an investigation into the effect of humic acid application on some morphological and physiological characteristics of china rose

In recent years, excessive use of chemical fertilizers and lack of organic fertilizers caused to reduce the rate of soil organic matter in iran. the increased use of chemical fertilizers in agriculture causes environmental problems such as soil physical degradation and soil nutrient imbalances. this study was conducted to investigate the effects of foliar and soil applications of humic acid on some morphological and physiological characteristics of rosa chinensis ‘baby masquerade’ in the completely randomized design with two factors; four concentrations of humic acid (0, 500, 1,000 and 2000 mg/l) and two application methods (soil and foliar application) for 8 times (every 15 days) with three replications and two observations per replication under controlled greenhouse conditions. the results showed that humic acid had additive effects on anthocyanin and total soluble solids content. it should be noted that increasing of the content of total soluble solids cause to increase anthocyanin. foliar application of 500 mg/lhumic acid significantly increased chlorophyll content and photosynthetic rate. also, foliar application of 1000 mg/lhumic acid increased the total soluble solid content more than the other treatments. humic acid had significant effects on leaf area index and shoot and root fresh and dry weight. generally, it seems that humic acid can improve morphological and physiological characteristics of rosa chinensis var. ‘minima’.