Opportunities for mobilizing recalcitrant phosphorus from agricultural soils: a review

Abstract

Background Phosphorus (P) fertilizer is usually applied in excess of plant requirement and accumulates in soils due to its strong adsorption, rapid precipitation and immobilisation into unavailable forms including organic moieties. As soils are complex and diverse chemical, biochemical and biological systems, strategies to access recalcitrant soil P are often inefficient, case specific and inconsistently applicable in different soils. Finding a near-universal or at least widely applicable solution to the inefficiency in agricultural P use by plants is an important unsolved problem that has been under investigation for more than half a century. Scope In this paper we critically review the strategies proposed for the remobilization of recalcitrant soil phosphorus for crops and pastures worldwide. We have additionally performed a meta-analysis of available soil 31 P-NMR data to establish the potential agronomic value of different stored P forms in agricultural soils. Conclusions Soil inorganic P stocks accounted on average for 1006 ± 115 kg ha −1 (57 ± 7%), while the monoester P pool accounted for 587 ± 32 kg ha −1 (33 ± 2%), indicating the huge potential for the future agronomic use of the soil legacy P. New impact driven research is needed in order to create solutions for the sustainable management of soil P stocks.

Contrasting P acquisition strategies of the bacterial communities associated with legume and grass in subtropical orchard soil

“…Soil C/P ratio can reflect the degree of P scarcity (Menezes-Blackburn et al, 2018). When compared with control soil, the C/P ratio was significantly increased in stylo soil but not affected in bahiagrass soil ( Fig.…”

Options for Improved Phosphorus Cycling and Use in Agriculture at the Field and Regional Scales

“…However the potential benefits depend on soil properties, including the amount and form of P in the soil, and the specific crop species combinations involved (Kamh et al, 1999; Cavigelli and Thien, 2003; Nuruzzaman et al, 2005; Arcand et al, 2010; Maltais‐Landry and Frossard, 2015; Pavinato et al, 2017; Doolette et al, 2019). As Menezes‐Blackburn et al (2018) discussed, plants with efficient P uptake mechanisms should be useful for mobilizing recalcitrant legacy P and helping make it available to the subsequent crop. Phosphorus mobilization by cover crops appears to result in greater relative yield increases in the subsequent crop when available soil Pi is low and where traits affecting P mobilization should be fully expressed; however, these benefits may be limited if total soil P is low (Hallama et al, 2018).…”

“…Critical improvements have been made via the promotion and implementation of the 4Rs; however, further reductions in fertilizer recommendations are likely possible by promoting PUE via strategic plant breeding programs and cropping system design (i.e., crop/cultivar selection, crop rotation, intercropping) and through managing for soil biological processes that can contribute to plant P uptake (Fig. 1) (Veneklaas et al, 2012; Bender et al, 2016; Menezes‐Blackburn et al, 2018). …”

Developmental plasticity ofBrachypodium distachyonin response to P deficiency: modulation by inoculation with phosphate-solubilizing bacteria

“…In industrialized countries, the excessive use of P fertilisers has led to an accumulation of P in agricultural soils, constituting a new source of P reserves known as “legacy soil P” (van Dijk et al 2016; Menezes-Blackburn et al 2018; Rowe et al 2016). In some regions, this accumulation has reached levels that generate an environmental risk of watercourse contamination and subsequent eutrophication (Haygarth et al 2014).…”

“…In some regions, this accumulation has reached levels that generate an environmental risk of watercourse contamination and subsequent eutrophication (Haygarth et al 2014). It has been estimated that the total soil P stock for arable and grassland soils represents 352 ± 26 years of agronomic P use, with orthophosphate and monoester (organic) phosphate accounting for the greatest proportion (study based on 258 different soils collected in Europe, Oceania and North America; Menezes-Blackburn et al 2018). However, this soil P reserve is unavailable to plants due to the capacity of many soils to fix P (Shen et al 2011).…”