Assessing the Role of Phosphorus as a Macropollutant in Four Typical Mediterranean Basin Soils

Abstract

Available phosphorus (AP) is a key macropollutant predictor of ecosystem services as well as a crucial indicator of soil productivity. Long-term applications of this macronutrient and its implications on sustainability in the face of peak phosphorus harvest have raised some concerns in recent years. This study aimed to characterise the edaphic AP in nearly 15,000 ha of the Mediterranean basin, an agricultural study area whose intensification is increasing with time. Four typical Mediterranean reference soil groups (RSG)—Calcisols, Luvisols, Fluvisols and Cambisols—were analysed and compared for their AP in two different agricultural settings—rain-fed and irrigation—from 2002 to 2012, where 1417 and 1451 topsoil samples were taken, respectively. AP increased from 2002 to 2012 in the irrigated Luvisols (p < = 0.05), Fluvisols (p < = 0.01) and Cambisols (p < = 0.05), while irrigated Calcisols maintained its concentrations (p > 0.05) over time. For rain-fed soils, the AP did not reveal significant differences in time for all RSG (p > 0.05). Additionally, irrigated Fluvisols and Cambisols presented 9% (p < = 0.01) and 68% (p < = 0.01) higher AP concentrations, respectively, than the corresponding rain-fed RSGs in 2012. We provide predictive maps for both 2002 and 2012. These results suggest that this area is departing from the sustainable goals of ecosystem services equilibrium; proper management practices that counteract the anthropogenic pressures in the area should be adopted.