Enzyme activity indicates soil functionality affectation with low levels of trace elements.

The use of the soil can alter its functionality and influence the (bio)availability of any contaminants present. Our study considers two types of agricultural soils, rainfed and olive soils, managed according to conventional practices that apply contaminants directly to the soil (fertilizers, pesticides, fungicides, etc.) and receive contaminants from the atmosphere (traffic, industry, etc.); and a forest soil that is not subject to these agricultural practices. In this scenario, we consider a mixture of 16 trace elements (As, Ba, Be, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Se, Sb, Sn, V and Zn), since their interactions with the soil can produce synergistic and/or antagonistic effects that are not considered in most studies. We studied whether the content and (bio)availability of low concentrations of a mixture of trace elements affect the soil functionality in terms of the activity of some key enzymes We analysed the total, potentially and immediately available fractions, the soil parameters and soil enzyme activity. The results show that the functionality of the soils studied was affected despite the low concentrations of trace elements. The highest concentrations of total trace elements and available fractions were found in forest soils compared to the other two uses. Soil enzyme activity is best explained by the potentially available fraction of a mixture of trace elements and physico-chemical soil variables. In our study, pH, total nitrogen, organic carbon and fine mineral particles (silt and clay) had an influence on soil enzyme activity and the (bio)available fractions of trace elements.

Estudio de los suelos del entorno del Balneario de San Nicolás (Almería) / Study soil in the thermal environment of San Nicolás (Almería)

Las propiedades fisico‐químicas de los suelos que se encuentran en la parte superficial de las capas freáticas, juegan un papel muy importante en las características hidroquímicas de las aguas subyacentes, pues fenómenos como disolución, hidrolisis y procesos de oxido‐reducción de fracciones minerales y orgánicas de los suelos influyen de forma significativa en la composición de las mismas. Además, textura, estructura y materia orgánica del suelo son factores claves en la regulación del régimen hidrodinámico. En este trabajo analizamos las características edáficas de cuatro suelos muy significativos de los alrededores del Balneario de San Nicolás, ubicado en Alhama de Almería, Alpujarra Almeriense, situada a 450 msnm en la ladera norte de la Sierra de Gádor. Son suelos con escaso desarrollo, tipo AC, formados a partir de materiales sedimentarios constituidos por margas arenosas, calcarenitas, dolomías y yeso, los situados en las proximidades del Valle del Andarax, y por materiales de derrubios de ladera y pie de monte, con predominio de cuarcita, dolomías, calizas y calizas margosas, los situados en la Sierra de Gádor. Los suelos son carbonatados y están saturados, siendo el calcio el catión mayoritario. Presentan pHs básicos, bajo contenido en materia orgánica y texturas gruesas. Cuarzo, calcita, dolomita y yeso son los minerales más abundantes entre los no laminares, y son las micas los filosilicatos presentes en mayor proporción. El predominio de texturas gruesas y la perdida de estructura en los horizontes profundos son determinantes en el grado de infiltración. Se han incluido en las unidades Regosoles y Calcisoles (AU)

The physico‐chemical properties of soils adjacent to aquifers play an essential role in the hydrochemical characteristics of the underlying waters. Thus, phenomena such as dissolution, hydrolysis and oxide‐reduction processes of the mineral and organic fractions of soils may have a significant influence on the composition of these waters. Furthermore, soil texture, structure and organic matter are key factors regulating the hydrodynamic regime. In this work, the edaphic characteristics of four highly representative soils located in the thermal environment of San Nicolas in the Alhama de Almería municipality of the Alpujarra Almeriense region were analyzed. The area is part of the northern side of the Sierra de Gádor at an altitude of 450 masl. They are poorly developed soils, mainly AC profiles. Soils in the vicinity of the Andarax Valley are formed on sedimentary materials constituted by sandy marls, calcarenites, dolomites and gypsum, and those in the Sierra de Gádor developed on debris material from hillside and piedmont and mainly integrated by quartzite, dolomites, limestones and marly limestones. Soils are carbonated and saturated, with calcium being the major cation. They have basic pH values, low organic matter content and coarse textures. Quartz, calcite, dolomite and gypsum are the prominent minerals among the non‐laminar ones, and micas among the phyllosilicates. The predominance of coarse textures and the loss of structure in the deep horizons are decisive in their infiltration capacity. They were classified as Regosols and Calcisols (AU)