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Climate predictions in temperate regions suggest that autumn and winter rainfall events are likely to increase in both duration and total amounts of precipitation. This is likely to increase the spatial and temporal occurrence of reducing environments in soils. Unlike more typical aerobic soil systems, these anaerobic systems facilitate conditions in which alternative oxidation states of vital elements needed for a healthy soil system present themselves. This therefore introduces the likelihood of the establishment of alternative chemical equilibria, involving lower oxidation state compounds, including the element P, which in recent years has gained attention as being an immediate element of concern. Currently. There is a lack of information about the abundance, availability and utilisation of such nutrient sources within biological systems; and further to that, the chemical processes that control mobilisation and immobilisation of reduced chemical species. This research investigates the reduced phosphorus compound, N-(phosphonomethyl) glycine, also known as glyphosate and its breakdown product Aminomethyl phosphonic acid (AMPA). Both compounds are phosphonate compounds, a reduced group of phosphorus compounds in the oxidation state +3. This research was conducted to better understand their biochemistry and dynamics within the soil system as soil contaminants in agricultural soils. An extensive literature review was conducted, gathering existing data to investigate the multiple pathways and transformations that the reduced P compounds and groups likely utilise in the soil system. A conceptual model was produced, demonstrating this and highlighting one of the largest agricultural inputs being from the reduced P group, the phosphonates. A study was undertaken to asses which soil treatments phosphonate compounds are most likely to be found in, with 31P NMR data demonstrating that grassland and wetland sites have a higher likelihood to contain phosphonate compounds, bot

Phosphorus (P) is a key limiting factor in crop growth and essential for agriculture. As plant uptake of P is inefficient, it is commonly applied to maintain crop yields leading to a range of negative environmental issues when applied in excess. Additionally, P in mineral fertilisers is derived from mined rock phosphate, which is a finite resource that needs to be sustainably managed in order to maintain food security in the long-term. Phosphatase activity is one of several mechanistic responses to P deficiency in the plant-soil system, enabling the mineralization of organic P to increase P availability for both plants and soil organisms. In this study we address the need to further understanding of the role of phosphatase enzyme activity in P acquisition in agricultural settings, using a systematic review of the literature and subsequent meta-analysis. We find that monoesterase activity is inhibited by availability of inorganic P (−23%, −39.8 - -2.2%) yet is enhanced by the availability of organic P (+74%, 8.4–232.1%). This indicates that phosphatase enzyme activity is important in P deficient agricultural systems, yet that the availability of organic P is more important in determining phosphatase activity than the level of P deficiency. We also investigated the role of other factors such as nitrogen addition, pH of growth substrate and changes in plant composition and physiology but, none of these factors explained significant variance in the data. We highlight need for consistent recording and reporting of additional variables in association with phosphatase enzyme assay data, which is required to enable quantification of the potential utilisation of organic P resources in agriculture, and the contribution of phosphatase activity to P acquisition in both agricultural and semi-natural ecosystems.

Recycling phosphorus-rich organic wastes and manures is critical for phosphorus sustainability and a transition to a more circular economy for phosphorus. Beyond agronomic benefits, the win-wins are numerous, with benefits to society, environment, economy, and business growth. However, to significantly increase phosphorus recycling, education, awareness-raising, investment in technology and infrastructure, and policy support are urgently needed.