Effects of vegetation and physicochemical properties on solute transport in reclaimed soil at an opencast coal mine site on the Loess Plateau, China Qing Zhen a,c , Wenmei Ma b , Mingming Li e , Honghua He a,b , Xingchang Zhang a,b, ⁎, Yi Wang d a State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China b Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China c University of Chinese Academy of Sciences, Beijing 100049, China d State key Laboratory of Loess and Quaternary, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China e College of Environment and Planning, Henan University, Kaifeng, Henan 475001, China abstract article info Article history: Received 17 September 2014 Received in revised form 21 April 2015 Accepted 12 June 2015 Available online 24 June 2015 Keywords: Reclaimed soil Soil properties Solute transport BTC Vegetation Mine soils are often polluted and degraded. The objectives of this study were to assess the effects of soil properties and vegetation on soil solute transport in reclaimed soil at an opencast coal mine site on the Loess Plateau. Four reclaimed areas with different vegetation types were selected for the analysis of physical and chemical properties. The miscible displacement technique was used to obtain the breakthrough curves (BTCs) of NO 3 - ion transport in undisturbed soil columns, which were taken from the soil profiles of the dif- ferent sites. The chemical properties, such as total N, P, K and SOM, exhibited low contents, and the soil physicochemical properties showed high heterogeneity between different depths and different reclaimed areas. The structural stability index was less than 5%. The initial and entire penetration times were longer in the deeper layers than in the top layer. The BTCs of NO 3 - were fitted well by the deterministic equilibrium con- vection dispersion equation (CDE) model. Preferential flow and transport were found in the soil columns. The reclaimed soil had poor structure, and planting vegetation improved the physiochemical properties of the soil. The soil solute transport parameters exhibited high heterogeneity between different samples and were signifi- cantly correlated with soil bulk density and soil texture, which were highly influenced by vegetation and human activities. In the process of land reclamation, increasing the bulk density and selecting fine-textured soils could reduce the average soil pore water velocity and the dispersivity coefficient, thereby extending the solute penetration time. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Coal plays a leading role in the energy structure of China and contrib- utes greatly to China's economic development (Wang et al., 2006). However, coal mining activities, especially opencast mining, have caused serious damage to the environment, including the elimination of vegetation, permanent topographic changes, dramatic changes in the soil and subsurface geological structure and disruption of the surface and subsurface hydrologic regimes (Keskin and Makineci, 2009). Coal mining produces a large amount of stripped soils, coal gangue, tailings and other solid wastes, which are buried or deposited in piles, replacing a large area of arable land with bare ground. Mine soils are usually de- graded and are characterized by poor soil structure, high bulk density, low pH, low nutrient availability, low water holding capacity, low struc- tural stability and low biomass productivity (Asensio et al., 2013; Palumbo et al., 2004; Shrestha and Lal, 2006). Reclamation of these bare ground soils is necessary to minimize the risk of land degradation (Pedrol et al., 2010). Chemical, physical and biological properties are always selected as the main soil quality indicators and are monitored over time to determine changes in soil quality, i.e., improving, degrading, or sta- ble (Carter et al., 1997; Shukla et al., 2004a). Several authors have studied the degradation and reclamation of mined soils and suggest that the establishment of vegetative cover should be encouraged. The selection of appropriate vegetation and soil amendments is es- sential to stabilizing a bare area and remediating adverse physical and chemical properties (Asensio et al., 2013; Keskin and Makineci, 2009; Wong, 2003; Zhao et al., 2013). Shukla et al. (2004a) found that bulk density was the most discriminating factor and that water-stable aggregation was the most commonly measured soil at- tribute and the most dynamic soil quality indicator for reclaimed mine soils in southeastern Ohio. The authors also found that there were no significant differences in several soil properties, such as bulk density and SOC content, between undisturbed (unmined) soil Catena 133 (2015) 403–411 ⁎ Corresponding author. E-mail address: zhangxc@ms.iswc.ac.cn (X. Zhang). http://dx.doi.org/10.1016/j.catena.2015.06.009 0341-8162/© 2015 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Catena journal homepage: www.elsevier.com/locate/catena