Prediction of long-term crop response to fertilizer P should result In more efficient use of this resource. To achieve this, a simple model designed to calculate the long-term recovery of fertilizer P was de veloped and is presented here. In the model, both a labile and a stable P pool are distinguished. With time intervals of l yr, the model calculates the P transfers between the pools, the uptake of P by the crop, and the resulting pool sizes. Most input data required to operate the model can be obtained from ordinary one-season fertilizer P trials. Input data, model parameters, and initial pools can be derived from field trials, and the model can be used to calculate long-term recovery of fertilizer P. The sensitivity of the model is demonstrated by changing par~meter values. The model can also be used to es tablish long-term fertilizer recommendations for a certain target P uptake. Required rates of fertilizer P are calculated for different soils, fertilizer types, target uptakes, and periods of time. Additio1Ull indu words: Fertilizer recommendations, Labile phos phorus, Phosphorus uptake, Simulation model, Soil phosphorus cy