Design of Online Fertigation Machine and Study on Stability of EC Value

In the soilless cultivation system of facility agriculture, the stability of nutrient solution which as the main nutrient source of crops is particularly important, and the EC value（The value of Electrical Conductivity）is an important indicator to measure the ion concentration in nutrient solution. This article designs an online fertigation machine that meets the requirements of nutrient solution configuration and supply through pipeline system design and control system design, and conducts operational tests on it in a production environment. By continuously tracking the operating data of the fertigation machine in the production environment, analyzing the reasons for the unstable EC value, ultimately identify three factors that affect the stability of the EC value: PID algorithm, pipeline system design and the water pressure stability of water supply system.