Organic and Chemical Fertilizer Affected Yield and Essential Oil of Two Mint Species

Abstract

Two species of mint Mentha piperitha (peppermint) and M. arvensis (Japanese mint) are widely cultivated in Iran but have not been evaluated their response to fertilizer regimes. A field experiment were conducted to investigate the effects of different organic and chemical fertilizer treatments [Control, 100 % urea (95 kg N ha”1), 75% urea (71.25 kg N ha”1) + 25 % Vermicompost (3.3 ton ha-1), 50 % urea (47.5 kg N ha”1) + 50 % Vermicompost (6.75 ton ha-1), 25 % urea (23.75 kg N ha”1) + 75 % vermicompost (10.1 ton ha-1) and 100 % vermicompost (13.5 ton ha-1)] on essential oil contents, yield and morphological parameters of two species of mint (peppermint and Japanese mint) at Tarbiat Modares University during 2015 growing season. Peppermint provided higher plant height, number of internodes, number of leaves and oil percentage than Japanese mint. The results indicated that, irrespective of mint species, plant treated with chemical and organic fertilizers together presented taller plant, higher oil contents and oil yield compared with solo chemical or organic fertilizers. Oil percentage and essential oil yield of mint increased significantly up to 25.75 kg/ha urea + 10.1 t/ha. Plant height and number of leaf increased along the replacement of organic fertilizer with chemical fertilizers. The results showed that there was positive and significant correlation with leaf number and essential oil yield. Application of vermicompost combined with chemical fertilizer increased plant height, oil percentage and essential oil in both species suggesting that organic and chemical fertilizer combination improves performance and environmental sustainability.