effect of different substrates on tomato production in soilless culture

abstract this study was performed in order to determine a suitable alternative substrate for peat in soilless culture in 2007. different plant wastes including carbonized rice hull, saw dust and dry pine leaves (pinus eldarica) were examined. treatments were 100% peat as control, peat plus dry pine leaves (1:1 v/v), peat plus carbonized rice hull (1:1 v/v) and peat plus saw dust (1:1 v/v). the study was conducted in the pot and tube culture system in the research greenhouse of the college of agriculture, guilan university. the results showed that the peat plus carbonized rice hull was the best one as follows: the average total yield of was 8.7 kg m-2; the marketable yield was 7.3 kg m-2; and the most fruit set was 6.1 per plant and 70.6 of fruit per m-2. the highest total soluble solids (tss) content was 4.2o brix; also, potassium content 400, phosphorous 21.6, calcium 13.3 and magnesium 16.6 mg kg-1 were obtained from this substrate. fruits and the number of leaves and magnesium content were higher at 1% and the other differences were obtained at 5%. peat with the average of 38.6 cm had the most distance of the first inflorescence from substrate surface level, which was significantly higher than peat plus saw dust at level of 5%. there was no significant difference among the other characteristics. according to these results, mixed carbonized rice hull and peat (1:1 v/v) can be used as peat substitution in soilless culture substrates for tomato production. key word: tomato, peat, plant waste, soilless culture