Global patterns and drivers of soil total phosphorus concentration

Abstract

Abstract. Soil represents the largest phosphorus (P) stock in terrestrial ecosystems. Determining the amount of soil P is a critical first step in identifying sites where ecosystem functioning is potentially limited by soil P availability. However, global patterns and predictors of soil total P concentration remain poorly understood. To address this knowledge gap, we constructed a database of total P concentration of 5275 globally distributed (semi-)natural soils from 761 published studies. We quantified the relative importance of 13 soil-forming variables in predicting soil total P concentration and then made further predictions at the global scale using a random forest approach. Soil total P concentration varied significantly among parent material types, soil orders, biomes, and continents and ranged widely from 1.4 to 9630.0 (median 430.0 and mean 570.0) mg kg−1 across the globe. About two-thirds (65 %) of the global variation was accounted for by the 13 variables that we selected, among which soil organic carbon concentration, parent material, mean annual temperature, and soil sand content were the most important ones. While predicted soil total P concentrations increased significantly with latitude, they varied largely among regions with similar latitudes due to regional differences in parent material, topography, and/or climate conditions. Soil P stocks (excluding Antarctica) were estimated to be 26.8 ± 3.1 (mean ± standard deviation) Pg and 62.2 ± 8.9 Pg (1 Pg = 1 × 1015 g) in the topsoil (0–30 cm) and subsoil (30–100 cm), respectively. Our global map of soil total P concentration as well as the underlying drivers of soil total P concentration can be used to constraint Earth system models that represent the P cycle and to inform quantification of global soil P availability. Raw datasets and global maps generated in this study are available at https://doi.org/10.6084/m9.figshare.14583375 (He et al., 2021).

Three‐dimensional mapping of carbon, nitrogen, and phosphorus in soil microbial biomass and their stoichiometry at the global scale

“…In cases where studies did not report a given predictor, we extracted the missing data from global data maps or satellite remote sensing data according to the geographic coordinates of the measurement sites. In addition to the above predictors, we also considered soil depth as a covariate to predict the concentration of soil microbial biomass at different soil depths (He et al, 2021;Hengl et al, 2017). Furthermore, five climate/vegetation parameters from the four seasons were used to predict soil MBC for each season.…”

Global patterns and drivers of phosphorus pools in natural soils

“…P supplied by the soil plays a vital role in determining the structures, functions, and processes in terrestrial ecosystems (Peltzer et al, 2010;Wardle et al, 2004). For example, soil P availability imposes a major constraint on plant productivity in terrestrial ecosystems worldwide (Augusto et al, 2017;Ellsworth et al, 2022;Elser et al, 2007;Hou et al, 2020;Hou et al, 2021) and affects modeled projections of terrestrial carbon cycle responses to climate change and increasing atmospheric carbon dioxide concentrations (Cunha et al, 2022;Fleischer et al, 2019;Goll et al, 2012). The size of soil P stocks is large compared to annual plant P requirements (Wang et al, 2018) and the amount of P stored in vegetation (Wang et al, 2018;Zhang et al, 2021).…”

Toward a Global Model for Soil Inorganic Phosphorus Dynamics: Dependence of Exchange Kinetics and Soil Bioavailability on Soil Physicochemical Properties

“…Recently, He et al. (2021) published a global data set of soil phosphorus, which significantly improved the previous estimates of total soil P by Yang et al. (2013).…”