Effect of Calcium on Growth Performance and Essential Oil of Vetiver Grass (Chrysopogon zizanioides) Grown on Lead Contaminated Soils

Abstract

The aim of this study was to investigate effect of calcium on growth, survival, essential oil yield, and chemical compositions of vetiver grass grown on lead contaminated soils. Calcium in form of CaCO₃ (0, 2000, 4000, 6000 mg Ca kg⁻¹) was added to river sand soils containing 4000 mg Pb kg⁻¹ dry soil. Results showed that, in the absence of calcium treatment, no plants survived after 2 weeks of cultivation, while the rest grew well to the end of the experimental period (42 weeks). Calcium treatments generally resulted in a slight decrease in biomass. Interestingly, an increase in calcium over 2000 mg kg⁻¹ did not result in a decrease in accumulation of lead in vetiver roots and shoots. The levels of lead in roots and shoots under calcium treatments were around 2000 and 90 mg kg⁻¹ dry weight, respectively. The addition of CaCO₃ did not improve vetiver essential oil yield and chemical composition compared to the control. A level of applied CaCO₃ about half of the lead concentration in soils was sufficient to improve vetiver growth and survival, and accumulate high concentrations of lead in the roots. This finding can be applied for re-vegetation of lead contaminated soils using vetiver.

KEY WORDS:

• CaCO3
• essential oil
• re-vegetation

ACKNOWLEDGMENT

The financial support from the Vietnamese Ministry of Education and Training and Gelita Australia Pty Ltd. are greatly appreciated. We would like to thank Van Bong Dang and Ngoc Thanh Vo for technical assistance.

The manuscript is part of the 6th International Phytotechnologies Conference.