Economic valuation of agro forestry systems and quantification of ecological uses in Tamil Nadu

Traditionally, agroforestry is extensively practiced in India in the form of the shifting agriculture, a variety of cereal cropping systems, home garden systems, traditional plantation systems, etc. In recent times, many of these agroforestry systems have started breaking down for a variety of reasons. In many situations, high diversity based agroforestry systems have been replaced by low diversity simplified cash crop systems, and this is questionable in terms of sustainability. The paper argues for traditional ecological knowledge and to measure the social cost and benefit involved in agro-forestry in study area using Investment analysis, Sensitivity analysis of tree cultivation, descriptive statistics and Pearson product moment correlation (PPMC). The discounted social costs, returns, net worth for agri-silviculture system (teak+maize) were estimated to be Rs. 24208, 137457 and 113248 per hectare over the life time of teak trees. The Benefit Cost Ratio was 5.68 showing that investment in teak cultivation can be considered as substantial and economically justifiable. Internal rate of return was found to be 23% over the period. It showed that investment made in teak production is profitable, it could be seen that the intangible cost included cost of birds scaring only. It was higher in case of Teak since these crops provided shelter to birds, have a longer gestation period and they attract more birds. Intangible benefits are realized due to soil and water conservation, agricultural productivity of intercrops, nitrogen fixation, waste assimilation and carbon storage. In the socio-economic analysis, when carbon sequestration and soil water conservation benefits are incorporated, it provides very high NPVs for agri-silviculture system.