A nutrient solution management technique based on the length of a leaf of a greenhouse tomato, comprising the following steps: 1, subtracting from the leaf length of a feature leaf of a greenhouse tomato a standard leaf length for the feature leaf, excess water and fertilizer supply being indicated if the result is greater than zero, insufficient water and fertilizer supply being indicated if the result is less than zero, and adequate water and fertilizer supply being indicated if the result is equal to zero； 2, subtracting from the current electric conductivity value of a nutrient solution used in watering the EC value of the nutrient solution in a water and fertilizer deficit condition, multiplying the difference by the number of days the nutrient solution has been used in watering, and the result being the amount of nutrients of the nutrient solution excessively or insufficiently applied, and utilizing the average growth rate, a, of the feature leaf to deduce the current electric conductivity value of the nutrient solution used in watering； and 3, determining, on the basis of the amount of nutrients of the nutrient solution excessively or insufficiently applied, a final electric conductivity value of the nutrient solution for adjustment, and watering the crop with the adjusted nutrient solution. Only the length of the feature leaf of the greenhouse tomato needs to be measured, one-time investment incurred is low, and the measurement is simple and easy.La présente invention concerne une technique de gestion de solution nutritive basée sur la longueur d'une feuille d'une tomate de serre comprenant les étapes suivantes : 1, soustraire de la longueur de feuille d'une feuille caractéristique d'une tomate de serre une longueur de feuille standard pour la feuille caractéristique, un apport excédentaire d'eau et d'engrais étant indiqué si le résultat est supérieur à zéro, un apport insuffisant en eau et en engrais étant indiqué si le résultat est inférieur à zéro, et un
