Method of calibration of the diagnostic of the physiological state of agronomic cultures provide a variable by weight (vp) describing the abundance of the photosynthetic apparatus from a variable reactive (vr) describe its operation comprising • the sampling and / or the systematic or random sampling of the biomass of a culture agronomique to evaluate the vp and vr, either from plants are individual and / or areas harvested by way of samples of a surface of the ground grass, • conversion of the biomass in agronomic equivalent surface, such that g / m2, kg / ha or metric tons / ha, on the n samples, the measurement of a set of n observations commensurable on at least one vp and vr, the application of an incremental frame comprising a set of n of these n observations, or [vp] and [t] n, and the instep, the establishment of a measurement of the central value for the said n observations, the establishment of a measurement of the dispersion to these same n observations included in said frame incremental, characterized in that: • the set of n observations is previously the ordinate in gradually, sorted as a result, according to the vp to which is correlated the vr, during the determination of the central values and / or dispersions relating to these vp and vr from the sets of n observations included in the abovementioned frames incremental, those - these are moved, slipped as a result, after each determination by an increment regularly. • the aforesaid central values and dispersions relating are connected (correlation), or [vp] n: [t] n.Procédé de calibration de diagnostiques de létat physiologique de cultures agronomiques prédisant une variable pondérale (VP) décrivant labondance de lappareil photosynthétique à partir dune variable réactive (VR) décrivant son fonctionnement comprenant &bull léchantillonnage et/ou le prélèvement systématique ou aléatoire de la biomasse aérienne dune culture agronomique pour évaluer des VP et VR, soit à partir de plants individuels et/ou
