Industrial Crops and Products 45 (2013) 270–278 Contents lists available at SciVerse ScienceDirect Industrial Crops and Products journa l h o me pag e: www.elsevier.com/locate/indcrop Productivity, essential oil yield, and heavy metal accumulation in lemon grass (Cymbopogon flexuosus) under varied wastewater–groundwater irrigation regimes Khajanchi Lal a,∗ , R.K. Yadav a , Ravinder Kaur b , D.S. Bundela a , M. Inayat Khan a , Madhu Chaudhary a , R.L. Meena a , S.R. Dar a , Gurbachan Singh a,1 a Central Soil Salinity Research Institute, Karnal 132001, India b Water Technology Centre, IARI, New Delhi 110012, India a r t i c l e i n f o Article history: Received 7 August 2012 Received in revised form 20 December 2012 Accepted 1 January 2013 Keywords: Aromatic and medicinal plants Conjunctive use Optimum loading Metal contamination Response function a b s t r a c t Huge quantities of wastewater generated from municipalities need to be disposed off at regulated rates in non-edible crops viz. aromatic and medicinal plants to avoid food chain contamination and protec- ting the valuable natural resources. For finding optimum loading rates, an experiment was conducted in lysimeters during 2007–2010 on a sandy loam soil taking 5 irrigation depth:cumulative pan evaporation water regimes (irrigation at 0.6, 0.8, 1.0, 1.2 and 1.5 ID:CPE) of primary treated wastewater, groundwater and their conjunctive use and studied their effects on the herbage yield, essential oil yield, accumulation of heavy metals in lemon grass (Cymbopogon flexuosus). Averaged over water quality, herbage yield, dry biomass and essential oil yield varied from 10.11 to 13.68; 3.02 to 3.99 kg m -2 and 53.6 to 70.1 mL m -2 and were 43, 32 and 30% higher at 1.0 ID:CPE compared to 0.6 ID:CPE, respectively. The yields obtained at 1.0 and 1.2 ID:CPE were at par but significantly reduced with further wetter irrigation regime of 1.5 ID:CPE. Similar yields of lemon grass were obtained at various irrigation regimes of wastewater alone or in conjunction with groundwater and on an average were significantly (16%) higher than the sole use of groundwater. Concentrations of Cd, Cr, Ni and Pb in the herb ranged from 1.54 to 1.85, 3.27 to 4.04, 4.35 to 5.58 and 3.53 to 4.46 mg kg -1 , respectively at different irrigation regimes. The accumula- tion of heavy metals was the maximum in wastewater irrigated lemon grass which got reduced with conjunctive mode and the least with groundwater irrigation. However, heavy metal concentrations in essential oil were not influenced by the water application rates and water quality. In essential oil, Cd was in traces whereas average Cr, Ni and Pb concentrations were 0.14, 0.10 and 0.04 ppm, respectively. Heavy metal concentration both in herb and essential oil were well below the critical or permissible limit. With wastewater irrigation, there was a significant improvement in soil fertility status. Heavy metals started accumulating in soil but were well below the threshold level to reduce the crop growth. The results demonstrated that lemon grass could be successfully grown using primary treated municipal wastewa- ter alone or in conjunction with groundwater at 1.0–1.2 ID:CPE for achieving higher crop productivity without contamination of the end product – the essential oils. © 2013 Elsevier B.V. All rights reserved. 1. Introduction With increasing fresh water use by the remunerative sectors like municipalities and industries, the availability of water for agri- culture is projected to reduce drastically. This in turn means that ∗ Corresponding author. Present address: Water Technology Centre, IARI, New Delhi 110012, India. Tel.: +91 9416974140; fax: +91 11 25846790. E-mail addresses: khajanchi@iari.res.in, khajanchilal65@gmail.com (K. Lal). 1 Present address: Agricultural Scientist Recruitment Board, KAB I, Pusa, New Delhi 110012, India. larger volumes of wastewater are expected to be generated in the coming years. The total sewage generation from Class-I cities and Class-II towns of India is about 38,254 MLD, of which only 11,787 MLD (i.e. about 35%) is treated. Thus most of the sewage is largely let out untreated into either groundwater or natural drainage sys- tem thereby causing water pollution (CPCB, 2009). Land application of wastewater for irrigation is considered to be a safe and low cost wastewater disposal strategy with many profits including conser- vation of water, supplementing water supplies for irrigation and the use of nutrients in the wastewater for productive purposes (Lopez et al., 2006). Wastewater is source of livelihood and increas- ingly used for irrigating vegetables, fruits, food grains and fodder 0926-6690/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.indcrop.2013.01.004