Phosphorus management at field level must be simple and based on soil test as phosphorus bioavailability plays a prominent role in crop nutrition. It has also to take care of the availability of organic products or manure at farm level. The method proposed by COMIFER since 1993 to interpret soil test is based on a broad dialogue involving researchers as well as agricultural advisors. The method is based on laboratory research results and on a large set of field trials, conducted by all these actors. The interpretation procedure takes into account the crop sensitivity class. It is the major factor which leads the fertilization strategy. It uses two reference thresholds for every soil type and crop class combination. It also takes care of the availability of phosphorus due to fertilizers applications in previous years. The COMIFER method has had several evolution steps and is still nowadays the common basis for the various decision methods used in France. The method is updated by the COMIFER P-K-Mg group and is still evolving to and integrate new references (manure and slurry quality, new organic fertilizers,…) and adapt to new concepts. Present works deal with the use of more mechanistic phosphate dynamics principle to better integrate the role of soil buffer power in fertilizer rate calculation.