Abstract
Yield of fresh and dry Echinacea purpurea (L.) Moench roots was evaluated in relation to spacing in solarized soil in a semi-arid Mediterranean region, and the change in microbial contamination of pressed fresh root juice, preserved in honey and ethanol, was compared for a period of 1 year. Three within row spacings were tested; 40, 50 and 60 cm. The soil was solarized for 40 days before E. purpurea seedlings were transplanted in the field. Solarization was accomplished by covering moistened soils of all plots with transparent clear 50 μ thick polyethylene sheets, leading to elevated temperatures above 40°C. Fresh and dry root yield per unit area from plants spaced at 40 and 50 cm was similar and significantly higher than that from plants spaced at 60 cm. Fresh and dry root yield per plant was highest for the 50 cm within row spacing, significantly different from yields of plants spaced 60 cm apart. Aerobic bacterial count, spore-former anaerobic bacterial count and mould count did not differ between honey and ethanol-preserved root juice over a one-year period. In conclusion, within row spacing of 50 cm, in conjunction with soil solarization, was most efficient for root production of Echinacea purpurea (L.) Moench. Also, root juice preservation in organic honey produced similar results in terms of prevention of microorganism proliferation, over a one-year period, as that obtained by the traditional use of ethanol as a preservative.