Phytotoxicity and phenolic compounds content in soil during long-term cultivation of lemon balm (Melissa officinalis L.) and its effect on herb yield and essential oil content

BARBARA POLITYCKA, KATARZYNA SEIDLER-ŁOŻYKOWSKA

Abstract

The object of experiments carried out in 2007 and 2008 were plants of lemon balm (Melissa officinalis L.) which were at that time in the 1st, 3rd and 4th year (2007) and in the 2nd, 4th and 5th year (2008) of growing. The soil from plots on which the plants were grown was studied as well. The yield of fresh and dry matter of the herbal raw material as well as the essential oil content in the raw material were determined. Furthermore, the soil phytotoxicity and phenolic compounds content in the soil were studied. Maximum yield of the fresh and dry weight of the herbal raw material were obtained in the 3rd and 4th year of plant cultivation and it was maintained on an unchanged level in the 4th and 5th year of growing. As the time of lemon balm growing was elongated, the increase of essential oil yield was observed. Phytotoxicity of soil occurred seasonally – in spring and in autumn and did not depend on the year of growing duration. On the other hand, the content of phenolic compounds in the soil increased gradually with the long-term cultivation. However, the phenolic compounds did not accumulate in such amount as to exert a negative effect on the plants. Key words: lemon balm, long-term cultivation, soil phytotoxicity, phenolic compounds, herb yield, essential oil
Number of visits: 1993399