Long-term effect of super phosphate fertilizer on accumulation of soil phosphorus on a pasture

The purpose of the present work was to clarify some aspects of the complexity of phosphorus (P) dynamics under specific soil and climate conditions and a particular type of agro ecosystem: the Mediterranean pasture. The deviation between measured and estimated soil P content was evaluated over 12 years, in a 6 ha permanent bio-diverse pasture field in Southern Portugal. A simple dynamic model found good agreement for estimating the soil P content where P fertilizer had been regularly applied, but was not nearly as effective for the period during which the field did not receive P fertilizer. The dynamic of transformation between diverse P pools in Mediterranean shallow soils make the estimation of P balance very complex and justify more experiments.