Phosphorus in agricultural soils: drivers of its distribution at the global scale

Bruno Ringeval (1) , Laurent Augusto (1) , Herve Monod (2) , Dirk van Apeldoorn , Lex Bouwman (3) , Xiaojuan Yang (4) , David Achat (1) , Louise Chini (5) , Kristof van Oost , Bertrand Guenet (6, 7) , Rong Wang (8) , Bertrand Decharme (9) , Thomas Nesme (1) , Sylvain S. Pellerin (1)

1 UMR ISPA - Interactions Sol Plante Atmosphère
2 MaIAGE - Mathématiques et Informatique Appliquées du Génome à l'Environnement [Jouy-En-Josas]
3 Universiteit Utrecht / Utrecht University [Utrecht]
4 ORNL - Oak Ridge National Laboratory [Oak Ridge]
5 Department of Geographical Sciences
6 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
7 MOSAIC - Modélisation des Surfaces et Interfaces Continentales
8 Peking Univ, Coll Urban & Environm Sci, Lab Earth Surface Proc, Beijing 100871, Peoples R China
9 CNRM - Centre national de recherches météorologiques

Phosphorus (P) availability in soils limits crop yields in many regions of the World, while excess of soil P triggers aquatic eutrophication in other regions. Numerous processes drive the global spatial distribution of P in agricultural soils, but their relative roles remain unclear. Here, we combined several global data sets describing these drivers with a soil P dynamics model to simulate the distribution of P in agricultural soils and to assess the contributions of the different drivers at the global scale. We analysed both the labile inorganic P (P ILAB), a proxy of the pool involved in plant nutrition and the total soil P (P TOT). We found that the soil biogeochemical background corresponding to P inherited from natural soils at the conversion to agriculture (BIOG) and farming practices (FARM) were the main drivers of the spatial variability in cropland soil P content but that their contribution varied between P TOT vs. P ILAB. When the spatial variability was computed between grid cells at half-degree resolution, we found that almost all of the P TOT spatial variability could be explained by BIOG, while BIOG and FARM explained 38% and 63% of P ILAB spatial variability, respectively. Our work also showed that the driver contribution was sensitive to the spatial scale characterizing the variability (grid cell vs. continent) and to the region of interest (global vs. tropics for instance). In particular, the heterogeneity of farming practices between continents was large enough to make FARM contribute to the variability in P TOT at that scale. We thus demonstrated how the different drivers were combined to explain the global distribution of agricultural soil P. Our study is also a promising approach to investigate the potential effect of P as a limiting factor for agroecosystems at the global scale.

Mots clés: biogeochemical cycles; phosphorus; modelling; global scale; agricultural soils

Domaines: Sciences de l'environnement

Bruno Ringeval, Laurent Augusto, Herve Monod, Dirk van Apeldoorn, Lex Bouwman, et al.. Phosphorus in agricultural soils: drivers of its distribution at the global scale. Global Change Biology, 2017, 23 (8), pp.3418 - 3432. ⟨10.1111/gcb.13618⟩. ⟨hal-01708836⟩