Reviews and syntheses: Ironing out wrinkles in the soil phosphorus cycling paradigm

• Main Authors: C. A. McConnell, J. P. Kaye, A. R. Kemanian
• Format: Article
• Language: English
• Published: Copernicus Publications 2020-11-01
• Series: Biogeosciences
• Online Access: https://bg.copernicus.org/articles/17/5309/2020/bg-17-5309-2020.pdf

<p>Soil phosphorus (P) management remains a critical challenge for agriculture worldwide, and yet we are still unable to predict soil P dynamics as confidently as that of carbon (C) or nitrogen (N). This is due to both the complexity of inorganic P (<span class="inline-formula">P_i</span>) and organic P (<span class="inline-formula">P_o</span>) cycling and the methodological constraints that have limited our ability to trace P dynamics in the soil–plant system. In this review, we describe the challenges for building parsimonious, accurate, and useful biogeochemical models that represent P dynamics and explore the potential of new techniques to usher P biogeochemistry research and modeling forward. We conclude that research efforts should focus on the following: (1) updating the McGill and Cole (1981) model of <span class="inline-formula">P_o</span> mineralization by clarifying the role and prevalence of biochemical and biological <span class="inline-formula">P_o</span> mineralization, which we suggest are not mutually exclusive and may co-occur along a continuum of <span class="inline-formula">P_o</span> substrate stoichiometry; (2) further understanding the dynamics of phytate, a six C compound that can regulate the poorly understood stoichiometry of soil P; (3) exploring the effects of C and <span class="inline-formula">P_o</span> saturation on P sorption and <span class="inline-formula">P_o</span> mineralization; and (4) resolving discrepancies between hypotheses about P cycling and the methods used to test these hypotheses.</p>