Fig. 10
Comparison between previous estimates (McDowell et al.58, Zhang et al., GPASOIL-v0) and our best estimates (GPASOIL-v1.1) for Pi-lab and Px-tot for cropland and grassland when available. Grassland were not simulated in Zhang et al.12 (and while Sattari et al.82, based on the same approach, focused on grassland, they did not provide nor discuss the distribution in grasslands). McDowell et al.58 provided Olsen P concentration for top 0–0.2 m at 1 km2 resolution for any land-use categories. We used the land-use information used in their study to filter their estimates and computed soil P for cropland and grassland only before changing the projection and regriding to half-degree resolution. Soil P concentration was converted in kgP ha−1 for top 0–0.3 m by using the bulk density used in our study and by assuming that the P concentration is representative to 0-0.3 m top soil layer. Note that Pi-lab of McDowell et al.58 is based on Olsen P extraction while pools design in other estimates plotted in this Figure is based on Hedley fractionation. McDowell et al.58 did not provide Px-tot.
