Medicinal and aromatic plants for soil and water conservation: An economic analysis, Nilgiris, Tamil Nadu, India

Abstract

This study was carried out to examine the economics and soil and water conservation value of prominent medicinal and aromatic plants in the hilly areas of Nilgiris, Tamil Nadu during 1998-99 to 2004-05. The six species of medicinal and aromatic plants were planted in 15m × 5m plots on 15% land slope to assess the relative soil and water conservation efficiency and economics. The Geranium recorded highest average green biomass yield followed by Digitalis, Cineraria, Mentha and Rosemary. Runoff and soil loss was maximum under Thyme followed by Cineraria because of their poor canopy cover. The lowest average annual soil loss and runoff over the year was observed from Digitalis followed by Mentha and Geranium due to their quick establishment and higher canopy cover. The soil and water conservation efficiency varied from 39.1 to 97.2%. Whereas, relative soil and water conservation efficiency (RSWCE) of 97.2,90.5,90.0,91 and 39.1% in Digitalis, Mentha, Geranium, Rosemary and Cineraria, respectively and observed almost zero in the case of Thyme. Based on economic criteria order of medicinal plants profitability it was observed that Digitalis, Cineraria, Rosemary had 1:9.4, 1:4.2 and 1:2.5, respectively higher benefit cost ratio (BCR) where as Geranium has given higher internal rate of returns (IRR). However, IRR for Thyme and Mentha was almost negligible. Thus, RSWCE and Economic criteria does not follow the same pattern of preference of medicinal and aromatic plants. Eight years of the study suggest that Digitalis, Mentha, Geranium and Rosemary cultivation could be the viable proposition for a diversified land use system as well as for cover crop, intercrop and vegetative barrier in the Nilgiris for effective natural resources conservation. The economic analysis also found to be viable for cultivation of these plants in Nilgiris.