Distribution and Origin of Iron Oxides in Soils over Limestone

[Resumen] Se pretende conocer la distribuci6n y el origen de los compuestos de hierro en suelos formados sobre calizas en Galicia. Predominan las formas minerales de hierro, encontrando en la fracción arena magnetita, goethita y/o hematites y excepcionalmente ilmenita, que se consideran heredadas del material de partida. En lámina delgada se observaron goethita y hematites como granos aislados, constituyendo nódulos e integrados en fragmentos de caliza. En la arcilla, trazas de goethita están presentes en casi todos los perfiles; s610 en uno de ellos la hematites es el único 6xido de hierro. La goethita puede haberse formado tanto por neoformaci6n como por microdivisi6n a partir de las fracciones gruesas, siendo este último fen6meno el que ha originado la hematites de la fracci6n arcilla. En dos perfiles la goethita va acompañada de magnetita y se discute la posible existencía y formaci6n de maghemita.[Abstract] Iron distribution in soils formed over limestone of Galicia is studied an the origin of the different iron forms is established. Organic iron is very scarce and mineral iron components dominate. Magnetite, goethite and / or hematite, less cornmonly ilmenite, are found in the sand fraction; they are considered as interited from the parent material. In polished sections goethite an hematite appear as single grains, nodules and il1corporated into limestone fragments. In the clay fraction, traces of goethite are present in aH except one of the profiles where only traces of hematite are indentified. Neoformation and microdivision from coarse fractions can act in the genesis of goethite; only microdivision is considered as the origin of hematite. Magnetite accompanies goethite in two profiles; the possible presence of maghemite and its origin is also discusse

Indicadores de la estabilidad y madurez del compost

The authors specially thanks to Ediciones MUNDI-PRENSA by the authorization to include this archive of the published book, in the Institutional Repository DIGITAL CSIC https://digital.csic.esRED ESPAÑOLA DE COMPOSTAJE (REC) (SPANISH COMPOSTING NETWORK) funded by the Spanish Ministery of Science and Innovation as well as the Ministery of Environment. http://www.recompostaje.com CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS (CSIC). http://www.csic.e

Comparación de la estabilidad estructural de suelos de prado y cultivo

6 páginas, 4 figuras, 2 tablas, 14 referencias. Trabajo presentado al citado Simposio, Área temática 1: Calidad vs degradación de los suelos por actividades antrópicas, celebrado del 6-7, julio, 2005, en Madrid, España.[ES]: Se comparan las propiedades estructurales de dos suelos de la zona templado-húmeda española desarrollados sobre granito, dedicados a prado permanente y cultivo, a fin de valorar el impacto del tipo de manejo sobre la calidad estructural. El suelo de prado presentó unas propiedades estructurales más favorables, tales como una menor densidad aparente y mayor porosidad, un mayor tamaño medio de agregados, y una mayor estabilidad de los agregados frente a la agitación mecánica en agua y frente a la acción de la lluvia simulada. Esta mayor estabilidad estructural del suelo de prado se relaciona con su mayor contenido de materia orgánica (MOS). Asimismo, el suelo de prado presentó una mayor actividad microbiana, según se deduce de los valores más altos de respiración en experimentos de incubación, en comparación con el suelo de cultivo. El suelo de prado también presentó los valores más elevados de cociente respiratorio (C-CO2/C orgánico total), de lo que se deduce que la MOS del suelo de prado es más accesible a la degradación microbiana. Sin embargo no se observaron diferencias significativas entre la mineralización del carbono orgánico del suelo disgregado (<1mm) y de agregados intactos del mismo suelo (5-1 mm). Los resultados de este trabajo ponen en evidencia la necesidad de mantener niveles adecuados de MOS a través de enmiendas o reducción del laboreo.[EN]: We compared the structural properties of two neighbouring soils from the NW of Spain in order to evaluate the effect of management on structural quality. The soils were developed on granite under a warm and humid climate but differed in land use (pasture and cultivation). The pasture soil had more favourable structural properties than the cultivated soil, showing lower bulk density, higher porosity and water retention, higher mean aggregate diameter and aggregate stability against mechanical agitation in air and water, as well as lower soil loss under simulated rainfall. This increased structural stability of the pasture soil could be attributed to its elevated organic matter (OM) content. More C-CO2 was also released by OM mineralization in laboratory incubated pasture soil samples than in culture soils, due to higher microbial activity. Respiratory quotient (C-CO2/Corg total) was also higher in the pasture soil, thus indicating that the OM is more accessible to microbial decomposition. Nevertheless no significant differences were observed between organic C mineralization in disturbed ground soil <1 mm and undisturbed 5-1 mm aggregates. The overall results demonstrate the need to maintain adequate levels of OM by means of organic amendments or tillage reduction.Peer reviewe

The Spanish Society of Soil Science: Main projects and activities developed during the last years

The Spanish Society of Soil Science (in Spanish: Sociedad Española de la Ciencia del Suelo, SECS) was founded in 1947 by the Spanish National Research Council (CSIC) to promote cohesion and collaboration between soil science professionals, and with an innovative spirit and a willingness to serve the society. The objectives are: to promote the study, knowledge, research and protection of the soil; to spread, from a scientific point of view, the role played by the soil in favour of society, through ecosystem services such as the production of food and raw materials; The SECS also focus on the protection of other habitats and the conservation of our archaeological heritage; and to preserve knowledge of the soil, its management and use, both from the production and environmental point of view, leading to the optimization of its capabilities. The activities and services of the SECS are accessible on the web site www.secs.com.es, which is continually updated. In this contribution, we will show some examples of recent projects and activities developed by the SECS such as: the edition of the Spanish Journal of Soil Science (SJSS) since 2011; books like the white book on “Tratamiento del suelo en los libros de texto de ESO y Bachillerato en España” available in http://www.secs.com.es/archivo/libro-suelo.pdf, in which the term “Soil” is analysed in many secondary school books (152) in the Spanish education system; conferences, courses, exhibitions, expositions, calendars, the comic “Vivir en el suelo” in diferent languages, and diverse material to promote and disseminate the importance of the soil to the society; and last but not least, the Multingual Soil Science Dictionary (Spanish, Catalan, Gallician and Potuguese with translations in English and French (in process)) available online: http://cit.iec.cat/GLOSECS/inici.html. The promotion of student teams for soil science contests, the SECS Award to attend the Simposio Latinoamericano de Enseñanza y Educación en Ciencia del Suelo (SLCS, Quito, 2016) and other activities, such as incentives for young students, are also some of the strategies to promote the soil, together with an annual award to the best PhD thesis supervised by SECS members. These and other examples will be shown during the session with the main aim of exchanging ideas among soil societies to promote the soil. Access in www.secs.com.es.Peer Reviewe