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Environmental cost of using topsoil for brick-making
Journal
Environmental Scenario in India: Successes and Predicaments
Date Issued
2013-01-01
Author(s)
Kathuria, Vinish
Balasubramanian, R.
Abstract
Introduction The removal of topsoil for urban uses, and in particular for brick-making, is increasing rapidly due to the tremendous growth in urbanization and industrialization in many developing countries. Unfortunately, brick kilns are mostly situated on fertile agricultural land, as brick manufacturers need silty clay loam to silty clay soils with good drainage conditions. Quite often soils used in brickmaking have high fertility status and their opportunity cost is also high especially when the soil/brick-earth is removed from river basins with intensive agricultural production. Another important dimension to the problem is the depth over which the soil is removed frequently exceeds the agreed depth of soil extraction, which renders land unsuitable for agriculture. Under this backdrop, the main focus of this chapter is to quantify the agricultural impacts of topsoil removal for brick-making. The removal of topsoil has a direct impact on agricultural crop production via the reduced fertility status of soils. As the addition of organic matter in the forms of human and animal wastes and plant residues occurs only over the top layers of soil, removal of topsoil leads to loss of soil fertility. Therefore, the negative impact of topsoil removal is quantified in terms of the cost of replacing the nutrients lost. The quantification is important because while procuring brick-earth/soil, this cost is never considered, as this is a societal cost. The quantification of the cost of topsoil removal is carried out using a replacement cost approach (RCA) for Tamil Nadu, a southern state of India. The choice of Tamil Nadu is justified because the state is in the forefront of urbanization among all the states in India, with nearly 44 per cent of its population living in urban areas.1 Fast growing cities like Chennai, Madurai and other major cities in the state are witnessing steady growth in construction activities. As a result the Cooum River Basin around Chennai and the Tamirabarani River Basin in Tirunelveli and Tuticorin districts are the two major fertile agricultural areas facing serious challenges from brick industries. In order to compute the environmental cost of using topsoil, 60 soil samples - 30 from each region - are analysed from both types of fields, i.e. fields sold/leased land for brick-making, and virgin fields not exposed to excavation by brick manufacturers.