Amirhossein Najarian - Department of Horticultural Science ,Karaj Branch, Islamic Azad University ,Karaj, Iran
Mohammad Kazem Souri - Department of Horticultural Science ,Tarbiat Modares University ,Tehran, Iran

Compost produced from sugarcane bagasse was substituted at a range of different concentrations into soil bedding medium mixture, to evaluate their effects on the growth of Pelargonium × hortorum. Plants were grown in a substrate mixture (۲۵% leaf compost; ۲۵% cow manure; ۵۰% garden soil (volume) as control and substitution with different rates of sugarcane bagasse compost of ۲۰%, ۳۰%, ۴۰%, ۸۰% and ۱۰۰% were applied in three replications. The results showed that application of sugarcane compost started to stimulate plant growth at ۲۰% level and continued over other levels; however, there was no significant difference among sugarcane compost levels regarding many growth traits. Application of low rates particularly ۲۰% resulted in the highest record regarding many morphological traits including number of leaves, lateral stems, flowering shoots, flowers, inflorescence diameter, main shoot diameter, shoot and root biomass, and phosphorus concentration. Moreover, nitrogen and potassium concentrations were highest at ۴۰% treatment. A positive increase in chlorophyll a but not chlorophyll b was found by application of all levels of sugarcane compost compared to control plants

geranium, sugarcane bagasse compost, growth traits, essential elements