Urban Soil: A Review on Historical Perspective

Abstract

By the end of the twenty-first century, the global population is likely to touch 11 billion and the importance of soils in catering ecosystem services, particularly in densely packed areas, will likely be more felt. Soils are the cultivating ground from centuries providing food to all living entities either directly or indirectly but, urbanisation rather anthropogenic activities possess manifold dramatic influence in its properties. In 1847, Ferdinand Senft first mentioned the term ‘anthropogenic urban soils’ in his soil science book, and from this, the concept of urban soil or anthropogenic urban soil came into existence (Lehmann and Stahr 2007). Before going deep into the historical perspectives concerning urban soils, we must first know its definition. From the start, pedologists or different schools of people have come out with different definitions of urban soil, depending on its influencing factors and taxonomical characteristics, but confusions exist up to now. With the progress of time the concept of urban soil modifies greatly with the inclusion of every regulating factors like transportation (road, railway networks), site disturbances (sealing of surfaces), constructional works (building), intensity of use (trampling, hydraulic pressure) engineering interventions (green roofing, avenue plantations) and majorly environmental changes (pollution, climatic anomalies) specifically in spatio-temporal basis. Studies on urban soil have been started long back, but most of them are just basic research and are based on an ecological point of view. The concept of urban soil was started in the 1960s by Zemlyanitskiy (1963) when he referred to highly disturbed soils of the urban areas as urban soils. Later, Bockheim (1974) described urban soil as ‘[s]oil material having a non-agricultural, manmade surface layer more than 50 cm thick that has been produced by mixing, filling, or by contamination of land surface in urban and suburban areas’. This concept was supported by future pedologists (Craul and Klein 1980; Craul 1992). By the end of the twentieth century, Effland and Pouyat (1997) suggested a new definition, where they explained that urban soils are relatively unaltered soils but subjected to urban environmental factors like atmospheric depositions. This concept has been immensely accepted by contemporary pedologists up to present (Lehmann and Stahr 2007; Morel et al. 2017). Lehmann and Stahr (2007) further classified anthropogenic soil into inner urban and extra-urban, depending on its administrative boundaries. According to another school of thought, the term urban soil is rather vague and used the term ‘anthropogenic soil’ which broadened the concept of human influenced soils in lieu with the previous concept of only densely human inhabited areas only (Evans et al. 2000; Capra et al. 2015). The International Committee on Anthropogenic Soils (ICOMANTH), on different periods, introduced and modified terminologies related to anthropogenic soils. But they did not acknowledge any eroded (physical or chemical) soil to be anthropogenic soil (ICOMANTH 2011). However, as anthropogenic soils carry forward all historical information’s regarding cultural practices, artefacts and properties anthropological soils can be designated as ‘golden spikes’ of the Anthropocene (Certini and Scalenghe 2011). The terminologies used over the years to describe anthropogenic soils are specified in Table 1.1 (Capra et al. 2015). To avoid confusion, it is worth mentioning that in this chapter, we are using urban or anthropogenic terms synonymously.