Articles
EVALUATION OF A CONTROL SYSTEM BASED ON THE IRRIGAS® SENSOR FOR IRRIGATION SCHEDULING OF HYDROPONIC TOMATO IN CEARÁ, BRAZIL
Article number
889_54
Pages
431 – 438
Language
English
Abstract
The study aimed to evaluate two irrigation scheduling techniques for hydroponic tomato production in Ceará, northeastern Brazil.
The experiment was set up as a split-plot randomized block design, with six replications.
As main factor, two irrigation scheduling techniques were tested: (a) Automatic scheduling using matric sensors, a closed loop irrigation control system based on the Irrigas® sensor, was used to start irrigation whenever matric potential in the substrate reached -4 kPa. (b) Time clock scheduling – irrigation applications were programmed at fixed intervals and rates, according to drainage fraction observed on the previous day and water retention capacity of the substrate.
Tomato hybrids Miramar and Ellen were evaluated in the subplots.
The growing medium was coconut fiber in bags of 40 L. The automatic irrigation scheduling based on Irrigas® sensors did not affect significantly the tomato marketable yield, fruit weight, and number of fruits per plant (p>0.05) as compared to time clock scheduling. The automatic irrigation control reduced water application by 6.3% as compared to time clock scheduling, without affecting pH and EC levels of the drainage solution.
The tomato hybrid Miramar presented significantly higher (p<0.01) marketable yield and number of fruits per plant than hybrid Ellen, which presented higher fruit weight.
The experiment was set up as a split-plot randomized block design, with six replications.
As main factor, two irrigation scheduling techniques were tested: (a) Automatic scheduling using matric sensors, a closed loop irrigation control system based on the Irrigas® sensor, was used to start irrigation whenever matric potential in the substrate reached -4 kPa. (b) Time clock scheduling – irrigation applications were programmed at fixed intervals and rates, according to drainage fraction observed on the previous day and water retention capacity of the substrate.
Tomato hybrids Miramar and Ellen were evaluated in the subplots.
The growing medium was coconut fiber in bags of 40 L. The automatic irrigation scheduling based on Irrigas® sensors did not affect significantly the tomato marketable yield, fruit weight, and number of fruits per plant (p>0.05) as compared to time clock scheduling. The automatic irrigation control reduced water application by 6.3% as compared to time clock scheduling, without affecting pH and EC levels of the drainage solution.
The tomato hybrid Miramar presented significantly higher (p<0.01) marketable yield and number of fruits per plant than hybrid Ellen, which presented higher fruit weight.
Authors
F.R. Miranda, A.L.M. Mesquita, M.V.V. Martins, F.A.S. Aragão, C.M.F. Fernandes
Keywords
Lycopersicon esculentum, soilless culture, matric potential, irrigation control, greenhouse
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