The effect of the application method and different concentrations of humic acid on the performance and absorption of mineral elements of miniature roses of Haft Rang variety

This study was conducted to investigate the effects of soil application and spray solution of humic acid on growth characteristics, flowering, and nutrient absorption of miniature rose cultivar Haft Rang in a completely randomized design with two humic acid factors at 4 concentrations (zero, 500, 1000, and 2000 mg/L) and two application methods (soil application and spray solution) with three replications and two observations in the research greenhouse of Urmia University in 2013-2014. The results of the experiment indicated a significant effect of humic acid on vegetative traits (such as fresh and dry leaf weight and stem diameter), reproductive traits (such as number and diameter of buds, flower diameter), and nutrient absorption of Haft Rang miniature rose. The results showed that soil treatment of 2000 mg/L humic acid caused the highest nitrogen (8.425 micrograms per pot) and iron (8.12476 micrograms per pot) uptake in the plant, but the zinc uptake was not significant at any of the humic acid concentrations. The highest copper absorption was also achieved in the treatment of spraying solution of 1000 mg/L of humic acid (342.46 micrograms per pot). In the absorption of manganese and potassium, the concentration of 1000 mg/L also caused the highest absorption of potassium and manganese. In general, it can be concluded that the application of humic acid to plants increases the absorption of some essential elements and plant growth.