Project Summary:

One of the challenges in cultivation in a hydroponic system with closed irrigation system is the optimized nutrient regulation due to inaccurate information of composition, although many researchers describe the determination of concentration of individual ions in solution as the key information for optimized operation. Current practice is the determination of conductivity, pH, redox potential and temperature. The consequence is the limited possibility to adjust nutrients to the needs of individual crops to avoid deficiency or eutrophication. The operators therefore periodically drain and replace the nutrient solutions.

The aim of the project is to develop an on-site multi-ion monitoring system for automated on-line control of nutrient input in vertical hydroculture systems with closed circulation systems based on feedback-controlled supply of nutrients. The monitoring system enables the effective use of nutrients for optimal plant growth by targeted regeneration of nutrient solution and thus contributes to a reduction in water pollution due to the premature nutrient disposal into the environment. Nutrient monitoring is based on direct potentiometric determination of relevant ions using ion-selective sensors. The choice of ions is characteristic of the growth of five crops selected. The sensors are integrated into a microfluidic system, which enables automated sample collection and adjustment of the measurement matrix. Calibration, data acquisition/processing are carried out using "machine learning" algorithms developed in the project to compensate for non-linear effects due to ion interference/cross-sensitivity and electrode/temperature drift. Prototypes will be provided to end users in India for beta testing.