Comparison of the Effect of Organic and Chemical Fertilizers on Yield and Essence of Peppermint (Mentha piperita L.)

This study compared organic and chemical fertilizers on qualitative yield and essence content of peppermint. The experiment was carried out as Randomized Complete Design in Agricultural Farm Center, Sari, Iran, in 2013. The treatments were as control, vermicompost, composed sheep manure and basic chemical fertilizers at N60, P50, K60; N60, P80, K60; N90, P50, K80 and N90, P80, K80, and replicated four times. The results showed that all the measured characteristics were significantly (p<0.05) influenced by both organic and chemical fertilizers at the two harvest times. The values of the quantitative (wet and dry yield) and qualitative characteristics (essence content and essence yield) were also more at the first harvest than the second harvest. At the first harvest, the maximum value for dry and wet yield, and the maximum essence value and its yield were attained by using both sheep manure and chemical fertilizers at the rate of N90, P80, K80. The highest value for dry (96 kg ha-1) and wet (207 kg ha-1) yield, and yield (0.46 lit ha-1) and content of essence (0.48 g/100 g) were obtained with vermicompost. The values obtained for vermicompost and sheep manure were not significantly different. Application of sheep manure and vermicompost as organic fertilizer was recommended for production of peppermint. Whereas essence content and yield for first harvest were significantly higher than other treatments and control.