Extracción agrícola de bases en el norte de la provincia de Buenos Aires, Argentina : costo de su remediación e implicancias económicas

El lavado de nutrientes edáficos básicos, su extracción agropecuaria, la fertilización y la deposición de compuestos de N, S e H presentes en la atmósfera, entre otros, causan acidificación edáfica. La escasez y el desbalance nutricional ocasionado limita la producción vegetal. Este fenómeno se advirtió recientemente en la Región Pampeana Argentina, donde la reposición de Ca2+, Mg2+ y K+ ha sido limitada en el pasado. El objetivo del trabajo fue evaluar la extracción de bases causada por la agricultura en el norte de la provincia de Buenos Aires (1.684.753 ha) durante el período 1970-2003, cuantificar económicamente su remediación y analizar sus implicancias económicas. La extracción de K+, Ca2+ y Mg2+ fue estimada en 682.692, 88.443 y 155.479 Mg totales para la región, respectivamente, en el período considerado. El costo de la reposición para suelos cultivados con soja, maíz, trigo y girasol es de 414.000.000; 127.300.000; 86.200.000 y 16.000.000, representando 6,6%, 3,4%, 4,0% y 2,9% del ingreso debido a su producción. El análisis socioeconómico regional señala condiciones actuales de agravamiento de los factores predisponentes a la problemática edáfica, la potencialidad de perjuicios económicos para la región y el país, y marca la necesidad de estrategias de gestión que favorezcan la reposición de estos elementos.The leaching of basic edaphic nutrients, its farming extraction, fertilization and the N, S and H compounds deposition from the atmosphere, among others, cause edaphic acidification. The shortage and provoked nutritional unbalance limit the vegetal production. This phenomenon has recently been noticed in the Pampeana Region of Argentina, where the replacement of Ca2+, Mg2+ and K+ was limited in the past. The objective of this work has been to evaluate the extraction of bases caused by agriculture in the north of the province of Buenos Aires (1,684,753 ha) within the mentioned region (1970-2003), to quantify economically its remediation and to analyze its socioeconomic implications.Principio del formulario The extraction of K+, Ca2+ and Mg2+ has been estimated in 682,692; 88,443 and 155,479 Mg for the total region, respectively, and the considered period. Replacement costs are 414.000.000; 127.300.000; 86.200.000 and 16.000.000 for fields cultivated with soybean, maize, sunflower and wheat, representing 6.6%, 3.4%, 4.0% y 2.9% of the income derived from its production. The regional socioeconomic analysis indicates present conditions worsening of the predisposing factors to the edaphic problematic situation, the potentiality of economic damages for the region and the country, and it marks the necessity of management strategies that favor the replacement of these elements

The intergenic spacer region of the rDNA in Haplopappus gracilis (Nutt.) Gray

In this paper we provide further information on the genome organization of Haplopappus gracilis, one of the six angiosperms showing the lowest chromosome number, i.e. 2n=4, by determining the nucleotide sequence of the Intergenic Spacer region of the rRNA genes and its cytological localization on metaphase chromosomes. DNA sequence analysis reveals the occurring of a product of 4,382 bp in length, characterized by the presence of four blocks of different repeated sequences. Our analysis also evidenced putative promoter regions with three Transcription Initiation Sites for Polymerase I, as previously reported in Artemisia absinthium, belonging to the same Asteraceae family. A fluorescent in situ hybridization with the Intergenic Spacer probe indicates the presence of rDNA genes only in the satellited chromosomes of H. gracilis; besides differences in the signal intensity between homologous chromosomes were frequently observed, so suggesting, for these chromosome sites, the presence of a variable number of rDNA gene copies, even if a divergent chromatin organization in corresponding regions can not be ruled out

Characterization of normal and "albino" phenotypes in Erythrina crista-galli

We present here a characterization of Erythrina crista-galli L. (syn: Erythrina lamifolia Jacq.) seedlings, obtained from a plant from the Botanical Garden of Pisa University. This plant produces seeds that, during germination, have shown two different seedling phenotypes: normal (NT, 75%) and "albino" types (AT, 25%). Albino seedlings survive only 8–9 weeks and their growth is dramatically reduced when compared with wild type seedlings. Biochemical investigations have shown that albino seedlings completely lack chlorophyll and carotenoids and also soluble sugar levels are lower than in the normal type. We have also conducted sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) experiments and silver staining analysis on different protein extracts from shoots and leaves of both phenotypes, and demonstrated strong differences in protein patterns. The almost total absence of putative small and large RuBisCo bands in albino seedlings should be emphasized. We have also microspectrophotometrica..

Influence of the organic matter on the specific surface of a Typic argiudoll

El contenido de materia orgánica (MO) del suelo se relaciona positivamente, en algunos casos, con la superficie específica (SE) del mismo, pero grandes cantidades de MO pueden resultar en una SE menor, cuando se la determina a través de la adsorción de nitrógeno a bajas temperaturas. Tradicionalmente se asocia a la MO una elevada SE, del orden de los 500 a 800 m2 g-1. Estos valores, obtenidos mediante técnicas que emplean solventes polares, por ejemplo, etilenglicol, hicieron suponer que la misma contribuye en gran medida a la SE del suelo. No obstante, hay referencias que señalan una sobrestimación de los resultados obtenidos, atribuida a la utilización de estos solventes. Mediciones que emplean el método con adsorción de N2 a 77 K, cuya interpretación se basa en el modelo de Brunauer, Emmett y Teller (BET), considerado internacionalmente como método patrón, arrojan valores de SE para la MO que son menores que los primeros, en dos órdenes de magnitud. Con el objetivo de aportar conocimiento que contribuyera a una mejor comprensión del papel de la MO en procesos edáficos, se realizaron determinaciones de SE en muestras de un Argiudol típico, con diferentes contenidos de MO y contenido de arcilla constante (20%). Las medidas se llevaron a cabo interpretando las isotermas de adsorción de N2 a 77 K, mediante el modelo BET. Los resultados obtenidos mostraron una relación no lineal negativa entre la SE y el contenido de MO. La eliminación de la MO mediante H2O2 incrementó la SE de las muestras en todos los casos. La variación de SE por unidad de MO eliminada sugiere que la misma no se adsorbe de manera uniforme y continua sobre la superficie de la fase mineral.The organic matter (OM) of soil is positively related to the specific surface area (SSA), but large amounts of OM result in reduced SSA when determined by the Brunauer-Emmett- Teller (BET) method with N2 adsorption at low temperature. It is common to assign a large SSA to OM, ranging from 500 to 800 m2 g-1. These values, obtained with methods using polar adsorbates, e.g. ethylene glycol, imply a high contribution of OM to soil SSA. However, some works claimed an overestimation of the effect of OM on SSA when polar solvents are used. Measurements with the BET method (using N2 at 77 K), considered internationally as a standard method, resulted in values of SSA for OM two order of magnitude smaller than the former ones. With the objective to contribute to a better knowledge about the OM role in edaphological processes, determinations of SSA in samples from a Typic argiudoll with different OM contents were made. Measurements of SSA were carried out with N2 at 77 K, and the isotherms were interpreted with the BET model. Results showed a negative non linear relationship between SSA and the OM content of the samples. Destruction of OM with H2O2 increased SSA in all cases. The increments in SSA, normalized by the content of removed OM, suggested that the adsorption of OM on the mineral surface is not uniform.Fil: Gelati, Pablo R..Fil: Sarli, Guillermo O..Fil: Soracco, Carlos Germán.Fil: Lozano, Luis A..Fil: Filgueira, Roberto R.

RESULTS OF STUDIES ON THE MESO-CENOZOIC SUCCESSION IN THE MONTE OLIMPINO 2 TUNNEL. THE TECTONO-SEDIMENTARY SIGNIFICANCE OF THE "GONFOLITE LOMBARDA"

The construction of the Monte Olimpino 2 railway tunnel connecting Chiasso (Switzerland) and Bernate (to the South of Como, Italy) allowed the continuous observation of the poorly outcropping Mesozoic to Cenozoic succession and the collection of new stratigraphic and structural data which are significant for the reconstruction of the South-alpine margin evolution. The Mesozoic succession (lower Jurassic to lower Cretaceous) is strongly tectonized and thinned. The Selcifero Lombardo is represented by a sliver of radiolarites; the Maiolica is only 15 m thick and the Scaglia Variegata reaches a maximum local thickness of 1.5 m of cataclastic marls. From a stratigraphic point of view the presence of lithofacies referable to the lower lithozone of the Sogno Formation (upper Lias) is noteworthy. They occurr at the same stratigraphic position of the nearly outcropping Rosso Ammonitico Lombardo (Breggia river, Switzerland) and are indicative of relatively deeper sedimentation within the Generoso Basin. The overlying Oligocene to middle Miocene deep marine clastic succession, the "Gonfolíte Lombarda", is separated from the Mesozoic succession by a North-vergent thrust. Four depositional sequences have been recognized on the basis of major unconformities and of the progradation-retrogradation pattern of the depositional system. A gradual increase of the tectonic tilt from the bottom to the top ("progressive unconformity"), recurrent cannibalization phenomena and lateral shifting of the clastic buildups characterize the whole succession

Synsedimentary tectonics and sedimentation in the Tertiary Piedmont Basin, Northwestern Italy

The Late Oligocene/Early Miocene tectonic and sedimentary evolution of the eastern sector of the Langhe Sub-Basin (Tertiary Piedmont Basin) is proposed and discussed. The area is located between the villages of Roccaverano and Mombaldone, along the western side of the Bormida di Spigno River Valley (see attached geologic map). Synsedimentary tectonics strongly influenced the geologic evolution of the region during the time span examined, being particularly evident at three specific "times" that were chosen as models. During "Time 1" (Late Oligocene) gentle anticlines, aligned WNW-ESE and NW-SE, started to form, affecting only hemipelagic mudstones and creating structural highs that controlled the areal distribution of both turbidites (i.e. T. Ovrano High) and a thick pelitic slump sheet (i.e. M. Pisone High). During "Time 2" (Aquitanian) the C. Mazzurini Half-Graben developed, separated by W-E and WNW-ESE growth faults from the M. Ovrano High to the north and gradually connecting, through a gently sloping ramp, with the Rocchetta High to the south. Turbidity currents and debris flows were channeled into the half-graben, while hemipelagic limestones were deposited onto the adjacent higher areas. During "Time 3" (Early Burdigalian) the depocenter of the depression shifted southward, while the half-graben evolved into a wide trough (Piantivello Trough) characterized by turbidites. Subsequently, the strongly irregular topography was progressively leveled to the quite homogeneous landscape on which the Cortemilia Formation (Late Burdigalian) was deposited

Single stage reconstruction of complex head and neck defects involving the skin with a single ALT flap: A ten year review

Background: Multicomponent defects of the head and neck involving the cervical skin pose a reconstructive challenge for microsurgeons and usually requires two flaps. However, many patients who undergo such surgical treatment had prior treatment with radiotherapy and the availability of recipient vessels for free flap reconstruction may be limited. The purpose of this study was to review our experience in the reconstruction of these extensive head and neck defects using a single ALT free flap. Methods: A total of 21 patients with complex defects of the head and neck involving multiple anatomical subunits, including the overlying cervical skin, underwent reconstruction with a single ALT flap. The clinical, functional, and aesthetic outcomes of these patients were reviewed. Results: The mean hospital stay was 24 days. There was one total flap loss due to pedicle thrombosis. The patient underwent a further ALT reconstruction with no postoperative complications. Cervical fistulas occurred in three patients, and all fistulas were healed by simple wound packing. Three patients with tracheal defect had a functional tracheostoma with adequate stomal patency. A modified barium swallowing study was performed on each patient, and all of them achieved total oral intake. Among them, two patients tolerated only a pureed diet. Conclusions: Complex neck reconstruction can be accomplished with a single ALT flap with good clinical and functional results, minimal morbidity and quick recovery

Control of the urban pigeon Columba livia population and the preservation of common swift Apus apus and bats Chiroptera during the restoration of the Ghirlandina tower in the city of Modena (Italy)

Ferri, M., Ferraresi, M., Gelati, A., Zannetti, G., Domenichini, A., Ravizza, L., Cadignani, R

An integrated assessment framework for the analysis of multiple pressures in aquatic ecosystems and the appraisal of management options

The contribution illustrates an integrated assessment framework aimed at evaluating the relationships between multiple pressures and water body status for the purposes of river basin management. The framework includes the following steps. (1) Understanding how the different pressures affect the status of water bodies. This entails the characterization of biophysical state variables and the definition of a causal relationship between pressures and status. Therefore this step involves interaction between experts bearing ecological understanding and experts providing models to represent the effect of pressures. (2) Identifying the relevant pressures to be addressed through appropriate measures to improve the status of water bodies. (3) Evaluating reduction targets for the relevant pressures identified in a river basin, by weighting the effort associated to reducing individual pressures and the potential benefits in terms of water body status. (4) Designing management measures through a creative process and political discussion of alternative options, balancing costs, benefits and effectiveness based on engineering and economic analysis. (5) Simulating scenarios of implementation of a programme of measures in order to check their effectiveness and robustness against climate and land use change. We discuss the five steps of the assessment framework, and particularly the interaction between science and policy at the different stages. We review the assessment tools required at each step and, for setting optimal pressure reduction targets (step 3), we propose and illustrate a simplified multicriteria approach based on semi-quantitative assessment, which produces frontiers of optimal trade-offs between effort spent on measures, and achievements

Effects of supplementary irrigation on the salinity and sodicity of soils

El aumento poblacional en los próximos 25 años demandará un incremento de producción de alimentos, el que ocurrirá principalmente a partir del aumento de superficie arable y ella a través del riego, de evitarse el deterioro del suelo relacionado con esta práctica. Recientemente en la Pradera Pampeana, el riego complementario se difundió ampliamente. Se plantea que el mismo causa un deterioro edáfico, propio del agroecosistema y del agua usada, condicionando el empleo de sistemas clasificatorios del agua no calibrados regionalmente y que utilizan umbrales de peligrosidad considerablemente distintos. El objetivo de este trabajo fue evaluar la sustentabilidad del riego mediante la evolución de la solución edáfica en NO/Centro-E de la provincia de Buenos Aires, así como la aplicabilidad de criterios clasificatorios del agua. Los suelos estudiados fueron Hapludol Éntico/Típico (NO) y Udipsament Típico (Centro- E). Antigüedad del riego: 2-4 años (90 -150 mm/año). Se analizó suelo en situaciones: Testigo/Riego (fuera y dentro del pivote de riego), 0-20/20-40/40-60 cm de profundidad (muestreo compuesto), años 97 al 99, y agua de riego. Las aguas del Centro-E fueron desde no salinas a mediana/altamente salinas (CE:0,6-0,8 dS m-1) y desde no sódicas a predisponentes a problemas de infiltración (RAS:0,9-6,6), las del NO desde no salinas hasta altamente salinas (CE:0,7-1,3 dS m-1) y desde no sódicas hasta sódicas (RAS:7,2-9,6), predominando el NaCO3H. La relación Mg2+/Ca2+ (0,29-1,57) alcanzaría valores peligrosos por su incidencia en la sodificación. Se comprobaron aumentos de salinidad/sodicidad variables de acuerdo a cada situación, demostrando que la no sustentabilidad de la práctica depende de las características propias de cada agroecosistema. Estos procesos no fueron previsibles mediante las clasificaciones de la aptitud del agua utilizadas, evidenciando la necesidad de desarrollar criterios calibrados regionalmente.The estimated growth of the world population in the next 25 years predicts that the world food supply will have to increase considerably, most probably as a result of increasing the cultivated area by irrigating marginal areas, provided that this practice does not deteriorate soil quality. Recently, supplementary irrigation has been widely adopted by farmers of the Pampean Prairie, which may lead to soil deterioration, due to the nature of the ecosystem and the use of uncalibrated water in the region, which employ considerably differents dangerous threshold. The purpose of this work was to evaluate the sustainability of irrigated production systems by analyzing the evolution of the edaphic solution at North-West/Mid-East sites in the Province of Buenos Aires. Additionally, the possible use of water classification criteria was assessed. The soils of the experimental area were Typic/Entic Hapludol and Typic Udipsament. Irrigation was performed for a period between 2-4 years (90 - 150 mm/yr). Control (unirrigated) and irrigated soils (within and outside an irrigation pivot) were analyzed at depths of 0-20, 20-40 and 40-60 cm , from 1997 to 1999. Waters of the ME location ranged from non saline to highly saline (EC: 0.6-0.8 dSm m-1) and from low to high Na, which might lead to infiltration problems (SAR: 0,9-6,6). Water of the NW area ranged from non saline to highly saline (EC: 0,7-1,3 dS m-1) and the sodium content ranged between non-sodic to sodic water (SAR:7,2-9,6). The Mg/Ca (0,29-1,57) relationship may reach high levels, which is dangerous considering its effect upon sodification. Increases in salt and sodium soil content were variable in each situation, suggesting that the sustainability of irrigation depends upon the characteristics of the agroecosystem. It was not possible to predict the effect of irrigation based on the classification of irrigation water used, suggesting that a water classification system based on local criteria is needed.Facultad de Ciencias Agrarias y Forestale