Effect of Organic and Chemical Fertilizers on Yield and Yield Components of Peppermint (Mentha piperita L.)

The current study examined the effect of chemical and organic fertilizers on yield components and essence content of peppermint (Mentha piperita L.). The experiment was carried out in randomized complete design with 7 treatments and 4 replications in Sari Agricultural Research Center, Iran, in 2013. Treatments were: 1-control, 2-sheep manure, 3-vermicompost, and basic chemical fertilizers at different contents as 4-N60,P50,K60 kg ha-1 which equals 0.24, 0.2 and 0.24 g per pot, respectively), 5-N60,P80,K60, 6-N90,P50,K80 and 7-N90,P80,K80. There were 28 pots that 10 kg soil was added to each of those and chemical fertilizer (at determined rates), sheep manure and vermicompost fertilizers (both at the content of 20 ton ha-1 equal 80 g per pot) were also added in per selected pot as treatment. The results showed that the effect of all treatments was very significant on the all agronomic properties and yield of peppermint. Some agronomic and quantitative traits of peppermint like plant height, number of chain, stem wet and dry weight, leaves wet weight and total wet and dry weight were obtained at the maximum values when basic chemical fertilizers was applied at the rate of 90-80-80. The maximum number of stems, number of flowers, number of suckers, leaves dry weight and essence content were also attained by sheep manure. Thus, to prevent soil, plant and finally environment pollution by using chemical fertilizers and also to achieve the maximum leaves dry weight and essence content of peppermint, application of sheep manure as organic fertilizers is recommended.