EFFECT OF BIOFERTILIZERS, VERMICOMPOST, AZOTOBACTER AND BIOPHOSPHATE ON THE GROWTH, NUTRIENT UPTAKE AND ESSENTIAL OIL CONTENT OF DRAGONHEAD (DRACOCEPHALUM MOLDAVICA L.)

Biofertilizer application in medicinal plant production is important in sustain-able agriculture. The aim of this application is to remove or reduce the chemical input and to increase the quality and sustain the yield. The main aim of this study was to determine the effect of biofertilizers on the growth factors, nutrient uptake, and essential oil content in Dragonhead (Dracocephalum moldavica). This research was undertaken during two growing seasons in 2009 and 2010 at Tarbiat Modares University, Tehran, Iran. Experimental factors were vermicompost (V) at three levels (0, 15 and 30% pot volume), Azotobacter at two levels (treated and untreated) and biophosphate at two levels (treated and untreated). The results showed that the highest concentration of nitrogen (2.27%), phosphorus (0.22%) and potassium (2.51%), and the greatest shoot fresh weight (44.26 g), shoot dry weight (11.52 g), plant height (49.25 cm), seed weight per plant (4.02 g) and essential oil content (0.74%) were obtained by applying vermicompost at 30% of the pot volume. Biophosphate also had a significant effect on phosphorus concentration in the shoot of Dragonhead, and the highest concentrations of phosphorus (0.22%) were obtained with the application of biophosphate. There were positive and synergistic interactions between factors, for example between vermicompost and biophosphate on P concentration.