The Effects of Solitary and Combined Application of Cattle Manure and Chemical Fertilizer on Essential Oil and Some Physiological Characteristics of Moldavian Balm (Dracocephalum moldavica L.) under water Deficit Stress Conditions

Management of manure and chemical fertilizers application in the soil in terms of environmental impacts and performance of plants is important, especially in arid and semi-arid regions of Iran. A split plot experiment was carried out in a randomized complete block design with three replications at the research farm of Shahrekord University in 2014. Main factor was consisted of three levels of irrigation regimes including 100% (I1 or control), 75% (I2) and 50% (I3) of water requirement while 6 levels of manure application including 1) no amended fertilizer (control), 2) 25% urea fertilizer + 75% cattle manure 3) 50% urea fertilizer + 50% cattle manure 4) 75% urea fertilizer + 25% cattle manure 5) 100% urea fertilizer and 6) 100% cattle manure, were considered as subplot factor. Results showed that irrigation regime of I3 caused decreasing an contration of chlorophyll a, b and total, essential oil yield of flowering branch, leaf and stem while in caused 83 and 13.5 percent increase in the amount of carotenoids and proline compared to control, respectively. Fertilizer treatments, 25% urea fertilizer + 75% cattle manure, 50% urea fertilizer + 50% cattle manure, 75% urea fertilizer + 25% cattle manure, 100% urea fertilizer and 100% cattle manure caused significant increase in carotenoids content compared to control whereas the maximum carotenoids content with the average of 1.35 mg g-1 was obtained from the 25% urea fertilizer + 75% cattle manure treatment. A significant positive correlation was observed between chlorophyll a, b, total, essential oil percentage, essential oil yield of leaf and essential oil yield of flowering branches. Therefore, in order to obtain the maximum essential Moldavian balm under Shahrekord climatic condition, application of 50% urea + 50% cattle manure and full irrigation is recommended.