Multivariate diagnosis of the nutritional status of agronomic crops comprising (i) removal of dry matter from aerial parts and determination of histological contents, [e], in macro - and / or micronutrients, (ii) calculation of nutritional indices A / B, for each element for comparison with normal indices a / b, (iii) the comparison of these indices with indices of sufficiency, and (iv) the recommendation of [e] minimal. The establishment of the A / B standards with the A / B indices combines the adjustment of [e] for nutrients A, B ... Z, by extrapolation of an azo-nutrient function (FAN) [e] = f (NNI) if NNI = 1.00, and reciprocal and cross rational a / b comparisons of each nutrient. FAN describes the variation of [e] with respect to NNI according to an equation that is either polynomial, advantageously of degree 2, exponential, power, logarithmic, or even more logistically realistic and nonlinear including asymptotes. Rational nutritional indices are calculated according to DRIS or CND. Absolute nutritional indices are NNI (Nitrogen Nutrition Index), PNI or even KNI. Comparison of adjusted and unadjusted indices by division； if greater than 1.00, histological contents, although balanced, do not ensure a full yield. The basic recommendations are the difference ([e] x MSPA) adjusted and ([e] x MSPA) unadjusted.Diagnostique multivariée de l'état nutritionnelle de cultures agronomiques comportant le, (i) prélèvement des matières sèches des parties aériennes et détermination des teneurs histologiques, [e], en macro- et/ou en oligo - éléments, (ii) calcul d'indices nutritionnels A/B, pour chaque élément pour comparaison par rapport à des indices normaux a/b, (iii) la comparaison de ces indices à des indices de suffisances, et (iv) la préconisation de [e] minimales. L'établissement des normes a/b de avec les indices A/B combine l'ajustement des [e] pour les éléments nutritifs A, B ... Z, par extrapolation d'une fonction azoto - nutritonnelle (FAN) [e] = f(NNI) si NNI =
