Perspectives for reducing “legacy phosphorus” in agricultural soils

2 February 2022, 14h – 17h CET

The webinar will discuss:
i) relationships between draw-down of soil P and crop productivity
ii) relationships between draw-down of soil P and diffuse P losses from agricultural soils

This ESPP webinar will follow on from the SPA (USA) webinar “A Legacy of Phosphorus”, 30^th September 2021, 18h-19h30 CEST and from the Frontiers in Earth Science special on ‘Legacy Phosphorus’ summarised in ESPP eNews n°56

A SCOPE Newsletter Special Issue will summarise this ESPP webinar and will also include selected further abstracts submitted as well as a c. 20 relevant recent scientific publications.

14h00 – 14h30 (4 x 5 min + 10 mins discussion)
Opening: What do we mean by “legacy P”?
Chair: Christiana Staudinger, Jakob Santner, University of Natural Resources and Life Sciences, Austria

• Phil Haygarth, Lancaster University, UK - European perspective
• Andrew Sharpley, University of Arkansas, USA: Phosphorus Legacies: Redefining the scientific, economic, and policy nexus to mitigate future water resource impairment
• Achim Dobermann, IFA (International Fertilizer Association) – Industry perspective
• Rich McDowell, AgResearch: New Zealand perspective: predicting soil P changes if fertiliser use is stopped, agronomic and environmental targets

14h30 – 15h00 (5 x 4 min + 10 mins discussion)
Europe: impacts of drawing down legacy P on crop yields (long-term trials)
Chair: Kasper Reitzel, University of Southern Denmark

• Inge Regelink, Wageningen University Research, Netherlands: 17 years trials on grassland in The Netherlands
• Debby Van Rotterdam, Nutrient Management Institute, Netherlands - Legacy soil P: a mass balance approach in a 10- year mining experiment
• Agnieszka Rutkowska, State Research Institute for Soil Science and Plant Cultivation, Poland - Long term effect of unbalanced fertilization with phosphorus and nitrogen – a case study for Poland
• Sabina Braun, Swedish University for Agricultural Sciences, Sweden - Grain yields and soil P changes from >50 years of soil fertility field experiments
• Vladimir Nosov, PhosAgro, Russia - Sustainable crop production: decreasing phosphorus rates or splitting phosphorus application?

15h00 – 15h40 (8 x 3 min + 15 mins discussion)
Worldwide: legacy P, draw down, soil phosphorus
Chair: Steve Hallam, International Fertiliser Society

• Yu Gu, Wageningen University Research, Netherlands - Potential of soil phosphorus saturation index for evaluating crop yield and runoff risks
• Amy Shober, University of Delaware, USA - Corn and soybean yield across continuum of soil test phosphorus concentrations under long-term drawdown
• Emileigh Lucas – University of Maryland, USA - Lessons from manure-applied “legacy-P” drawdown in the mid-Atlantic coastal plain, USA
• Andrew Margenot, Maria Rotham, University of Illinois, USA - Legacy phosphorus drawdown at decadal to centennial scales in the U.S. Maize Belt
• Tiequan Zhang, Harrow R&D Centre Agi-Food Canada - Legacy phosphorus in soils sustained crop yields with reduced soil phosphorus loss for 14 years
• Barbara Cade-Menun, Agriculture and Agri-Food Canada - Soil phosphorus concentrations and wheat yields in a long-term fertilization study in Saskatchewan
• Paulo Pavinato, University of Sao Paulo, Brazil - Legacy P availability in Brazilian tropical soils for sustainable crop production

15h40 – 15h50 – break

15h50 – 16h20 (3 x 5 min, 10 min questions)
How does legacy P or draw-down impact losses to surface waters?

• Victoria Barcala, Deltares, The Netherlands: Processes controlling the flux of legacy phosphorus to surface waters at the farm scale
• Juliane Hirte, Agroscope, Switzerland - Reducing legacy soil phosphorus to tolerable levels for surface waters: A case study from Switzerland
• Sarah Stackpoole, US Geological Survey - Legacy and contemporary phosphorus contributions influence river water quality trends in the conterminous United States

16h20 – 17h00 (8 x 2 minutes, 20 mins discussion)
Conclusions from panel of experts
Chair: Steve Hallam, International Fertiliser Society

Panellists are invited to draw conclusions (and future perspectives), 2 min each, and also to monitor and animate the discussion in the Chat and in the above questions/discussion sessions.

• Jim Elser, Sustainable Phosphorus Alliance, Arizona State University, USA
• Luke Gatiboni, North Carolina State University, USA
• Marzena Smol, Polish Academy of Sciences, Poland
• Antonio Delgado, University of Seville, Spain
• Kari Ylivainio, Natural Resources Institute (LUKE), Finland
• Leonardus Vergutz, Mohammed VI Polytechnic University, Morocco

The programme is available in pdf here.

Video recording is available here

Book of abstracts is available here

Edited CHAT transcript is available here