Effect of cobalt supplement on rosemary (rosmarinus officinals L) A- herb yield, essential oil content and its composition

Abstract

Two field experiments were conducted in Research and Production Station, National Research Centre, Nobaria Location, Beheara Governorate, Delta Egypt.  Experiments were carried out to study the effect of cobalt concentrations (0.0, 5.0, 7.5, 10.0, 12.5 and 15.0 ppm) on Rosemary herb yield, essential oil content and its composition under drip irrigation system during 2012 and 2013 seasons. The obtained results indicate that:- All cobalt concentrations significantly increased all Rosemary growth and herb yield parameters compared with untreated plants. Cobalt at 10 ppm gave the maximum values of fresh herb and its biomass, essential oil and its composition. Increasing cobalt levels above 10 ppm in plant growing media cobalt promotive effect reduced.