Effect of soil type on growth, productivity, and essential oil constituents of rosemary, Rosmarinus officinalis

Rosemary, Rosmarinus officinalis L., is a remarkable medicinal plant containing number of phytochemicals with pharmaceutical and flavoring uses. As part of development of agro technology package of practices for large scale cultivation of rosemary, experiments were designed to examine the influence of soil texture using different ratios of sand and loam soil.Pot experiments were conducted at the Experimental Station of National Research Centre during 2015 and 2016 successive seasons. To determine the best soil texture and type for rosemary cultivation, seven different combinations of sand: loam (100:0, 75:25, 66.75: 33.25, 50:50, 33.25:66.75, 25:75, and 0:100) were filled in 30cm pots where shoot tip cuttings of rosemary were planted.All growth characters such as plant height, number of branches, herb fresh and herb dry weight were measured. Maximum values were recorded in 100% loam soil comparing with other soil types. Essential oil yield was also higher in 100% loam soil compared to others. Results showed that soil types had a pronounced effect on chemical constitutions of essential oil with higher major constitutions, camphor and α-pinene, under sand soil. These results suggest cultivation of rosemary in loamy soil for higher productivity as well as in sandy soil for higher quality.