The interaction between irrigation interval with manure and vermicompost on vegetative characteristics and yield of Lemon Verbena (Lippia citriodora L.)

This experiment was carried out to study the interaction between irrigation intervals with manures and vermicompost on vegetative characteristics and yield of Lemon Verbena a factorial experiment based on completely randomized design in Fasa, Iran during 2017. The first factor involved irrigation intervals at four levels including two, four, six and eight days. The second factor was the utilization of vermicompost and/or livestock manure in four levels consisted of a control test, five percent manure (by weight), five percent vermicompost and 2.5% manure + 2.5% vermicompost which were added to the studied soil in pots. Water stress caused a significant decrease in the leaf relative water content and chlorophyll index of lemon verbena. The lowest ion leakage was obtained in vermicompost and manure and the highest amount of malondialdehyde in control test. In general, the results of this study showed that with increasing in drought stress a negative effect was observed on growth of Lemon Verbena which finally led to the reduction of biological yield. Also, the utilization of vermicompost and/or manure fertilizer have a  positive effect on plant growth and improved plant's growth characteristics.