No abstract

No abstract

The aim of the work described here was to understand the pedogeochemical signature of five rare earth elements (REEs; Ce, Nd, La, Y, and Sc) in vineyard soils in Campo de Calatrava (a unique territory with calcareous, volcanic and metamorphic rocks). The mean contents in surface horizons of Ce, Nd, La, Y, and Sc were 65.7, 32.0, 35.5, 18.8, and 13.9 mg·kg–1, respectively. In subsurface horizons the contents were Ce 62.8, Nd 31.1, La 35.7, Y 17.9, and Sc 14.4 mg·kg–1. The results show that mean contents of REEs in the area under investigation are in the order Ce > Nd > La > Y > Sc. Ce has a very high range, with a value close to 150 mg·kg–1. On the other hand, concentrations of Ce, Nd, Y, and Sc are higher in soils on volcanic material than in soils on nonvolcanic material, while only La values are lower in soils on volcanic rocks. The distributional maps of REEs in surface and subsurface horizons suggest that parent material and pedogenesis such as argillization and calcium carbonate accumulation are more important factors than the use of REE-based fertilizers, except in certain exceptional cases (consistent with a possible specific human impact after continuous fertilization).

No abstract

<p>Understanding the dynamics of plant populations and their relationship with the characteristics of the terrain (slope, texture, etc.) and with particular phenomena (erosion, pollution, environmental constrains, etc.) that could affect them is crucial in order to manage regeneration and rehabilitation projects in degraded lands. In recent years, the emphasis has been placed on the observation and assessment of microtopographic drivers as they lead to large-scale phenomena. All the ecological variables that affect a given area are interconnected and the success in unraveling the ecological patterns of operation relies on making a good characterization of all the parameters involved.</p><p>It is especially interesting to study the natural colonization processes that take place in Mediterranean areas with a high degree of seasonality, to whose climatic restrictions, the presence of pollutants and various anthropic actions, can be added. Over these degraded areas, we propose using a new tool, what we have come to call "<strong>pictorial transects</strong>", that is, one-dimensional artificial transects built from low-scale photographs (2 m<sup>2</sup>) taken along a line of work (transect) where you can see the points where ecological resources are generated, stored and lost, and their fluctuation throughout time. A derivative of these would be the "<strong>green transects</strong>" in which the green color has been discriminated using the open software Image I. It is an inexpensive, fast and straightforward pictorial method that can be used to research and monitor the spatial and temporal fluctuation of the potential input of resources (organic matter, water, fine particles, etc.) to the ecosystem.</p><p>The information obtained from pictorial transects not only refers to the measurement of the photosynthetic potential per unit area or the location of the critical points (generate, storage or sink of resources) but also makes it possible to monitor the specific composition of the plant cover. For an appropriate use of this methodology, the criteria to determine the direction and length of the different transects must be previously and carefully established according to the objectives proposed in the study. For example: a radial transect in a salty pond will give us information on the changes in the plant cover as we move away from the center and the salinity decreases. In the same pond, a transect parallel to the shore will give us information on those changes that occur in the vegetation that do not depend on the degree of salinity. There are some cases in which this method could be very useful, as in the natural colonization of a degraded mine site or to assess the progression area affected by allochthonous species or weeds in extensive crops.</p>

En el presente trabajo se estudió la relación entre las principales características del suelo que influyen en la retención de humedad (densidad aparente y porcentajes de arena, limo, arcilla, materia orgánica y carbonato cálcico) y la humedad gravimétrica a capacidad de campo (CC), punto de marchitez permanente (PMP) y capacidad de retención de agua disponible (CRAD) o agua útil de los horizontes superficiales de 101 suelos vitícolas de Castilla-La Mancha (España). Los suelos se describieron morfológicamente y se realizaron los análisis pertinentes de establecimiento de las principales propiedades de los mismos. La CC y PMP se determinaron con el método de placas Richards (aplicando -33 KPa y -1500 KPa, respectivamente) y la CRAD fue deducida por diferencia (CC-PMP). Del Análisis de Componentes Principales se deduce que dos componentes explican el 61,76% de la variabilidad de los datos (porcentaje de contenido en arena y densidad aparente). Las propiedades que mostraron una mayor relación lineal, estadísticamente significativa, con CC, PMP y CRAD fueron el porcentaje de arena (R= -0,68, -0,68 y -0,47) y de limo (0,5, 0,49 y 0,37) respectivamente. Se utilizóel programa Surfer para la elaboración de mapas de distribución espacial de propiedades del suelo.