effects of chemical and biofertilizers on yield and production factors of valerian (valeriana officinalis l.)

A field experiment was conducted to evaluate the effects of bio and chemical fertilizers on yield and production factors of valerian (valeriana officinalis l.) at the homad-absard agricultural complex in damavand city, tehran province, iran, through a factorial experiment based on a randomized complete blocks design with 3 replications during 2017 to 2020. experimental factors consist nitroxin and phosphate barvar2 biofertilizers each with 2 levels of inoculation and control, and also the urea (46% n) chemical fertilizer in 5 levels (0, 30, 60, 90 and 150 kg/ha). measured parameters were root diameter (mm), root length (cm), leaf width (cm) and leaf length (cm) root dry weight (kg/ha), shoot dry weight (kg/ha), valernic acid content (%) and valernic acid yield (g/ha). results showed that the biofertilizers had significant effect (p≤ 0.01) on the all quantity and quality parameters studied. unlike the urea chemical fertilizer at all levels which had a negative effect on the yield and amount of valernic acid (%), biofertilizers increased it. maximum and minimum amount of valernic acid (%) were measured in control (0.465%) and 150 kg/ha urea (0.215%) respectively. the highest and lowest root dry weight were obtained in interaction of nitroxin+phosphate barvar2 + 150 kg urea (665 kg/ha) and control (221 kg/ha) respectively. results of this experiment showed that biofertilizers with positive effects on experimental parameters are able to replace the chemical fertilizers.