Determination of Agronomic and Essential Oil Properties of Peppermint (Mentha piperita L.) in Various Ages of Plantation

Abstract

Peppermint (Mentha piperita L.) is one of the high demand aromatic medicinal plants and essential oil extracted from the crop is extensively used in the fragrance, flavor and pharmaceutical industries. A field experiment was carried out during the periods of 1998-2001 in the Central Black Sea region climatic condition to investigate variation of yields, essential oil content and components during the years and harvesting periods in two local cultivated peppermint (M. piperita) varieties (from Gaziantep and from Adana) from Turkey and to determine economical yield levels. Since one harvest was made in both varieties in the 1st year, yield was low. Each variety was harvested two times in the 2nd and 3rd years and maximum total yields were obtained in the 2nd year in both varieties. While variety 1 was harvested one time in the 4th year, variety 2 did not grow well enough for harvest. Essential oil content of both varieties was higher in the 2nd harvest in 1999 and 2000. While higher menthol contents (56.7 and 56.4%) of the variety 1 were obtained from the 2nd harvests of 1999 and 2000, menthol contents were lower in the variety 2 in the 2nd harvest due to delayed harvests. Good quality of essential oil in the variety 1 was only obtained from 2nd harvests of 2nd and 3rd years, 1999 and 2000. But essential oil of variety 2 was good quality all years, except those of 2nd harvest of 2nd and 3rd years. While economic yields levels of variety 1 were obtained in 2nd (fresh herbage 25.96 t ha-1) and 3rd years (fresh herbage 20.40 t ha-1), economic yield level of variety 2 was obtained only in 2nd year with 26.25 t ha-1 fresh herbage yield and was lower than other years.