The present disclosure relates to an agricultural monitoring system and method for monitoring a nutrient flow within an agricultural site. The method comprises the steps of detecting a quantity related to a carried material of a known material type; determining a nutrient content of the captured material based on the detected quantity and based on at least one nutrient content parameter value associated with the carried material; obtaining information related to a source location and a target location for the carried material, and forming information related to the nutrient flow, said information comprising the source location, the target location, information related to the determined nutrient content of the carried material and preferably material type of the carried material.