India is endowed with rich wealth of medicinal and aromatic plants, but despite the rich heritage of knowledge on the use of plant drugs, little attention had been paid to grow them as field crops in the country till the later part of the nineteenth century. The folk medicine is based on empirical knowledge and utilizes a large proportion (25-60%) of local plant species in the various regions, as well as many animals and some minerals (Singh et al., 2008). Though India has been a pioneer in the production of several essential oils, the Indian herbal industry faces problems in the procurement of raw material. A solution to the problem could be achieved by the cultivation of medicinal and aromatic plants (Vijaya Lakshmi, 1999). The 960 traded medicinal plant species, 178 species are consumed in volumes exceeding 100 million tons per year, with their consolidated consumption accounting for about 80% of the total industrial demand of all botanicals in the country. Analysis of these 178 species by their major sources of supply reveals that 21 species (12%) are obtained from temperate forests, 70 species (40%) are obtained from tropical forests, 36 species (20%) are obtained largely or wholly from cultivations/ plantations, 46 species (25%) are obtained largely from road sides and other degraded land uses and the remaining 5 species (3%) are imported from other countries. According to the report of the World Health Organisation (WHO), a large population of the world relies on the traditional systems of medicines, largely plant based to meet their primary health care needs. India at present exports herbal materials and medicines to the tune of Rs.3000 crores during 2005 and expected to doubled. The Chinese export based on plants including raw drugs, therapeutics and other is estimated to be around Rs.18,000- Rs.22,000 crores. In view of the innate Indian strengths which interalia include diverse eco-systems, technical and farming capacity and a strong manufacturing sector, the medicinal plants area can become a huge export opportunity after fulfilling domestic needs.

All India production of medicinal and aromatic plants has shown an increasing trend from 2001 to 2011 (Figure 1) and recorded more than 300% over the period in terms of total area and production. However, in the case of Tamil Nadu state area under medicinal and aromatic plants was very small (10000ha.) with an annual production of about 61100 tons (2011, GOI, www.data.gov.in). A part from requirement of medicinal plants for internal consumption, India exports crude drugs mainly to developed countries, viz. USA, Germany, France, Switzerland, UK and Japan, who share between them 75 to 80% of the total export of crude drugs from India. The annual demand of botanical raw drugs in the country has been estimated at 3,19,500 MT for the year 2005-06. (Ved and Goraya, 2007). An import has been found to be a major grey area as adequate record keeping mechanism is not in place. Consolidation of species-wise data in respect of raw drugs harvested from wild (forest areas) obtained from 9 states, representing more than 52% of the forest area of the country, adds up to 1,20,000 MTof botanicals per annum. There are hundreds of valuable species of herbs growing in Nilgiris (Magesh and Vanya, 1999; 2008).Since the Nilgiris is subjected to major land degradation process of soil erosion due to steep land slope (Singh et al., 2000; Subhash et al., 2011), information on the extent of soil erosion, occurring due to the cultivation of medicinal and aromatic plants is important and alternate land use system or component of diversified land use system should address this problem. The natural resource degradation is the serious problem in the Nilgiris (Anonymous, 1988) due to steep slopes and high intensity of rainfall and this leads to accelerate the runoff and resulted in enormous soil erosion. Thus it is high time to check the land use and alter it in such a manner, which can provide more cover to land mass. Therefore, this study was aimed to test the natural resource conservation efficiencies and economics of different medicinal and aromatic plants on marginal and small land holdings of hilly areas.

Figure 1 Area and production of medicinal and aromatic plants

2Materials and Methods

The mean soil loss and runoff for the project period (1998-2001) is presented in Figure 2. It was observed that the soil loss under the cultivation of Digitalis, Mentha, Rosemary and Geranium is below the permissible limit (5t/ha) in the study area. However, soil loss was maximum under Thyme (16.4 t/ha) followed by Cineraria (9.5 t/ha) which is due to the fact that poor canopy cover and long-time taken for establishment. The lowest average annual soil loss and runoff was observed from Digitalis followed by Mentha, Geranium and Rosemary due to their rapid establishment and better canopy cover. It is interesting to note that in case of Mentha even with poor canopy and less biomass production due to frost effect during third year onwards, soil loss and runoff was towards minimum side due to effective soil binding by runnersover the soil surface. In general, harvesting of these crops was done at the onset of North-East monsoon (October) which produces high runoff but less soil loss since no soil disturbance occurred due to weeding and hoeing operations. During the South-West monsoon, soil disturbances are more due to weeding and hoeing which induce more soil loss. Less runoff during South-West was attributed to less intensity storms during the study period. Therefore, among the six treatments digitalis, cineraria, rosemary and geranium was found to be best in terms of soil erosion and runoff control in the study area. Further the nutrients loss was decreased from second year onward due to low soil loss and run off. The pH not affected and EC also did not shown very much difference across the treatments at the end of the project.

Figure 2 Soil loss (t/ha.) and runoff (%) in the treatments

Relative soil and water conservation efficiencies of selected species are depicted in Figure 3. The Soil and Water Conservation Efficiency varied from 39.1 to 97.2%. Whereas Relative Soil and Water Conservation Efficiency (RSWCE) in the case of Digitalis, Mentha, Geranium, Rosemary and Cineraria was observed viz. 97.2,90.5,90.0,91 and 39.1%, respectively. Almost, zero in the case of Thyme medicinal plant. Based on economic criteria order of medicinal plants profitability was observed that Digitalis, Cineraria, Rosemary had 1:9.4, 1:4.2 and 1:2.5, respectively higher BCR followed by Geranium, Thyme and Mentha. 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. Runoff and soil loss under Geranium was very high in the first year due to late establishment of the plants while during the second and third years, it was less and comparable to runoff and soil loss under Mentha.

Figure 3 Relative soil conservation efficiency

The economic value of Geranium is better than Mentha because of its very high oil price and wider uses in perfumery industry. The nutrient loss was low and fertilizer uptake also was less as compared to other crops grown in the study area.

3.4 Cost and benefit stream

The actual expenditure incurred from land preparation to sale of produce was taken into account while generating of cost stream. The farm gate price was multiplied with total production of each species and gross return was worked out. The project life was assumed eight year and accordingly cost benefit analysis was carried out. The economic analysis assumes the economic values of the medicinal and aromatic plants to be a function of investment, market value, non market value benefit sharing measure.

3.5 Economics of selected medicinal plants

The economic analysis was carried out by assessing the project life 12 years and at different rate of discounts, BCR, NPW and IRR were calculated  (Table 1). Based on economic criteria NPW and BCR of different species were observed to be T6>T3>T2>T1 order. The T4 and T5 were found to be uneconomical in the experiment carried out. Based on payback period also same trend was observed and at the same time these were also less effective interims of soil conservation. The IRR again has depicted the same picture as T6>T3>T2>T1. This has indicated theT6>T3>T2>T1 species were economically viable and has established the relationships that higher the yields, higher the economics returns. Therefore, digitalis, Cineraria, Rosemary and Geranium may be the viable proposition for sloppy area of Nilgiris, Tamil Nadu.

Table 1 Economics of different medicinal and aromatic plants (1999 to 2007)

3.6Scoring of usefulness of medicinal and aromatic plants

The index was developed using 0-3 point scoring. This index helps to the farmers, policy makers and researchers to make investment decisions and policy for medicinal an aromatic plants in the study area. Therefore based on the Table 2, it was revealed that Rosemary (26.37%), Digitalis (26.22), Cineraria (25.35, followed by Mentha (25.24%) and Geranium (23.37%) and Thyme (17.76%) scores obtained and indicating the usefulness of the respective species. The result clearly demonstrates the ranking of the species predominantly preferred by the stakeholders.

Table 2 Scoring of usefulness of medicinal and aromatic plants (1-3 Scale)

Policy Implications and conclusions The valuation exercise highlights that the inclusion of the perceptions of various stakeholders while valuing medicinal plants helps to prioritize species based on a broader framework of utility of the plants. The Soil and Water Conservation Efficiency varies from 39.1 to 97.2 percent, suggesting that all medicinal plants were not effective from conservation point of view. Whereas Relative Soil and Water Conservation Efficiency (RSWCE) in the case of Digitalis, Mentha, Geranium, Rosemary and Cineraria was observed viz. 97.2,90.5,90.0,91 and 39.1 percent, respectively. RSWCE was almost, zero in the case of Thyme medicinal plant. Based on economic criteria order of medicinal plants profitability was Digitalis, Cineraria, Rosemary had 1:9.4, 1:4.2 and 1:2.5, respectively higher BCR followed by Geranium, Thyme and Mentha. 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. It is desirable for a country to have an equal emphasis on conservation and market appropriation of medicinal plants. The results of this study show that the soil conservation values of medicinal plants increase when benefits are shared with a community. Some of the measures to encourage benefit sharing are promotion of contractual agreements between indigenous communities and the pharmaceutical industry that will ensure an assured market for the indigenous community and assured quantum and quality of resource to the end user; designing and implementing in situ and appropriate ex situ conservation activities that promote development of endemic medicinal plants (Mollik et al 2010). Digitalis, Geranium and Rosemary are the good options for alternate/diversified land use system as well as a cover crop, intercrop and vegetative barrier in Nilgiris among the selected species as regards to their soil conservation value and economic values. Mentha also could be the option for cover crop / intercrop for initial two years of establishment of any perennial plantation in the area. These species may hold promise in rehabilitating degraded / waste lands and will provide a value added land use system in watershed management programmes.

Vijay Lakshmi K., 1999, Cultivation of medicinal plants and contract farming. Plant Hort. Tech., 1:39-41