SUMMARY
A field experiment was conducted to evaluate the effects of biocyclic humus soil, a newly found apparently carbon stabilized form of organic matter with significantly different characteristics from common composts or other forms of organic matter (humus), on yield and quality of processing tomato. The experiment was laid out in a completely randomized design with three replications and three fertilization treatments (untreated, inorganic fertilizer and biocyclic humus soil). The highest fruit yield (116.8 t/ha) was obtained by using biocyclic humus soil. There were no treatment effects on fruit firmness (4.34-4.60 kg/cm2), total soluble solids (4.29-4.76 °Brix) and total acidity (0.25-0.31 g citric acid/100 g fruit) content of fruits. In conclusion, the tomato plants grown in biocyclic humus soil had 45% more yield than in conventional plots, and this big difference is probably related to the fact that the humus soil as a substrate provides an optimum environment for plant growth.