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).

The Qinghai–Tibet Plateau is a proven essential water conservation region in Asia. However, various factors, such as anthropogenic activities, climate, and vegetation significantly affect its water conservation. Along these lines, a deep understanding of the spatiotemporal patterns of water conservation for this plateau and relevant influencing elements is considered of great importance. This paper calculates the water conservation on the Qinghai–Tibet Plateau based on the InVEST model, and given that the evapotranspiration data are an important parameter of the InVEST model, this study selects the mainstream evapotranspiration data to compare the accuracy of the simulated water yield, and also selects the most accurate remote sensing evapotranspiration data examined in the study to carry out the study of water conservation on the Qinghai–Tibet Plateau. Due to the large area of the Qinghai–Tibet Plateau and the various types of climate and ecological zones, this paper analyzes the spatial and temporal variations of water conservation on the Qinghai–Tibet Plateau in each ecological zone and climate zone division and detects the factors affecting water conservation on the Qinghai–Tibet Plateau by using the geo-detector method. From our analysis, the following outcomes are proven: on the Qinghai–Tibet Plateau, (1) the overall water conservation decreased from southeast to northwest; (2) the water conservation of the studied plateau in 1990, 2000, 2010, and 2020 was 656.56, 590.85, 597.4, and 651.85 mm, respectively; (3) precipitation, evapotranspiration, and NDVI exhibited a positive relationship with water conservation; (4) the precipitation factor had the biggest impact on the spatial distinctions of the water resource governance; (5) the above factors are combined with the slope factor and the interaction of each factor to improve water conservation. Our work provides valuable insights for the further implementation of ecological projects with a view to enhancing water resource management methods.