The effects of Bio fertilizers and chemical phosphorus fertilizers on quantity and quality yield of John,s wort (Hypericum perforatum L.)

In order to study the effects of biofertilizers on the quantity and quality of John’s wort (Hypericum perforatum L.)، an experiment was conducted at Shahed University in 2010. The studied factors included phosphatic biofertilizer (inoculated and non-inoculated)، phosphorous fertilizer at three levels (0، 100، 200 kg/h) and vermicompost (0، 5، 10 ton/h). The study was conducted in a factorial experiment in the form of a randomized complete blocks design (RCBD) with three replications. In addition، one plot was considered as control group in each replication to be compared with other plots in which only chemical fertilizers (NPK: 250، 200 and 100 kg/h) were used. Results showed that the highest biological yield، flowering shoot yield، and hypericin yield were obtained by applying vermicompost at 5 ton/ha، and there was no significant difference between the application rates of 5 and 10 ton/ha. The interaction effects of phosphatic biofertilizer (inoculated) and phosphorous fertilizer were significant، so that the highest biological yield، flowering shoot yield، hypericin yield and chlorophyll a were obtained by applying 100 kg/ha P2O5 plus phosphatic biofertilizer، having no significant difference with the application rate of 200 kg/ha P2O5. Significant differences were found between biofertilizer treatments and control group. According to the obtained results، it seems that biofertilizers can be considered as a replacement for chemical fertilizers.