Contents lists available at ScienceDirect Geoderma journal homepage: www.elsevier.com/locate/geoderma Assessment of revegetation of an acidic metal(loid)-polluted soils six years after the incorporation of lime with and without compost Javier Pardo a , Pedro Mondaca a , Juan L. Celis-Diez a , Rosanna Ginocchio b , Claudia Navarro-Villarroel c , Alexander Neaman a, ⁎ a Escuela de Agronomía, Pontificia Universidad Católica de Valparaíso, Quillota, Chile b Facultad de Agronomía e Ingenieria Forestal, Center of Applied Ecology and Sustainability (CAPES), Pontificia Universidad Católica de Chile, Santiago, Chile c Instituto de Estadística, Universidad de Valparaíso, Valparaíso, Chile ARTICLE INFO Handling Editor: Edward A Nater Keywords: Aided phytostabilisation Natural attenuation Soil remediation Puchuncaví valley Ventanas industrial complex ABSTRACT The process of passive revegetation of chemically degraded soils through assisted remediation was assessed under field conditions 6 years after amendment application. In 2009, three treatments were applied: unamended soil (untreated), soil amended with lime, and soil amended with lime + compost. For each field plot, main soil physico-chemical characteristics were determined (pH, organic matter, moisture content at field capacity and exchangeable Cu), while plant colonist development was assessed (plant cover and aboveground biomass). The same evaluation was carried out in 2015. A single application of amendments maintains a neutral pH after 6 years. Thus, neutralization of the soil acidity was stable over time. In 2009, lime + compost was the best treatment for increasing the plant cover. Although the soil organic matter content decreases in year 6, plant cover remained stable over time in this treatment. Incorporation of both organic matter and lime was pivotal at the beginning of the revegetation process, allowing the creation of a potentially self-sustaining ecosystem. No maintenance and/or additional application of amendments was required. Aboveground biomass showed dif- ferences between years, possibly explained by changes in climate conditions between 2009 and 2015, and/or changes in nutritional conditions (soil fertility) and plant competition. Plant biodiversity in year 6 was similar for all treatments. The long-term results of plant cover show lime and specially lime + compost as promising amendments to revegetate polluted soils of the Puchuncaví Valley. 1. Introduction Environmental problems associated with the operation of metal (loid) smelters are a global concern (Ettler, 2016). This is the case of the biodiversity-rich coastal Mediterranean ecosystem of the Puchuncaví valley in central Chile, that was exposed to atmospheric depositions of sulphur dioxide (SO 2 ) and metal(loid)-rich particles from the Ventanas Industrial Complex, composed by a copper smelter and a thermal power plant from 1964 to 1992 (Folchi, 2006). During this period, soils sur- rounding the industrial complex accumulated metal(loid) at high con- centrations, and were acidified and strongly eroded, as a result of the loss of the native sclerophyllous vegetation cover (De Gregori et al., 2003; Ginocchio, 2000; Neaman et al., 2009). The loss of native vege- tation could lead to further environmental problems related to pollu- tion. For example, it could increase metal(loid) leaching and/or the resuspension of as a result of the metal-rich dust, possibly resulting in their ingestion by local population (Bierkens et al., 2011; Tordoff et al., 2000). As a result, revegetation is one option for reducing environ- mental risks associated to acidic and metal-polluted soils. Revegetation of chemically degraded areas has been evaluated using various processes including natural attenuation, which takes long time, and assisted revegetation by adding cost-effective and minimally in- vasive soil amendments reducing the recovery time of the plant cover (Adriano et al., 2004; Mench et al., 2006). In the last case, two options have been used for restoring plant cover once plant-growth restrictions have been removed/reduced from the site. The first is active re- vegetation, with seeding and/or transplanting of plant species (Alvarenga et al., 2008; Clemente et al., 2005). The second is passive revegetation, with development of plant colonists from the soil seed bank, seeds dispersed by natural vectors, and/or regeneration of re- maining plants (Álvarez et al., 2003; Conesa et al., 2007). Córdova et al. (2011) previously showed that plant cover and aboveground biomass were similar under active and passive revegetation regimes, in the Puchuncaví valley suggesting that plant cultivation was unnecessary for https://doi.org/10.1016/j.geoderma.2018.06.018 Received 4 January 2018; Received in revised form 7 May 2018; Accepted 19 June 2018 ⁎ Corresponding author. E-mail address: alexander.neaman@pucv.cl (A. Neaman). Geoderma 331 (2018) 81–86 0016-7061/ © 2018 Elsevier B.V. All rights reserved. T