Variabilidade genética de caracteres relacionados ao enraizamento de estacas de progênies e clones de guanandi (Calophyllum brasiliense Cambess

Pós-graduação em Ciência Florestal - FCA

Variabilidade espacial de atributos do solo e da cultura do milho (Zea mays L.) em dois sistemas de manejo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estimação da densidade de solos utilizando sistemas de inferência fuzzy

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Cultivo do cajueiro anão (Anacardium occidentale L.) nas regionais de Andradina e Jales do estado de São Paulo: tratos culturais, custos e mercados

Pós-graduação em Agronomia - FEIS

Influência da adubação com nitrogênio e fósforo na produção de Jambu, Acmella oleracea (L) R.K. Jansen

The objective of this work was to evaluate the influence of the use of nitrogen and phosphorus in the culture of jambu. The experiment was initiated at the experimental farm of the agency APTA Polo Vale do Ribeira, using the Nazaré cultivar. The experimental design was complete randomized with fourlevelsof nitrogen (0, 37.5, 75 and 112.5 kg ha-1 N) and phosphorus (0, 75, 150 and 300 Kg ha-1P2O5),and four reapplications. After soil preparation, liming and fertilization, seedlings of jambu were transplanted at a spacing of 0.50 x 0.5 m. The experimental plot was 1.0 x 1.0 m. Fresh and dry mass of leaves and flowers and number of flowers were analyzed. The production of fresh and dry leaves and flowers were influenced by fertilization. Thelevelsof nitrogen affected the outcome, as theyprovided a linear increase in all variables, and the phosphorus level of 75 kgha-1 P2O5 caused the highest average production in the number of flowers and in the fresh and dried mass of flowers.

Produção de soja e milho cultivados sobre diferentes coberturas

The no-tillage system is an important technique for maintaining and restoring the productive capacity of conventionally managed soils and degraded areas. The aim of this study was to evaluate the production of soy and maize grown on the straw of five cover crops and on spontaneous vegetation. The experiments were carried out in Votuporanga, in the state of Sao Paulo and in Selviria, in Mato Grosso do Sul, Brazil, in March 2008, after conventional soil preparation. The experimental design was of randomised blocks with four replications, using the following cover crops in different amounts of seed per hectare, to make up the treatments: Sorghum bicolor - 6, 7 and 8 kg ha(-1); Pennisetum americanum - 10, 15 and 20 kg ha(-1); Sorghum sudanense - 12, 15 and 18 kg ha(-1); S. bicolor and S. sudanense hybrid - 8, 9 and 10 kg ha(-1); and Urochloa ruziziensis - 8, 12 and 16 kg ha(-1). A control treatment with spontaneous vegetation was also used. After management of the cover crops, soy was planted in the first year of the study, and maize sown in the second, both under a no-tillage system. The dry matter accumulated by the different cover crops, and the agronomic characteristics of the soy and maize were all evaluated. It was concluded that the different cover plants proved to be good options for preceding the soy crop in Votuporanga, SP and the maize in Selviria, MS, and that the different amounts of seed used for each cover crop resulted in differences in relation to the agronomic characteristics of the crops of soy and maize.

Análise de cenários para auxílio à tomada de decisão no plantio mecanizado de cana-de-açúcar

Pós-graduação em Agronomia (Ciência do Solo) - FCAV

Modelo matemático para determinação do custo e produção de energia na cultura da cana-de-açúcar

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Características agronômicas e demanda energética de cultivares de soja sob efeito dos sistemas de preparo do solo

The aim of this study was to evaluate the influence of preparation: intermediate grade, minimum tillage and no-till on the agronomic characteristics and energy demand of transgenic soybean cultivars and non-GMO soybeans. Soil preparation aims at improving physical, chemical and biological conditions, aiming at good emergence and plant development. The different types of tillage may interfere with the agronomic characteristics and productivity of plants, and in energy use which can cause variation in production costs. Genetically modified plants can be one of the alternatives for reduction of production costs in crops by reducing pesticide applications, enabling higher productivity with less environmental impact. The test was conducted in 2010/2011 at the agricultural Experimental Farm Lageado, belonging to the Faculty of Agronomic Sciences – UNESP, located in the city of Botucatu, SP in an area using no-till systems for the past 12 years. The experiment was carried out in a 3 x 2 factorial, randomized treatments were comprised of three soil preparation systems, minimum cultivation, intermediate grade preparation and no-till, with two cultivars of soybeans: MGBR-46 Conquest (conventional), Valuable RR (Transgenic). The data obtained was submitted to variance analysis using Tukey test at a 5% probability. With the results analyzed it might be observed that there was no significant difference between treatments, in the variables, the percentage of soil cover, final soybean plant population, grain yield and plant height. The results obtained show that the no-till system resulted in higher productivity than conventional tillage and minimum cultivation. The higher specific energy use per area was observed in minimum cultivation with a chisel plough, when compared to the preparation across the grid. The greatest fuel consumption was to treat minimum cultivation with chisel plough. The highest values were found in the skating system of minimum cultivation, being greater in conventional tillage system. It is more satisfactory for the producer to sow transgenic soy using a no-till system, because productivity retrieved from that system compensates for fuel expenditure.

Variabilidade espaço-temporal da emissão de CO2 do solo em curto período sob influência de eventos de precipitação

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

HIV prevalence and contextual risk-factors among injection drug users in Harris County, Texas

Injection drug use is the third most frequent risk factor for new HIV infections in the United States. A dual mode of exposure: unsafe drug using practices and risky sexual behaviors underlies injection drug users' (IDUs) risk for HIV infection. This research study aims to characterize patterns of drug use and sexual behaviors and to examine the social contexts associated with risk behaviors among a sample of injection drug users. ^ This cross-sectional study includes 523 eligible injection drug users from Houston, Texas, recruited into the 2009 National HIV Behavioral Surveillance project. Three separate set of analyses were carried out. First, using latent class analysis (LCA) and maximum likelihood we identified classes of behavior describing levels of HIV risk, from nine drug and sexual behaviors. Second, eight separate multivariable regression models were built to examine the odds of reporting a given risk behavior. We constructed the most parsimonious multivariable model using a manual backward stepwise process. Third, we examined whether HIV serostatus knowledge (self-reported positive, negative, or unknown serostatus) is associated with drug use and sexual HIV risk behaviors. ^ Participants were mostly male, older, and non-Hispanic Black. Forty-two percent of our sample had behaviors putting them at high risk, 25% at moderate risk, and 33% at low risk for HIV infection. Individuals in the High-risk group had the highest probability of risky behaviors, categorized as almost always sharing needles (0.93), seldom using condoms (0.10), reporting recent exchange sex partners (0.90), and practicing anal sex (0.34). We observed that unsafe injecting practices were associated with high risk sexual behaviors. IDUs who shared needles had higher odds of having anal sex (OR=2.89, 95%CI: 1.69-4.92) and unprotected sex (OR=2.66, 95%CI: 1.38-5.10) at last sex. Additionally, homelessness was associated with needle sharing (OR=2.24, 95% CI: 1.34-3.76) and cocaine use was associated with multiple sex partners (OR=1.82, 95% CI: 1.07-3.11). Furthermore, twenty-one percent of the sample was unaware of their HIV serostatus. The three groups were not different from each other in terms of drug-use behaviors: always using a new sterile needle, or in sharing needles or drug preparation equipment. However, IDUs unaware of their HIV serostatus were 33% more likely to report having more than three sexual partners in the past 12 months; 45% more likely to report to have unprotected sex and 85% more likely to use drug and or alcohol during or before at last sex compared to HIV-positive IDUs. ^ This analysis underscores the merit of LCA approach to empirically categorize injection drug users into distinct classes and identify their risk pattern using multiple indicators and our results show considerable overlap of high risk sexual and drug use behaviors among the high-risk class members. The observed clustering pattern of drug and sexual risk behavior among this population confirms that injection drug users do not represent a homogeneous population in terms of HIV risk. These findings will help develop tailored prevention programs.^

La influencia de la deforestación del cerrado brasileño en el cultivo de granos y las consecuencias de la pérdida del suelo en la región de la reserva cachoeira dourada : Brasil central-occidental

El índice de erosividad (EI30) y su espacialización fueron determinados para las cuencas de contribución del sistema hidroeléctrico de la reserva Cachoeira Dourada, localizada entre los Estados de Goias y Minas Gerais, limitada por las coordenadas 640000-760000 m W. y 7910000-7975000 m S. UTM zona 22, Datum Córrego Alegre. Se trataron los datos del promedio mensual y anual de las precipitaciones correspondientes a ocho localidades para un periodo de treinta años. Existe una distribución irregular de precipitación en la región y en consecuencia una espacialización no uniforme de los índices de erosión en el área de influencia de la reserva. Los valores más altos de precipitación coinciden con el periodo de preparación de la tierra para el cultivo y el desarrollo de las plantas de ciclo anual, principalmente soja y maíz.

Optimización de la aplicación de lodos de depuración de aguas residuales al abonado o mejora de suelos

El objetivo de este trabajo de investigación fue evaluar el efecto de la aplicación de lodos residuales procedentes de una planta de tratamiento de aguas residuales acondicionados como biosólido para el abonado de tres cultivos agrícolas. Esto se realizó a través del estudio de las variables de producción (desarrollo vegetal de cada cultivo) y de la comparación de las características de los suelos utilizados antes y después de los ensayos experimentales. A través de la investigación se confirmó la mejora en la calidad del suelo y mejor rendimiento de cultivo debido a los biosólidos procedentes de tratamiento de aguas residuales. Este trabajo de investigación de tipo descriptivo y experimental, utilizó lodos optimizados que fueron aplicados a tres cultivos agrícolas de ciclo corto. Fueron evaluados dos cultivos (sandía y tomate) bajo riego y un cultivo (arroz) en secano. En la primera fase del trabajo se realizó la caracterización de los lodos, para ellos se realizaron pruebas físico químicas y microbiológicas. Fue utilizado el método de determinación de metales por espectrometría de emisión atómica de plasma acoplado inductivamente, (ICP-AES) para conocer las concentraciones de metales. La caracterización microbiológica para coliformes totales y fecales se realizó utilizando la técnica del Número más probable (NMP), y para la identificación de organismos patógenos se utilizó el método microbiológico propuesto por Kornacki & Johnson (2001), que se fundamenta en dos procesos: pruebas presuntivas y prueba confirmativa. Tanto los resultados para la determinación de metales y elementos potencialmente tóxicos; como las pruebas para la determinación de microorganismos potencialmente peligrosos, estuvieron por debajo de los límites considerados peligrosos establecidos por la normativa vigente en Panama (Reglamento Técnico COPANIT 47-2000). Una vez establecido la caracterización de los lodos, se evalúo el potencial de nutrientes (macro y micro) presentes en los biosólidos para su potencial de uso como abono en cultivos agrícolas. El secado de lodos fue realizado a través de una era de secado, donde los lodos fueron deshidratados hasta alcanzar una textura pastosa. “La pasta de lodo” fue transportada al área de los ensayos de campo para continuar el proceso de secado y molida. Tres ensayos experimentales fueron diseñados al azar con cinco tratamientos y cuatro repeticiones para cada uno de los tres cultivos: sandía, tomate, arroz, en parcelas de 10m2 (sandía y tomate) y 20 m2 (arroz) para cada tratamiento. Tres diferentes dosis de biosólidos fueron evaluadas y comparadas con un tratamiento de fertilizante comercial y un tratamiento control. La dosis de fertilizante comercial utilizada en cada cultivo fue la recomendada por el Instituto de Investigación Agropecuaria de Panamá. Los ensayos consideraron la caracterización inicial del suelo, la preparación del suelo, semilla, y arreglo topográfico de los cultivos siguiendo las recomendaciones agronómicas de manejo de cultivo establecida por el Instituto de Investigación Agropecuaria. Para los ensayos de sandía y tomate se instaló el sistema de riego por goteo. Se determinaron los ácidos húmicos presentes en los cultivos, y se estudiaron las variables de desarrollo de cada cultivo (fructificación, cosecha, peso de la cosecha, dimensiones de tamaño y color de las frutas, rendimiento, y la relación costo – rendimiento). También se estudiaron las variaciones de los macro y micro nutrientes y las variaciones de pH, textura de suelo y MO disponible al inicio y al final de cada uno de los ensayos de campo. Todas las variables y covariables fueron analizadas utilizando el programa estadístico INFOSAT (software para análisis estadístico de aplicación general) mediante el análisis de varianza, el método de comparaciones múltiples propuesto por Fisher (LSD Fisher) para comparar las medias de los cultivares y el coeficiente de correlación de Pearson que nos permite analizar si existe una asociación lineal entre dos variables. En la evaluación de los aportes del biosólido a los cultivos se observó que los macronutrientes N y P se encontraban de los límites requeridos en cada uno de los cultivos, pero que los niveles de K estuvieron por debajo de los requerimientos de los cultivos. A nivel de la fertilización tradicional con fertilizante químico se observó que la dosis recomendada para cada uno de los cultivos del estudio estaba sobreestimada en los tres principales macronutrientes: Nitrógeno, Fosforo y Potasio. Contenían concentraciones superiores de N, P y K a las requeridas teóricamente por el cultivo. El nutriente que se aporta en exceso es el Fósforo. Encontramos que para el cultivo de sandía era 18 veces mayor a lo requerido por el cultivo, en tomate fue 12 veces mayor y en el cultivo de arroz, 34 veces mayor. El fertilizante comercial tuvo una influencia en el peso final y rendimiento final en cada uno de los cultivos del estudio. A diferencia, los biosólidos tuvieron una influencia directa en el desarrollo de los cultivos (germinación, coloración, tamaño, longitud, diámetro, floración y resistencia a enfermedades). Para el caso de la sandía la dosis de biosólido más cercana al óptimo para el cultivo es la mayor dosis aplicada en este ensayo (97.2 gramos de biosólido por planta). En el caso de tomate, el fertilizante comercial obtuvo los mejores valores, pero las diferencias son mínimas con relación al tratamiento T1, de menor dosis de biosólido (16.2 gramos de biosólido por planta). Los resultados generales del ensayo de tomate estuvieron por debajo del rendimiento esperado para el cultivo. Los tratamientos de aplicación de biosólidos aportaron al desarrollo del cultivo en las variables tamaño, color y resistencia a las enfermedades dentro del cultivo de tomate. Al igual que el tomate, en el caso del arroz, el tratamiento comercial obtuvo los mejores resultados. Los resultados finales de peso y rendimiento del cultivo indican que el tratamiento (T2), menor dosis de biosólido (32.4 gramos por parcela), no tuvo diferencias significativas con los resultados obtenidos en las parcelas con aplicación de fertilizante comercial (T1). El tratamiento T4 (mayor dosis de biosólido) obtuvo los mejores valores para las variables germinación, ahijamiento y espigamiento del cultivo, pero al momento de la maduración obtuvo los menores resultados. Los biosólidos aportan nutrientes a los cultivos y al final del ensayo se observó que permanecen disponibles en el suelo, aportando a la mejora del suelo final. En los tres ensayos, se pudo comprobar que los aportes de los biosólidos en el desarrollo vegetativo de los cultivos. También se encontró en todos los ensayos que no hubo diferencias significativas (p > 0.05) entre los tratamientos de biosólidos y fertilizante comercial. Para obtener mejores resultados en estos tres ensayos se requeriría que a la composición de biosólidos (utilizada en este ensayo) se le adicione Potasio, Calcio y Magnesio en las cantidades requeridas por cada uno de los cultivos. ABSTRACT The objective of this investigation was to evaluate the effect of residual sewage sludge obtained from the residual water of a treatment plant conditioned as Biosolid used on three reliable agricultural crops. The effect of the added sewage sludge was evaluated through the measurement of production variables such as crop plant development and the comparison of the soil characteristics used before and after the experimental tests. This investigation confirmed that biosolids from wastewater treatment can contribute to the growth of these crops. In this experimental approach, optimized sludge was applied to three short-cycle crops including two low-risk crops (watermelon and tomato) and one high-risk crop (rice) all grown on dry land. In the first phase of work, the characteristics of the sludge were assessed using chemical, physical and microbiological tests. The concentrations of metals were determined by atomic emission spectrometry inductively coupled plasma, (ICP-AES). Microbiological characterization was performed measuring total coliform and fecal count using the most probable number technique (NMP) and microbiological pathogens were identified using Kornacki & Johnson (2001) method based on two processes: presumptive and confirmatory tests. Both the results for the determination of metals and potentially toxic elements, as testing for the determination of potentially dangerous microorganisms were below the limits established by the applicable standard in Panama (Technical Regulate COPANIT 47-2000). After the metal and bacterial characterization of the sludge, the presence of macro or micronutrients in biosolids was measured to evaluate its potential for use as fertilizer in the growth of agricultural crops. The sludge was dehydrated via a drying process into a muddy slurry. The pulp slurry was transported to the field trial area to continue the process of drying and grinding. Three randomized experimental trials were designed to test with five treatment regimens and four replications for each of the crops: watermelon, tomato, rice. The five treatment regimens evaluated were three different doses of bio solid with commercial fertilizer treatment control and no fertilizer treatment control. Treatment areas for the watermelon and tomato were 10m2 plots land and for rice was 20m2. The amount of commercial fertilizer used to treat each crop was based on the amount recommended by Agricultural Research Institute of Panama. The experimental trials considered initial characterization of soil, soil preparation, seed, and crop topographical arrangement following agronomic crop management recommendations. For the tests evaluating the growth of watermelons and tomatoes and drip irrigation system was installed. The amount of humic acids present in the culture were determined and developmental variable of each crop were studied (fruiting crop harvest weight, size dimensions and color of the fruit, performance and cost effectiveness). Changes in macro and micronutrients and changes in pH, soil texture and OM available were measured at the beginning and end of each field trial. All variables and covariates were analyzed using INFOSAT statistical program (software for statistical analysis of general application) by analysis of variance, multiple comparisons method as proposed by Fisher (LSD Fisher) to compare the means of cultivars and the Pearson ratio that allows us to analyze if there is a linear association between two variables. In evaluating the contribution of biosolids to agricultural crops, the study determined that the macronutrients N & P were within the requirements of crops, but K levels were below the requirements of crops. In terms of traditional chemical fertilizer fertilization, we observed that the recommended dose for each study crop was overestimated for the three major nutrients: nitrogen, phosphorus and potassium. Higher concentrations containing N, P and K to the theoretically required by the crop. The recommended dose of commercial fertilizer for crops study contained greater amounts of phosphorus, crops that need. The level of phosphorous was found to be18 times greater than was required for the cultivation of watermelon; 12 times higher than required for tomato, and 34 times higher than required for rice cultivation. Phosphorus inputs of commercial fertilizer were a primary influence on the weight and performance of each crop. Unlike biosolids had a direct influence on crop development (germination, color, size, length, diameter, flowering and disease resistance). In the case of growth of watermelons, the Biosolid dose closest to the optimum for cultivation was applied the highest dose in this assay (97.2 grams of bio solids per plant). In the case of tomatoes, commercial fertilizer had the best values but the differences were minimal when compared to treatment T1, the lower dose of sewage sludge (Biosolid 16.2 grams per plant). The overall results for the tomato crop yield of the trial were lower than expected. Additionally, the application of biosolids treatment contributed to the development of fruit of variable size, color and disease resistance in the tomato crops. Similar to the tomato crop, commercial fertilizer treatment provided the best results for the rice crop. The final results of weight and crop yield for rice indicated that treatment with T2 amount of biosolids (34.2 grams per plot) was not significantly different from the result obtained in the application plot given commercial fertilizer (T1). The T4 (higher dose of bio solid) treatment had the best values for the germination, tillering and bolting variables of the rice crop but for fruit ripening yielded lower results. In all three trials, biosolids demonstrated the ability to contribute in the vegetative growth of crops. It was also found in all test no significant differences (p>0.05) between treatment of bio solid and commercial fertilizer. Biosolids provided nutrients to the crops and even at the end of the trial remained available in the ground soil, contributing to the improvement of the final ground. The best results from these three trials is that the use of bio solids such as those used in this assay would require the addition of potassium, calcium and magnesium in quantities required for each crop.

La regeneración natural del pino silvestre (Pinus sylvestris L.) en el Valle del Lozoya (Madrid): germinación y supervivencia inicial

La fase de establecimiento del regenerado es un proceso crítico para el desarrollo posterior de la masa tanto por las elevadas tasas de mortalidad que habitualmente lleva asociadas, como por proporcionar el material de partida del que van a disponer las fases subsiguientes. Las restricciones a la germinación y establecimiento de la regeneración del pino silvestre varían enormemente entre las distintas regiones de su extensa área de distribución geográfica. La región Mediterránea constituye un hábitat marginal de la especie en el que las condiciones ecológicas son muy diferentes a las del grueso de su área de distribución. Frente a otras limitaciones (frío, luz, encharcamiento…), en el entorno mediterráneo la tasa de mortalidad parece estar asociada a las condiciones micrometeorológicas del período estival - particularmente, a la sequía -, así como a la presencia excesiva de ganado o ungulados silvestres. No obstante, la mayoría de la información disponible sobre el proceso de regeneración de la especie procede del centro y norte de Europa, por lo que no es de aplicación directa en nuestra región, en la que los estudios de este tipo son mucho más escasos. El presente trabajo pretende contribuir a paliar esta relativa escasez a través del estudio del proceso de regeneración natural en el monte “Cabeza de Hierro”, masa irregular por bosquetes de pino silvestre, paradigma de gestión sostenible y uso múltiple. En este entorno, se pretende caracterizar y cuantificar tanto el proceso de germinación y supervivencia de la especie como la influencia de la cobertura vegetal (estratos arbóreo, arbustivo y herbáceo, y capa de restos vegetales) en su desarrollo. Se persigue así mismo analizar el efecto de la compactación del suelo sobre la persistencia de la masa y contrastar y comparar la eficacia de dos tratamientos edáficos de ayuda a la regeneración: escarificado y decapado+acaballonado. Con este fin se han planteado dos diseños experimentales consistentes en sendas redes de muestreo (Red de Muestreo I o RM I y Red de Muestreo II o RM II) integradas, respectivamente, por 192 y 24 parcelas de 1,5x1,5 m ubicadas bajo distintas condiciones de cobertura vegetal. Sobre una parte de estas parcelas (1/4 en la Red de Muestreo I; 1/2 en la Red de Muestreo II) se han aplicado tratamientos de ayuda a la regeneración (RM I: escarificado; RM II: decapado+acaballonado) y, tras llevar a cabo siembras controladas al inicio del período vegetativo, se han practicado controles periódicos de germinación y supervivencia durante uno (RM II) y tres años consecutivos (RM I). Se han realizado así mismo mediciones complementarias de variables micrometeorológicas, espesura, recubrimiento superficial del suelo y compactación. Los resultados obtenidos a partir de las experiencias realizadas en el monte objeto de estudio permiten concluir que, en relación con el proceso de regeneración natural de la especie en este tipo masa y entorno: 1) la regeneración del pino silvestre durante el primer período vegetativo presenta una tasa de éxito muy baja (1,4% de los sembrados), provocada por una elevada mortalidad durante el primer período estival (>92%) subsiguiente a una germinación de en torno al 17% de las semillas viables que llegan al suelo; 2) la mortalidad sigue siendo elevada hasta el tercer período vegetativo, en que comienza a reducirse significativamente hasta alcanzar el 45%; 3) la cobertura vegetal influye significativamente tanto en el proceso de germinación como en el de supervivencia, aunque ambos procesos presentan una baja correlación linear que pone de manifiesto que los lugares idóneos para la germinación no siempre son los más adecuados para la supervivencia; 4) la escarificación del suelo mejora las tasas iniciales de germinación y supervivencia, pero empeora la tasa de supervivencia posterior (años 2 y 3), por lo que su efecto a medio plazo no resulta significativo; 5) el decapado+acaballonado presenta mejores resultados que el escarificado durante el primer verano, aunque sólo resulta efectivo en condiciones intermedias de espesura de masa; 6) la compactación edáfica no resulta limitante para la productividad ni la persistencia de la masa considerada. ABSTRACT Seedling establishment is critical for later stand progress because it involves high mortality rates and the surviving saplings constitute the starting material for all the subsequent stages. Restrictions for Scots pine germination and seedling survival may vary greatly across its geographical range, as it is widely distributed within north latitudes. Mediterranean region is a marginal sector within this species range and its ecological conditions differ greatly from those of the bulk of the area. Mortality rates in Mediterranean environments seem to be related to summer weather (mainly drought) and high livestock stocking rather than to cold, light or flooding. Most available information on scots pine regeneration process comes from north European experiences and is not transferable to Spanish forests, whereas studies on Mediterranean region are much scarcer. The present work aims at broadening Scots pine regeneration knowledge within Mediterranean region by analyzing its establishment process in the “Cabeza de Hierro” forest: a Scots pine uneven-aged forest at blocklevel scale, exemplary managed for multi-services purpose. Germination and surviving processes are to be characterized and quantified as to vegetation cover both in trees, shrubs, grass and litter strata. Soil compaction effects on forest sustainability are also assessed and the efficacy of some site preparation techniques on regeneration success is tested and compared (scarification vs. scalping+mounding). Two sampling networks comprising respectively 198 (SN I) and 24 plots (SN II) of 1.5x1.5m have been established over a wide range of vegetal cover conditions within the forest. Soil preparation techniques have been applied only to some of the sampling points; namely, 1 out of 4 plots have been scarified within Sampling Network I , while 1 out of 2 plots have been object of scalping & mounding within Sampling Network II. After localized sowing prior to growing season, germination and surviving have been periodically sampled for either one (SN II) or three years (SN I). Supplementary measures for micrometeorological variables, stand density, ground vegetal cover and compaction have also been carried out. Results obtained for the studied forest lead to the following insights regarding Scots pine natural regeneration process within this sort of forest and environment: 1) seedling establishment success rate is quite low (0,15% of sowing seeds), due to high mortality during the first summer (>92%), following a prior 17% rate of germination over viable seeds reaching the soil; 2) mortality rate remains high until the third year after emergence and then decreases to the 50% of surviving; 3) although vegetal cover significantly affects both seedling germination and survival, lineal correlation between those two processes is rather low, which may indicate that places fit for emergence are not necessarily suitable for summer surviving; 4) soil scarification improves both germination and survival during the first growing season, but it is associated to higher mortality rates during the next two years; hence it has no significant medium term effect; 5) scalping & mounding treatment is more effective than scarification concerning establishment improving during the first summer; but its effects are only significant under intermediate stand density levels; 6) soil compaction does not restrict either forest productivity or persistence, despite the area’s long history of high livestock stocking rates and mechanized logging.

Acoustic emission and yield in sand

An experimental investigation into the Acoustic Emission (AE) response of sand has been undertaken, and the use of AE as a method of yield point identification has been assessed. Dense, saturated samples of sand were tested in conventional triaxial apparatus. The measurements of stresses and strains were carried out according to current research practice. The AE monitoring system was integrated with the soil mechanics equipment in such a way that sample disturbance was minimised. During monotonically loaded, constant cell pressure tests the total number of events recorded was found to increase at an increasing rate in a manner which may be approximated by a power law. The AE response of the sand was found to be both stress level and stress path dependent. Undrained constant cell pressure tests showed that, unlike drained tests, the AE event rate increased at an increasing rate; this was shown to correlate with the mean effective stress variation. The stress path dependence was most noticeable in extension tests, where the number of events recorded was an order of magnitude less than that recorded in comparable compression tests. This stress path dependence was shown to be due to the differences in the work done by the external stresses. In constant cell pressure tests containing unload/reload cycles it was found that yield could be identified from a discontinuity in the event rate/time curve which occurred during reloading. Further tests involving complex stress paths showed that AE was a useful method of yield point identification. Some tests involving large stress reversals were carried out, and AE identified the inverse yield points more distinctly than conventional methods of yield point identification.