Cycling of reduced phosphorus compounds in soil and potential impacts of climate change

Abstract

Soil phosphorus (P) remains an ever-increasing topic of importance, notably for its key role as a nutrient for driving food production but with parallel concerns over damaging water quality, all against a backdrop of uncertainty of long-term rock phosphate supplies. Soil is a key interface that holds P and regulates its onward flow to plants or leakage to waters. Often overlooked are a ubiquitous group of P compounds that exist in alternative oxidation states to that of phosphate (+5). Redox cycling, and the behaviour that chemically reduced P compounds exhibit in soils, introduces alternative routes of cycling P that may become more important as the soil system itself alters, especially due to the external pressures of climate change, bringing about critical dynamics in rainfall and runoff and also wetting and drying. All of these factors are known to affect soil redox potential and consequently the oxidation state of soil P. This review considers the chemically reduced species in the P cycle, exploring their sources and sinks, while considering their importance within the primary global biogeochemical cycling of P and how this may be impacted by climate change in the temperate climate of the northern hemisphere. Highlights• This paper addresses how climate change will affect soil phosphorus cycling.• This review is novel as it considers the reduced phosphorus forms when discussing P transfer in soils.• Climate change is likely to increase prevalence of reduced P and free phosphate in northern hemisphere temperate soils.• Phosphorus cycling relies partly on redox P processes. Their importance will increase as climate alters soils.

The Microbial Degradation of Natural and Anthropogenic Phosphonates

“…The majority of soil phosphonate studies have focused on environmental pollutants such as glyphosate, which is generally degraded via C-P lyase (discussed in Section 8), and so the study of substrate-specific pathways has been significantly neglected in this environment [125]. Better characterized is phosphonate synthesis, with one study suggesting that a diverse range of phosphonates are likely to be produced in soils [4].…”

Different mechanisms driving increasing abundance of microbial phosphorus cycling gene groups along an elevational gradient

“…( Takyu et al., 2003 ). Microorganisms drive P cycle by mineralizing organic P, immobilizing inorganic P, synthesizing new organic P, and affecting the solubility of P minerals in terrestrial ecosystems ( Willey et al., 2014 ; Kehler et al., 2021 ). Such P-cycling processes are mainly mediated by three microbial gene groups, i.e., genes involved in inorganic P-solubilization and organic P-mineralization, P-uptake and transport, and P-starvation response regulation ( Dai et al., 2020 ).…”