ISHS Acta Horticulturae 747: VIII International Symposium on Protected Cultivation in Mild Winter Climates: Advances in Soil and Soilless Cultivation under Protected Environment
AUTOMATION OF IRRIGATION IN HYDROPONICS BY FDR SENSORS - EXPERIMENTAL RESULTS FROM FIELD TRIALS |
| Authors: | E. Farina, F. Di Battista, M. Palagi |
| Keywords: | rose, cultivation, nutrition, water saving, Frequency Domain Reflectometry |
| Abstract:
At C.R.A. - Experimental Institute of Floriculture, Sanremo (Italy), a research aimed to develop a fertigation automation prototype system based on FDR technology has been carried out. The prototype has been evaluated for one year in a soilless cultivation of roses. The test was carried out on plants grown in coir dust in two equivalent groups of raised benches after a preliminary laboratory phase of probe calibration in this particular substrate. The first group of benches was equipped with a Theta Probe ML2x (Delta-T Devices Ltd) buried in the substrate and connected to an original controller for automation of fertigation. The probe output (mV) was constantly compared to a chosen setup value corresponding to a volumetric 30% water content (probe calibration) and fertigation started when such value was reached. A timer regulating the duration of fertigation allowed the pursuit of a 25–35% leaching fraction (L.F.) to maintain correct levels of electrical conductivity (EC) in the substrate. In the second group of benches fertigation was determined by a simple timer for time and duration of irrigation (weekly scheduling) fixing the same target of L.F. as before. Both groups of benches were provided with suitable equipment for calculating water balance (amount of supplied nutrient solution and of drain). Flower yield and quality were evaluated for both groups of benches. A substantial nutrient solution saving (59%) and a strong reduction of drained solution volume (52%) with a small decrease of total flower yield and quality were calculated in the case of the FDR probe based automation of fertigation in comparison with the traditional system based on the timer. The technology used proved itself reliable. No intervention for maintenance was necessary throughout the period of the trial. In conclusion, a handy facility is made available to the grower for a correct nutrient management in soilless culture. | |
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