02084naa a2200229 a 450000100080000000500110000800800410001910000220006024501310008226000090021352013810022265000210160365000280162465300150165265300230166765300210169070000230171170000220173470000240175670000240178077300500180419009862018-10-16       2011    bl uuuu     u00u1 u    #d1 aMIRANDA, F. R. de  aEvaluation of a control system based on the Irrigas® Sensor for irrigation scheduling of hydroponic tomato in Ceará, Brazil.  c2011  aThe 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&gt0.05) 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&lt0.01) marketable yield and number of fruits per plant than hybrid ?Ellen?, which presented higher fruit weight.  asoilless culture  aLycopersicon Esculentum  aGreenhouse  aIrrigation control  aMatric potential1 aMESQUITA, A. L. M.1 aMARTINS, M. V. V.1 aARAGAO, F. A. S. de1 aFERNANDES, C. M. F.  tActa Horticulturaegv. 889, p. 431-438, 2011.