Take action to solve the phosphorus problem

September 14, 2021

ASU experts discuss the effectiveness and sustainability of agricultural fertilizers

Food production depends on phosphorus. It is an essential nutrient for crops of all kinds. And while commercial agriculture has grown over the past 70 years to feed a growing world population, phosphate rock mining has also grown to produce fertilizers.

Unfortunately, the application of these fertilizers is very inefficient. Only 20% of the phosphorus dumped in fields is taken up by plant roots and transported through the food chain. The rest is chemically locked away in the soil or dumped into canals, rivers, lakes and estuaries where agricultural irrigation eventually drains. This build-up in aquatic systems gradually causes eutrophication or the growth of harmful algal blooms that kill fish and other marine life.

“It’s a badIn planning and politics, a perverse problem is one that is difficult or impossible to solve due to incomplete, conflicting, and changing demands that are often difficult to recognize. Source: Wikipedia. problem, ”said Paul Westerhoff, Regents professor of civil, environmental and sustainable engineering at the Ira A. Fulton Schools of Engineering at Arizona State University. “At one level, it’s an environmental pollution problem. But it is also a question of the cost of the food. Simply reducing the use of phosphorus in fertilizers could decrease crop yields and increase the price of almost anything in the supermarket.

Westerhoff says reliance on mined phosphates is also a national security concern. Although the United States has significant reserves of phosphate rock in Florida and North Carolina, the current mining trajectory could deplete them within a generation. Most of the world’s rock phosphate reserves are found outside North America, and primarily in Morocco, making international relations a factor in long-term food production.

To address the complex ecological, economic and socio-political challenges associated with the rapidly expanding use of mined phosphorus in agriculture, the National Science Foundation has announced the establishment of a major new research center.

The Science and Technology Center for the Sustainability of Phosphorus (STEPS) brings together an interdisciplinary team of experts to pursue a “25 out of 25” vision. They seek to reduce human dependence on extracted phosphorus by 25% and also reduce current losses of phosphorus to soils and water resources by 25% over the next 25 years.

“Phosphorus is used in a very linear system right now. There is no recycling, ”said Jacob Jones, distinguished professor of materials science and engineering at North Carolina State University and director of the STEPS Center. “So our goal is to enable and encourage the recovery and reuse of phosphorus. We want to increase the circularity of phosphorus flows in the United States and around the world.

Funded by an initial grant of $ 25 million over five years and headquartered at North Carolina State University, the STEPS Center involves faculty, staff, and students from eight other partner institutions across the country, including ‘KNEW.

“Moving towards greater sustainability with this problem requires research on convergence,” said Westerhoff, who is deputy co-director of the STEPS Center as well as the Fulton chair of environmental engineering at the School of Sustainable Engineering and the Built Environment. , one of seven Fulton schools at ASU.

This convergence means harnessing the knowledge and skills of researchers and practitioners in multiple disciplines operating at very different scales – from molecular chemistry to human psychology to industrial economics.

“At the level of basic science, for example, we know very little about the structure and nature of phosphorus in soils. We need to understand how it interacts with enzymes and how they might make it more bioavailable to plants, ”Westerhoff said. “It is estimated that 30 to 40% of all phosphorus that has ever been applied to agricultural fields is still found in the soil at the root zone of the crops we are growing. It is a significant untapped resource.

The evaluation of new materials, technologies, processes and practices developed by the STEPS Center will be done primarily in three field test areas. Work on rural ecosystems will take place at an agricultural research station in eastern North Carolina. Aquatic ecosystem research will take place at sites in central and southern Florida. Work on the urban ecosystem will be done through the ASU Central Arizona-Phoenix Long-Term Ecological Research Program, or CAP LTER.

Operating within the University’s Global Institute of Sustainability and Innovation, CAP LTER studies urban socio-ecological systems. The relevance of this work for STEPS highlights the fact that meeting the phosphorus challenge is not only a question of agricultural efficiency.

“In Phoenix, the monsoons scatter a lot of fertilizer from our parks and yards. Where is it going and how can we get it back? Said Westerhoff. “In addition, there is a lot of food waste in all major metropolitan areas. How could we start to reuse the phosphorus from this biomass? “

Urban sanitation systems also offer the potential for phosphorus recovery. Processing human urine to produce fertilizer for the alfalfa fields that feed dairy cows may seem extreme, but farmers have applied animal manure to the soil for millennia.

Changing the paradigm and embracing new perspectives will be necessary to improve the sustainability of phosphorus in our food system.

Along with Westerhoff, a diverse team of other ASU experts will play key roles for the new STEPS center:

  • Christopher Muhich, assistant professor of chemical engineering at Fulton Schools, will be part of the STEPS Theme 1 team, which is research into atomic and molecular scale materials for capturing phosphorus. Westerhoff will also support the work of this theme.
  • Treavor Boyer, Associate Professor of Environmental Engineering at Fulton Schools and Senior Sustainability Scientist for ASU’s Global Institute for Sustainability and Innovation, will co-lead the Theme 2-focused team at STEPS, which Applies Material Discovery from Theme 1 to advancing technologies and techniques in the laboratory, greenhouse and field. His team will seek to trap and reuse nutrients in animal and human urine to create the fertilizers of the future.
  • Bruce Rittmann, Professor of Environmental Engineering at Fulton Schools and Director of ASU’s Biodesign Swette Center for Environmental Biotechnology, is also working on Theme 2. He will explore technologies that scavenge phosphorus as well as energy and others. vital resources from municipal and industrial wastewater.
  • Rebecca Muenich, Assistant Professor of Civil, Environmental and Sustainable Engineering at Fulton Schools, will co-lead the Theme 3 team at STEPS, which focuses on socio-economic and political practices that will support the achievement of the dual purpose. reducing phosphate extraction and stopping losses to the environment. James Elser, professor-researcher at ASU’s School of Life Sciences and director of the university’s Sustainable Phosphorus Alliance, also supports the work of this theme, which has helped inspire STEPS.
  • Matthew Scholz, Senior Sustainability Scientist for ASU’s Global Institute of Sustainability and Innovation as well as Senior Project Manager for ASU’s Rob and Melani Walton Sustainability Solutions Service, will co-lead the knowledge transfer team at ASU. STEPS, which aims to promote rapid and wide adoption of the solutions developed by the center. Elser will also advise the work of this team.

“We believe this is the biggest investment ever in phosphorus sustainability,” said Scholz. “The entire global food system would collapse without phosphorus, but it pollutes our waters and causes climate change in major ways. “

In addition to North Carolina State University and ASU, STEPS partner institutions are Appalachian State University, University of Florida, University of Illinois, Marquette University, the Joint School of Nanoscience and Nanoengineering operated by North Carolina Agricultural and Technical State University and the University of North Carolina Greensboro and the Research Triangle Institute, known as RTI International.

“We need everyone involved to help us develop an understanding of our best opportunities,” said Jones of North Carolina State University. “Maybe a particular material is only useful at a certain concentration, or a particular technique can only be used in certain soils or rivers. We need to figure out how to deploy our talents and tools to recover phosphorus as efficiently as possible and achieve this “25 out of 25” target.

Work on the new STEPS center officially begins on October 1.

Top image: Most of the phosphorus applied to crops as fertilizer is lost in the soil or as runoff to nearby canals, rivers, lakes and estuaries. This inefficiency poses environmental, economic and even national security challenges. Thus, ASU is working with a new national science and technology center focused on solving these problems and reducing agricultural dependence on phosphorus extracted from the earth. Photo by Erika Gronek / ASU

Science Editor, Ira A. Fulton Schools of Engineering

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