Abstract

Age of plantation and season of harvest of Eucalyptus citriodora are important to derive essential oil with proper chemical composition. The studies were conducted to understand the influence of these factors on foliage yield and oil content and composition and also soil properties in some commercial plantations of E. citriodora in a semi-arid region of Karnataka, India. Leaf yield of E. citriodora was significantly higher in >10 years old plantations compared to 5–10 and <5 years plantations. Rainy season (August month) harvest recorded significantly higher leaf yield than summer and winter season harvests. Essential oil content of leaves ranged between 2.1 to 2.6% in different aged plantations and 2.4 to 2.5% during different seasons. Oil content was significantly higher in plantations > 5 years old and rainy season harvested leaf (2.54%). Oil content was low when temperature was high during November to March (2.47%). At this condition, the major chemical constituents of oil were citronellal (79.7 to 83.2%) and citronellol (5.5 to 6.7%). Concentration of citronellal decreased during rainy seasons (80.04%) as compared to winter (81.75%) and summer (81.16%). Age of plantation had significant effect on soil quality parameters; as the age of plantation increased available P, K, OC, Ca, Mg, Cu, Mn, Fe and B content decreased, whereas available N, S and Zn contents increased. Soil pH of E. citriodora plantations (5.86–6.60) increased over open area (5.07). To harvest high yields with good quality foliage of E. citriodora, soil fertility management needs attention to replenish some plant nutrients.