Chemical processes and prediction of dissolved phosphorus leaching in mineral and organic soils

•Subsurface phosphorus (P) loss should be reduced in livestock-intensive areas.•Chemistry of both topsoils and subsoils are important for dissolved P leaching.•Whole-profile degree of P saturation predicts total dissolved P concentrations.•Groundwater- and rain-fed organic soils behave differently in affecting P leaching.•Dissolved organic P needs studies on its origin, transport and bioavailability. In agricultural areas dominated by subsurface drainage, leaching of phosphorus (P) from soils is a concern for downstream water quality. Still, the role of chemical processes in subsoils and organic soils in influencing dissolved P leaching needs to be clarified for better predicting the P leaching. In ten mineral and organic soils, we examined a wide range of chemical characteristics including various P pools and sorption–desorption properties at different soil depths and related those characteristics to leaching of dissolved P at the drain depth in an indoor lysimeter experiment. Results showed significant correlations between different P pools (R2-adj = 0.61 to 0.98, p