Effect of Vermicompost and Planting Pattern on Oil Production in Satureja sahendica L. under Competition with Pigweed (Amaranthus retroflexus L.)

Abstract

The sahendi savory (Satureja sahendica Bornm.) is a native medicinal species of Iran which is subjected to extinction. Regarding to the importance of weed management and soil organic fertilization our study focused on plant growth responses to different nutrition systems and competition of redroot pigweed (Amaranthus retroflexux L.) in two planting pattern (rectangles, zigzag). Experiment was carried out in a randomized complete block design with three replications and factorial arrangement of treatments at the Ismael Abad Research Station, Qazvin Agriculture and Natural Resources Research Center on 2010 to 2012. Nutritional treatments include: NPK plus foliar application of micronutrients, four tone/ ha of vermicompost, two tone/ha vermicompost plus 40 liters/ha vermi-tea (liquid formulation of vermicompost). Pigweed density has also been studied at four levels of 0, 6, 12 and 18 plants per square meter. Effect of fertilizer treatments on essential oil percentage of sahendi savory was not significant and relative superiority of essence belonged to vermicompost fertilizer as 2 tone/ha plus 40 liters of vermi-tea .Also among the harvests second harvest was superior than first harvest. Weed treatment had no significant effect on essential oil percentage of sahendi savory. Thymol content in plots fertilized by 4 tons per hectare vermicompost was the highest value (42.95%) and had inverse relation with the p-cymen content (35.3%). Weed free condition produced the highest thymol content (45.18 %), meanwhile and the lowest amount (38.6%) were found in high weed density (18 plants per square meter).