The aim of this study was to evaluate the effect of hydrogen peroxide (H2O2) as an oxygen source in the rhizosphere, in grafted tomato (cv. Durinta/cv Maxifor) and using coconut fiber as substrate The study was conducted from 2009 to 2010. Two treatments were used: a control without (H2O2) (T0) and the other with H2O2 (T1) applied in each irrigation. The parameters evaluated were i- fertigation: oxygen concentration ([O2]), pH, electrical conductivity (EC), and drainage percentage; ii- growth: basal diameter and plant height; iii- yield and iv- fruit quality: firmness, Brix degrees, dry weight, and pH. The average value of [O2] in the irrigation solution through out the crop cycle increased from 9,92 mg/l at T0 to 12,1 mg/l at T1 (P<0,05), meanwhile in the drained solution the value increased from 8,75 mg/l at T0 to 9,22 mg/l at T1 (P<0,05). Although significant differences (P<0.05) were reached in the [O2] between treatments during some periods of the crop cycle, the [O2] in the T0 did not reach a critical threshold that would affect the proper oxygenation of the roots. Therefore, there was no effect of hydrogen peroxide treatment on the growth, productivity and quality of the fruit.

Keywords: green chemistry, rhizosphere, hypoxia.