The combination of quarry restoration strategies in semiarid climate induces different responses in biochemical and microbiological soil properties Lourdes Luna a, *, Roberta Pastorelli b , Felipe Bastida c , Teresa Hernández c , Carlos García c , Isabel Miralles d,a , Albert Solé-Benet a a EEZA-CSIC, Estación Experimental de Zonas Áridas, Consejo Superior de Investigaciones Científicas, Carretera de Sacramento s/n, 04120 La Cañada de San Urbano, Almería, Spain b CREA-ABP, Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria, Centro di Ricerca per l'Agrobiologia e la Pedologia, Piazza D'Azeglio 30, 50121 Firenze, Italy c CEBAS-CSIC, Centro de Edafología y Biología del Segura, Consejo Superior de Investigaciones Científicas, Campus Universitario de Espinardo, 30100 Espinardo, Murcia, Spain d TECLIM, Centre de recherche sur la Terre et le climat Georges Lemaître, Université Catholique de Louvain, Place Louis Pasteur 3, Louvain-La-Neuve, Belgium A R T I C L E I N F O Article history: Received 25 November 2015 Received in revised form 5 May 2016 Accepted 10 May 2016 Available online xxx Keywords: Limestone quarry restoration Organic amendments Mulches Enzyme activities PLFA PCR-DGGE A B S T R A C T Mining activities generate loss of environmental and landscape quality, especially in arid and semiarid Mediterranean regions. A precondition for ecosystem reclamation in such highly disturbed areas is the development of functional soils with sufficient amount of organic matter. In a restoration experiment in limestone quarries in the Sierra de Gádor (Almería), SE Spain, several combinations of organic amendments (sewage sludge and compost from domestic organic waste) and mulches (gravel and woodchip) were tested and native plants (Anthyllis cytisoides, A. terniflora and Macrochloa tenacissima) were planted. After five years, the effect of each treatment on the soil chemical properties, basal respiration, four enzyme activities (dehydrogenase, urease, b-glucosidase and alkaline phosphatase) and the microbial community composition was analysed. Analysis of phospholipid fatty acids (PLFAs) and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprinting were used to analyse the microbial communities (bacteria and fungi). Undisturbed natural soils adjacent to the mining area were used as soil quality references. Organic amendments, particularly compost, improved soil chemical and biochemical properties as well as microbial biomass. However, the effects of mulch application did not show a clear trend with respect to soil functionality and did not increase the microbial biomass. Soils treated with sewage sludge and compost showed bacterial PLFA concentrations similar to those of reference soils, but compost treatments presented fungal PLFA concentrations that were much higher. Each combination of organic amendment and mulch was selective for a proper microbial community. Nevertheless, increases in soil functionality and microbial biomass were not related to changes in microbial diversity. After five years, the microbial properties of restored soils had not yet converged to values recorded in the reference soils. However, the combination of mulches and organic amendments, particularly compost treatment, is suggested to be beneficial for restoring degraded soils from quarrying areas because they stimulate microbial growth and activity, with positive implications for the increase in both soil fertility and quality. ã 2016 Elsevier B.V. All rights reserved. 1. Introduction The quality of landscape and environment is negatively affected by mining. Open-pit limestone mining is particularly harmful because of the type of extraction, which does not generate reject material. Thus, reclamation of these degraded lands must begin with an inert substrate with easily friable materials on steep slopes * Corresponding author. E-mail addresses: lourdes.lunaramos@gmail.com, lardani1984@hotmail.com (L. Luna). http://dx.doi.org/10.1016/j.apsoil.2016.05.006 0929-1393/ã 2016 Elsevier B.V. All rights reserved. Applied Soil Ecology 107 (2016) 33–47 Contents lists available at ScienceDirect Applied Soil Ecology journal homepage: www.elsevier.com/locate/apsoil