On-farm energy input-output and economic analysis of important essential oil-bearing Mint species in subtropical India

Abstract

Mint species are grown worldwide and known for their medicinal and aromatic properties however, studies on its energy assessment are very scarce. This study quantifies the energy input–output relationship of herbs and essential oil production of different mint species (M. arvensis, M. piperita, M. spicata, M. cardiaca and M. citrata) which were commercially grown in subtropical India. This study proposes for life cycle assessment and their effects on environment. The energy inputs and outputs were significantly varied with mints species. Results showed that mints essential oil production used more energy than herbs, and M. citrata utilizes the highest energy in both cases. Fire wood requirements for essential oil extraction accounts maximum (59.16 %) energy input. Mint herbs and essential oil yields were recorded higher in M. citrata (23.14 t ha⁻¹), and M. arvensis (143.2 kg ha⁻¹), respectively. Energy yields were estimated highest in M. cardiaca (herbs), and M. arvensis (essential oils), and required net calorific values were tested by automated advanced oxygen bomb calorimeter. Overall, M. arvensis showed the best results in energy production (0.07 kg MJ⁻¹), profitability (0.27), net return (17156.40 MJ ha⁻¹), and energy use efficacy (1.27) for mint herbs production. However, for essential oil production M. cardiaca performed well. This study revealed that mint herbs production was more energy efficient than essential oils extraction although essential oil production is fiscally secure.