Fertilización de base en un cultivo inicial de pecan con dos marcos de plantación de alta densidad

91-97The fruit of the pecan tree, Carya illinoensis Koch, is considered a very healthy food. In Argentina, pecan cultivation has been expanding rapidly but very little research has been conducted on pecan fertilization and planting systems. The objectives of this study were to characterize some physical-chemical and chemical properties in a pecan crop, and compare different basal fertilization (FB) treatments under two high density plantation frames (MP). Plantation was conducted in Villanueva (Buenos Aires province), on a Tapthoargic Hapludoll, with 10 x 10 m frames (real part: MR) and 8 x 8 m frames (staggered: TR). The experimental design was a split plot with four replications. The main plots were the two frames and the subplots were the different fertilization treatments: Compost (C), Phosphorus (P), slow release Nitrogen (N), and an unfertilized control (T). The determinations to assess the growth of pecan plants were: plant height and stem diameter. With regard to soil fertility, phosphorus fertilization and the addition of compost significatively increased the levels of Bray-P. The organic fertilizer treatment (compost) showed a significant increase in the height of the pecan plantation under the 8 x 8 m frame, which was not apparent in any case for the stem diameter, with a MP x FB significant interaction (P = 0.01) for height variation in the first year. The plantation frame with or without basal fertilization had no effect on pecan volume during the study period

Public health and heavy metals in urban and periurban horticulture

148-154The health effects of heavy metals can be complex and severe. Exposure to heavy metals has been linked with developmental retardation, various cancers, kidney damage, and even death in some instances of exposure to very high concentrations. Soils in urban and suburban areas are transformed by human activities, they are characterized by a strong spatial heterogeneity resulting from the various inputs of exogenous materials and the mixing of original soil material, and they often hold pollutants that may be a threat to human health. The objective of this work is to present a study of heavy metals occurrence in 33 urban and periurban soils dedicated to horticulture in Buenos Aires (Argentina). Total heavy metal content in soils (cadmium, chromium, copper, nickel, lead and zinc) was evaluated using Sequential Plasma Emission Spectrometer (ICP-ES). Data were analyzed using multivariate analysis showing a primary separation in two groups: eight sites with high contents of one or more of the analized heavy metals and the second group with lower levels of heavy metals. Maximum values of Cd, Pb, Zn and Cu in horticultural soils resulted problematic with reference to public health

Bioensayos de toxicidad aguda con Lactuca sativa en sedimentos contaminados del Río Reconquista en disposición final

p.179-185Se realizaron dos ensayos de toxicidad aguda con semillas de Lactuca sativa para evaluar la biotoxicidad en sedimentos contaminados y dispuestos del río Reconquista. Se aplicaron tres tratamientos: testigo arena (A); sustrato compuesto por arena-sedimento al 50 por ciento (AS) y sustrato 100 por ciento sedimento (S). Se midió número de plántulas, longitud radical y se observaron indicadores de fitotoxicidad. Hubo diferencia entre tratamientos en el número de plantas que emergieron (P menor que 0,02). Se observó necrosis en los cotiledones en AS y S. En el segundo bioensayos, a partir del extracto sedimento:agua 1:2,5 se trabajó con cuatro diluciones (1:1, 1:5, 1:10 y 1:25) y testigo de agua destilada. La longitud radical entre los tratamientos y el testigo fue significativa (P menor que 0,05) : X 7,24 mm para el extracto más concentrado, 11,91 mm para el más diluido y 13,79 mm para el control. Se estimó CE20 para una dilución de 1:13. La solución más concentrada se aproxima a la CE50, con crecimiento anormal de pelos radicales y radículas delgadas. Los efectos de fitotoxicidad identificados pueden ser atribuibles a la gran acidez del sedimento, alto contenido de aluminio, presencia de metales pesados y de hidrocarburos. Se vincula la necrosis observada en ambos bioensayos con un estrés oxidativo inducido por la deficiencia de calcio y el exceso de cadmio

Historical analysis of rainfall-triggered rockfalls: the case study of the disaster of the ancient hydrothermal Sclafani Spa (Madonie Mts, northern-central Sicily, Italy) in 1851

In 1851, the region of Sicily experienced many rainstorm-induced landslides. On 13 March 1851, a rainstorm brought about a severe rockfall disaster near the small town of Sclafani (Madonie Mountains, northern-central Sicily, Italy). Rocks detached from the carbonate crest of Mt Sclafani (813m above sea level) and fell downslope, causing the collapse of the ancient hydrothermal spa (about 430m above sea level) and burying it. Fortunately, there were no injuries or victims. Given its geological, geomorphological and tectonic features, the calcareous–dolomitic and carbonate–siliciclastic relief of Mt Sclafani is extremely prone to landsliding. This study combines the findings of detailed geological and geomorphological field surveys and of a critical review of documentary data. A thorough analysis of documentary sources and historical maps made it possible to identify the location (previously unknown) of the ancient spa. The rockfall dynamics was reconstructed by comparing field reconnaissance data and documentary sources. The 1851 event reconstruction is an example of the application of an integrated methodological approach, which can yield a propaedeutic, yet meaningful picture of a natural disaster, paving the way for further research (e.g. slope failure susceptibility, future land-use planning, protection of thermal springs and mitigation of the impact of similar disasters in this area). Indeed, the intensification of extreme weather events, caused by global warming induced by climate change, has increased the risk of recurrence of a catastrophic event, like that of the ancient Sclafani spa, which is always a potential threat

The Ictineu 3 project: A modern manned submersible for scientific research and intervention.

This paper describes the current state of Ictineu 3, the first project of Ictineu Submarins S.L., which aims at designing, building and operating a modern manned submersible for scientific research and intervention at a maximum depth of 1200m. This will be the first manned scientific submersible to be built and operated in the Iberian peninsula since the Ictíneo of Narcís Monturiol, and will help reduce the gap in our ocean exploration and intervention capabilities as well as pay a tribute to its old ancestor. This new submersible will employ state of the art technologies in areas such as material engineering, energy storage, navigation, control, and communication systems. Its main applications will range from deep seabed research, science dissemination, environmental protection, and archaeology to salvage operations and support to the offshore industry. The first sea trials are scheduled for the second half of 2010.Peer Reviewe

Historical analysis of rainfall-triggered rockfalls: the case study of the disaster of the ancient hydrothermal Sclafani Spa (Madonie Mts, northern-central Sicily, Italy) in 1851

In 1851, the region of Sicily experienced many rainstorm-induced landslides. On 13 March 1851, a rainstorm brought about a severe rockfall disaster near the small town of Sclafani (Madonie Mountains, northern-central Sicily, Italy). Rocks detached from the carbonate crest of Mt Sclafani (813 m above sea level) and fell downslope, causing the collapse of the ancient hydrothermal spa (about 430 m above sea level) and burying it. Fortunately, there were no injuries or victims. Given its geological, geomorphological and tectonic features, the calcareous–dolomitic and carbonate–siliciclastic relief of Mt Sclafani is extremely prone to landsliding. This study combines the findings of detailed geological and geomorphological field surveys and of a critical review of documentary data. A thorough analysis of documentary sources and historical maps made it possible to identify the location (previously unknown) of the ancient spa. The rockfall dynamics was reconstructed by comparing field reconnaissance data and documentary sources. The 1851 event reconstruction is an example of the application of an integrated methodological approach, which can yield a propaedeutic, yet meaningful picture of a natural disaster, paving the way for further research (e.g. slope failure susceptibility, future land-use planning, protection of thermal springs and mitigation of the impact of similar disasters in this area). Indeed, the intensification of extreme weather events, caused by global warming induced by climate change, has increased the risk of recurrence of a catastrophic event, like that of the ancient Sclafani spa, which is always a potential threat