollution management through their decisions about organic waste. Often overlooked, but nevertheless essential, is the role that cities can play in increasing phosphorus (P) recycling because cities are consumers of large amounts of P-dense food and producers of vast amounts of P-rich waste. Most cities do not take advantage of this potential, seeing P as simply another part of organic waste to be disposed of elsewhere. For example, in Montreal, Canada, only 6% of P in waste is currently recycled. We used semi-structured interviews with key stakeholders (19), participant observation (over 1.5 years), and document review to identify key barriers and facilitators for Montreal to achieve a high level of organic waste recycling through composting. We found that a provincial law mandating 100% recycling of organic matter has great potential to facilitate increased P recycling. However, lack of a shared vision about the role of government, private sector, and citizens in producing high quality compost from waste products is a barrier that inhibits this potential. Cultural inertia, lack of knowledge, and lack of infrastructure also act as barriers to increasing composting in Montreal. Urban agriculture could be a means to overcome some of these barriers as it currently benefits from strong citizen support and is both a consumer and producer of compost. However limited access to potential garden space and training and diversity in desired fertilizer qualities among gardeners somewhat limit this potential. Investing in increasing social capital, and specifically in connecting urban agriculture to waste management objectives, and in linking key stakeholders to co-create shared visions about how to produce high quality compost may act as a stepping stone towards increasing Montreal citizens’ knowledge about, and support for, increasing organic waste and thus P recycling.

Place, publisher, year, edition, pages
University of California Press, 2015
National Category
Other Social Sciences not elsewhere specified
Identifiers
urn:nbn:se:liu:diva-151250 (URN)10.12952/journal.elementa.000070 (DOI)
Available from: 2018-09-14 Created: 2018-09-14 Last updated: 2018-10-08Bibliographically approved
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