The efficiency of nutritional practices is evaluated by quantifying the concentration of nutrients in the soil solution and in the plant, a process known as nutritional monitoring. Since the plant absorbs nutrients exclusively from the liquid fraction of the soil, suction probes are installed at various depths to simulate root absorption and collect soil solution samples. This allows for understanding how much of the applied fertilizer and how much of the native nutrient supplement is available for the absorption by the crop. Nutrient metabolism efficiency (absorption + assimilation) is verified through the use of standard or specific foliar analyses. Accurate interpretation of the results helps estimate the soil’s capacity to supply nutrients to the plant and provides a diagnosis of the crop’s nutritional status.