Automated management of nutrient solutions based on target electrical conductivity, ph, and nutrient concentration ratios

Abstract An algorithm to automatically formulate the composition and prepare nutrient solutions for soilless cultures based on desired characteristics given as target values is proposed. To formulate the complete ionic composition of a nutrient solution, standard recommendations referring to the following solution characteristics should be available: (i) electrical conductivity (EC), (ii) pH, (iii) concentration ratios of macronutrients (meq basis), and (iv) micronutrient concentrations. Moreover, the mineral composition of the water used to prepare the nutrient solution should be taken into account. To develop the main steps of the algorithm, the total salt concentration (meq L‐1) of the nutrient solution is related to the desired electrical conductivity. The target pH indicates the concentration of HCO3 − in the nutrient solution, whereas the absolute concentration of each macronutrient is derived from the desired concentration ratios and the total salt concentration. The necessary calculations are stan...