Las Saladas del sur de Monegros : facies, régimen hídrico y estado actual

Los humedales son lugares de interés prioritario en las políticas ambientales orientadas a la conservación de hábitats singulares. Los humedales de medios áridos descritos en otros países suelen estar en áreas desérticas de África, Asia, Australia o las Américas, mientras que en Europa tienen una representación muy escasa. Las saladas de Bujaraloz-Sástago, objeto de esta Tesis, constituyen una de las poquísimas muestras de este tipo de hábitats en Europa; su conservación está amenazada por la transformación en regadío de la plataforma endorreica donde se ubican. En estos humedales confluyen aspectos bióticos singulares con aspectos abióticos, no menos interesantes por estar menos estudiados. La valoración de las saladas exige el conocimiento de dichos aspectos y su divulgación, incluso entre los responsables de la gestión del territorio. El objetivo de esta Tesis ha sido estudiar las saladas del sur de Monegros mediante datos de campo y de satélite disponibles, extrayendo información retrospectiva acerca de sus facies y de su estado hídrico. Para ello (i) se han tratado imágenes Landsat desde 1985 hasta 2000, utilizando las escasas observaciones de agua disponibles; (ii) se han integrado observaciones de campo, actuales y de otros autores, con la información suministrada por las imágenes de satélite. Con ello se han discriminado y catalogado cinco facies dentro de las saladas, cuyo seguimiento permitiría conocer la posible alteración derivada, por ejemplo, de la instalación de los nuevos regadíos; (iii) se ha avanzado en el conocimiento del régimen hídrico de las saladas, por un lado explorando su comportamiento frente a la precipitación y la evapotranspiración, y por otro lado actualizando el balance hídrico en la plataforma y en varias saladas seleccionadas; (iv) por último, se han evaluado los cambios en las saladas en las últimas décadas y su estado actual estableciendo índices que permiten cuantificar las observaciones y sistematizar su estudio. La Tesis deja constancia del estado actual de las saladas y de su régimen hídrico; además, la metodología propuesta para ambos estudios permite integrar nuevos datos. Estos pueden surgir del avance de la transformación del territorio o de nuevos criterios introducidos para valorar las saladas. También se podrían incorporar observaciones sobre los efluentes de riego, parámetros edáficos o topografías actualizadas, si se desea afinar el balance hídrico. El reconocimiento de humedales es una tarea de interés internacional, por ello hay muchos estudios que emplean la teledetección como herramienta básica de trabajo. En el sur de Monegros, las imágenes de satélite adquiridas para otros estudios combinadas con las observaciones de agua existentes han suplido parcialmente la falta de alguna institución interesada en reemprender el seguimiento del agua de las saladas. Todo ello, junto con los datos del estado actual de las saladas tomados en la limitada campaña de campo, se ha incluido en un sistema de información geográfica. Éste ha servido para aglutinar y contrastar observaciones dispersas e inconexas, de diferentes fuentes, y algunas de gran valor histórico. Queda abierta la tarea de completar y continuar esta labor, pero de momento el registro aquí presentado es el único disponible de las últimas décadas en la historia de estos humedales. El conocimiento de las saladas, la divulgación de sus valores y su reconocimiento oficial están dificultados por circunstancias como: el vacío legal existente para calificarlas como patrimonio geológico, cultural o natural; la falta de información para su valoración como humedales salinos singulares de importancia internacional; y el descrédito en su entorno social.Unpublishe

Edaphic and geomorphic evidences of water level fluctuations in Gallocanta Lake, NE Spain

The pedological implications of lake water level fluctuations are complex, especially in lake margin, where topographical, hydrological, and sedimentary conditions are most variable. Lake water level fluctuations generate landscape elements, which provide insights into the processes involved in soil development and the extent of the zones affected by flooding/desiccation. Coupling information from detailed geomorphological inspections in the field, the mapping of the lakeshore, and the pedogenesis of each landscape element can provide a better understanding of these relationships, which was used to study the saline Gallocanta Lake, NE Spain, a semiarid intramontane lacustrine system that undergoes significant and rapid water level fluctuations. Geomorphic classification of the lake margin forms and environments served as a guide for soil sampling. The geomorphological survey revealed high diversity and contrast in the lake margin environment, from shores affected by coastal erosion to zones characterized by progradation/aggradation. Two soil toposequences and 11 pedons that were on different geomorphic units were studied on two margins of the lake. Following gradients in elevation, moisture, and salinity, soils showed a succession of Inceptisols to Aridisols, with Mollisols developed at intermediate positions and Aquic soils at the lake floor and southern shore. Soils had a sandy, loamy texture and a predominantly carbonatic composition, high variation in CCE (mean = 37%), texture, and coarse fragments throughout the soil profiles. Soil salinity was the highest at the lowest topographic position and in the upper soil horizons, where mean ECe = 188.6 dS m− 1 at 25 °C. In addition, the highest organic matter (6%) and gypsum (34%) content occurred at the lake floor. Soil color characteristics and concentrations, and depletions of Fe and Mn indicated redox changes associated with soil water saturation under carbonate and or saline conditions. Macro and micromorphological features of oxidized and reduced horizons indicated the alternation between palustrine (reduced) and non-palustrine (detrital, emerged, oxidized) events at different geomorphic and topographic positions, from the lake floor up to 7 m above it. Pedogenesis inferred and the littoral/submerged forms located at permanently emerged areas confirmed the past and present trend towards the desiccation of the lake. This study has improved our understanding of how soils form and develop within the context of geomorphic units, and can be used in making land-use decisions in the protected reserve and agricultural surroundings of the lake.This article is a result of the research project AGL2012-40100 funded by the MINECO and is a contribution to Andalusian Research Group P.A.I. RNM-328. We acknowledge the data provided by the Spanish Meteorological Agency (AEMET). E. Luna was financed by a fellowship from the Government of Aragón, Spain. The 2006 orthoimages and LIDAR data were supplied by the National Geographic Institute of Spain (Instituto Geográfico Nacional)

Late Quaternary pedogenesis of lacustrine terraces in Gallocanta Lake, NE Spain

Transitional areas of lake margins are complex environments whose evolution is strongly controlled by flooding frequency and persistence. The edaphic development of lacustrine marginal environments can be reconstructed by combining detailed geomorphological analysis with a systematic edaphic study of toposequences. This approach has been applied to a set of recent lacustrine terraces in the downwind palustrine area of the Gallocanta saline lake, located in a semiarid area in NE Spain. Up to five terraces, from 1.6 to 4.5 m above the lake bottom, have been identified and mapped using stereo photointerpretation and airborne LiDAR data. Several cycles of water level fluctuations, as part of a general trend towards lake desiccation, have generated stepped terrace levels. The soils of these terraces have different morphological characteristics and provide evidences for the Gallocanta paleolake being larger than that of the present day. The soils have a sandy loam texture with variable clay content (1% to 46%) and a predominantly carbonate composition (mean = 26%). The soils are developed in a sequence of lacustrine carbonate-rich (mean = 37%) fine-grained gray layers overlaying detrital (mean = 51% gravels) and frequently erosive, carbonate-poor reddish layers. The pedogenesis of the downwind palustrine area is mainly characterized by poorly-developed carbonate accumulations and common redox mottles associated with water level fluctuations in the lake, which continuously rejuvenate or truncate the soils. Integrating pedological and geomorphological features provides insight into recent complex lacustrine and soil forming processes and facilitates management strategies and plans for this protected saline environment.This article has been funded by the Spanish Ministry of Economy and Competitiveness (MINECO) under projects AGL2012-40100 and PCIN-2014-106, by the Spanish Research Council (CSIC) under the project i-COOP-2016SU0015, and supported by the Andalusian PAI Research Group no. RNM-328. E. Luna was financed by the fellowship B087/13 from Aragón Government, Spain. Orthophotographs and LIDAR data were supplied by the Spanish National Geographic Institute (Instituto Geográfico Nacional). Rainfall data from Tornos were provided by the Spanish Meteorological Agency (AEMET) after contract no. L2 990130734

Assessment of soil fauna footprints at a rehabilitated coal mine using micromorphology and near infrared spectroscopy (NIRS)

Soil micromorphology in thin section and near infrared reflectance spectroscopy (NIRS) are useful techniques for assessing the participation of soil macrofauna in the formation of aggregates and soil structure. The purpose of this study was to use micromorphological analysis and NIRS techniques to assess the role of soil fauna in the recovery of soil aggregates and in the modification of soil microstructure in a chronosequence of rehabilitated areas at Cerrejon coal mine (La Guajira, Colombia). 64 soil samples were taken from rehabilitated areas (from 1 to 20 years ago) and from natural dry tropical forests Soil macroaggregates were subdivided into three categories: biogenic (BA), physical (PA), and non-aggregated soil (NAS). 32 samples were used for NIRS analysis, while ten thin sections of resin-impregnated soil blocks were micromorphologically analyzed. Principal component analysis of NIRS spectra showed a clear separation between BA, PA, and NAS. Likewise, an increase in BA was observed in the intermediate and advanced stages of rehabilitation. Respect to the micromorphological features, there was a clear change from a matrix of silt-sized quartz, unaccomodated peds, and unstructured materials with non-existent biogenic activity at the 2-year site to the formation of consolidated aggregates, more homogenized soil and increased biological activity at the 20-year site. Soil biological activity, principally the footprint of macrofauna, was recognized using the two techniques as well as at both the micro- and macro-morphology scales. These results reveal how the rehabilitation program being undertaken at Cerrejón mine is promoting the soil macrofauna population and associated bioturbation.This study was supported by a COLCIENCIAS grant, Colombia (Code: 1116-569-34827) and “Vicerrectoría de Investigaciones Extensión y Proyección Social” from Universidad del Atlántico

A Heritage Agronomic Study as a Database for Monitoring the Soil Salinity of an Irrigated District in NE Spain

This article presents and reviews the soil salinity data provided by a rescued vintage agronomic report on an irrigated area of 35,875 ha located in the center of the Ebro River basin, in the NE of mainland Spain. These data come from a soil sampling campaign conducted from May to the first half of July 1975 for the purpose of delineating saline and non-saline soils. The agronomic report was produced in response to demands from farmers to combat soil salinity, and represents the state of the art in those years for salinity studies. Our paper presents the scrubbed soil salinity data for this year, checking their consistency and locating the study sites. The main finding is the unearthing of this heritage report and the discussion of its soil salinity data. We show that the report supplies an assessment and a baseline for further soil salinity tracking by conducting new measurements either by direct soil sampling or by nondestructive techniques, providing an estimate of soil salinity at different locations. This task is feasible, as shown in our previously published articles involving nearby areas. A comparison of the salt amount in the soil over the years would provide a means to evaluate irrigation methods for sustainable land management. This comparison can be conducted simultaneously with analysis of other agricultural features described in the report for the irrigation district in 1975.Publishe

A heritage dataset of soil and water salinity in Bardenas, Spain

This article presents the results of soil and water analysis plus the plans —or “maps”— from the Report [1] issued 1974 on salt-affected soils in a new irrigation district located in the semi-arid Bardenas area of Aragón, northern Spain (Fig. 1). The survey was carried out by the now defunct Institute for Agrarian Reform and Development (i.e., IRYDA by its Spanish acronym). Work began in January 1972, with a preliminary reconnaissance survey on 53,000 ha using aerial photographs at a scale of 1:32,000 from the USAF photogrammetric flight of 1956-57 which covered almost the whole of Spain. Photographs from this flight are available on the Spanish aerial photograph viewer (https://fototeca.cnig.es/fototeca/). At that time, levelling for irrigation had not yet begun. This reconnaissance allowed the selection of an area of 32,300 ha (Fig. 1) with relevant salinity symptoms, like irrigated fields with irregular or no crop growth. A more detailed photo interpretation of the area was carried out at 1:12,000 scale from a flight in August 1971. The new irrigation district is fed by high quality water from the Pyrenees, but soon faced salinity problems that were well known to the farmers and echoed by the media [2, 3, 4] in an environment of great social concern about increasing agricultural production [5]. The Report, written in Spanish, is dated July 1974, but the soil profiles were described and sampled between April 1972 and March 1974. The Report [1] consists of two volumes, the first is a Memoria containing data from the surveys, laboratory analyses, pedological descriptions and some photographs of the soils and other land features of agricultural importance, as well as data and calculations for designing the drainage of selected plots. The second volume consists of five folded plans: a) location of the surveyed area at the scale of 1:200,000, and four plans at the scale of 1:25,000, b) soil-geomorphologic units, c) soil units describing their characteristics, d) land use, and e) locations of the described soil profiles and other field observations. Taken together, these data, improved by our orthorectification, gives a picture of the salinity and other soil properties in this area. The reuse of the data for comparisons with the evolution of agriculture in subsequent years —especially soil salinity and sodicity— will help to evaluate the agricultural practices over the last fifty years, particularly after intensive land levelling and irrigation.Esta investigación ha sido posible gracias a la beca PID2021-127170OB-I00 financiada por MCIN/AEI/10.13039/501100011033 y por «ERDF A way of making Europe», y a la beca TED2021-130303B-I00 financiada por MCIN/AEI/10.13039/501100011033 y por «European Union NextGeneration EU/PRTR».SostenibilidadSalinidad Del SueloRegadioPublishe

El agua de las Saladas de Monegros Sur estudiada con datos de campo y de satélite

Publishe

Edaphic and geomorphic evidences of water level fluctuations in Gallocanta Lake, NE Spain

The pedological implications of lake water level fluctuations are complex, especially in lake margin, where topographical, hydrological, and sedimentary conditions are most variable. Lake water level fluctuations generate landscape elements, which provide insights into the processes involved in soil development and the extent of the zones affected by flooding/desiccation. Coupling information from detailed geomorphological inspections in the field, the mapping of the lakeshore, and the pedogenesis of each landscape element can provide a better understanding of these relationships, which was used to study the saline Gallocanta Lake, NE Spain, a semiarid intramontane lacustrine system that undergoes significant and rapid water level fluctuations. Geomorphic classification of the lake margin forms and environments served as a guide for soil sampling. The geomorphological survey revealed high diversity and contrast in the lake margin environment, from shores affected by coastal erosion to zones characterized by progradation/aggradation. Two soil toposequences and 11 pedons that were on different geomorphic units were studied on two margins of the lake. Following gradients in elevation, moisture, and salinity, soils showed a succession of Inceptisols to Aridisols, with Mollisols developed at intermediate positions and Aquic soils at the lake floor and southern shore. Soils had a sandy, loamy texture and a predominantly carbonatic composition, high variation in CCE (mean = 37%), texture, and coarse fragments throughout the soil profiles. Soil salinity was the highest at the lowest topographic position and in the upper soil horizons, where mean ECe = 188.6 dS m− 1 at 25 °C. In addition, the highest organic matter (6%) and gypsum (34%) content occurred at the lake floor. Soil color characteristics and concentrations, and depletions of Fe and Mn indicated redox changes associated with soil water saturation under carbonate and or saline conditions. Macro and micromorphological features of oxidized and reduced horizons indicated the alternation between palustrine (reduced) and non-palustrine (detrital, emerged, oxidized) events at different geomorphic and topographic positions, from the lake floor up to 7 m above it. Pedogenesis inferred and the littoral/submerged forms located at permanently emerged areas confirmed the past and present trend towards the desiccation of the lake. This study has improved our understanding of how soils form and develop within the context of geomorphic units, and can be used in making land-use decisions in the protected reserve and agricultural surroundings of the lake

Late Quaternary pedogenesis of lacustrine terraces in Gallocanta Lake, NE Spain

Transitional areas of lake margins are complex environments whose evolution is strongly controlled by flooding frequency and persistence. The edaphic development of lacustrine marginal environments can be reconstructed by combining detailed geomorphological analysis with a systematic edaphic study of toposequences. This approach has been applied to a set of recent lacustrine terraces in the downwind palustrine area of the Gallocanta saline lake, located in a semiarid area in NE Spain. Up to five terraces, from 1.6 to 4.5 m above the lake bottom, have been identified and mapped using stereo photointerpretation and airborne LiDAR data. Several cycles of water level fluctuations, as part of a general trend towards lake desiccation, have generated stepped terrace levels. The soils of these terraces have different morphological characteristics and provide evidences for the Gallocanta paleolake being larger than that of the present day. The soils have a sandy loam texture with variable clay content (1% to 46%) and a predominantly carbonate composition (mean = 26%). The soils are developed in a sequence of lacustrine carbonate-rich (mean = 37%) fine-grained gray layers overlaying detrital (mean = 51% gravels) and frequently erosive, carbonate-poor reddish layers. The pedogenesis of the downwind palustrine area is mainly characterized by poorly-developed carbonate accumulations and common redox mottles associated with water level fluctuations in the lake, which continuously rejuvenate or truncate the soils. Integrating pedological and geomorphological features provides insight into recent complex lacustrine and soil forming processes and facilitates management strategies and plans for this protected saline environment