153 research outputs found

    Gestión de la fertilidad de suelos y la nutrición de plantaciones de teca (Tectona grandis L.f.) en América Central

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    La teca (Tectona grandis L.f.) ha sido tradicionalmente considerada como una madera preciosa en los países del SE Asiático, de donde es originaria, pero durante las últimas décadas ha alcanzado especial relevancia en el sector internacional de las maderas tropicales duras de buena calidad. La especie ha sido ampliamente establecida en América Central, donde tiene una gran importancia socioeconómica, tanto por el impacto de las grandes empresas multinacionales que gestionan grandes plantaciones en la región, como por el gran número de pequeños y medianos propietarios que han elegido esta especie para reforestar sus tierras. Pese a la gran importancia de esta especie, se ha desarrollado relativamente poca investigación acerca de su nutrición y de la gestión del suelo necesaria para su establecimiento y mantenimiento en condiciones sostenibles y productivas. En la presente Tesis Doctoral, tras realizar una amplia revisión bibliográfica, se caracterizan los suelos y la nutrición de las plantaciones de teca en América Central y se proponen varias herramientas para la mejora de su gestión. Las plantaciones de teca de América Central presentan habitualmente deficiencias de K y P, además de algunos problemas de acidez ocasionales. Estos se originan, principalmente, por la mala selección de sitio que se realizó en las últimas dos décadas del siglo XX y por el establecimiento de plantaciones de teca por pequeños propietarios en terrenos que no tienen características propicias para la especie. Además, estos problemas comunes relativos a la baja disponibilidad de P y de K en el suelo son causantes de las relativamente bajas concentraciones foliares de estos elementos (0,88±0,07% K y 0,16±0,04% P) encontradas en plantaciones de teca características de la región. Se presentan varios modelos estadísticos que permiten a los gestores: (a) usarlos como referencia para la interpretación de análisis foliares, ya que ofrecen valores que se consideran característicos de plantaciones de teca con un buen estado nutricional; (b) estimar la cantidad de nutrientes acumulados en la biomasa aérea de sus plantaciones y, sobre todo, su extracción a través de la madera en un aprovechamiento forestal, bien sea una clara o la corta final. La gran acumulación de N, P y K en plantaciones de teca ha de ser considerada como un factor fundamental en su gestión. Además, P y K adquieren mayor relevancia aún ya que su extracción del sistema a través de la madera y su escasa disponibilidad en los suelos hacen que se presente un importante desequilibrio que pone en riesgo la sostenibilidad del sistema. En ese sentido, cambiar la época de cosecha, de la actual (en Enero-Mayo) a Septiembre o Diciembre, puede reducir entre un 24 y un 28% la salida de N asociada a la extracción de madera, un 29% la de P y entre un 14 y un 43% la de K. Se estima que la concentración foliar de P es un factor limitante de la productividad de plantaciones de teca en América Central, proponiéndose un nivel crítico de 0,125%. Además, la teca presenta una tolerancia muy baja a suelos salinos, tendencia que no había sido señalada hasta el momento, siendo muy alta la probabilidad de que la plantación tenga un crecimiento lento o muy lento cuando la Saturación de Na es mayor de 1,1%. Por otro lado, se confirma que K es uno de los elementos clave en la nutrición de las plantaciones de teca en la región centroamericana, proponiéndose un nivel crítico provisional de 3,09% para la Saturación de K, por encima del cual es muy probable que la plantación tenga un crecimiento muy alto. Se ha comprobado que las técnicas estadísticas de análisis multivariante pueden ser usadas como herramientas para agrupar los rodales en base a sus similitudes en cuanto a la fertilidad del suelo y mejorar así el diseño de planes de fertilización en plantaciones con una superficie relativamente grande. De esta manera, se pueden ajustar planes de fertilización más eficientes a escala de grupos de rodales, como un primer paso hacia la selvicultura de precisión, intensificando y diversificando la gestión en función de las diferencias edáficas. Finalmente, aunque los análisis foliares y de suelos indiquen la existencia de deficiencias nutricionales, la fertilización de las plantaciones no siempre va a producir efectos positivos sobre su crecimiento si no se diseña adecuadamente teniendo en cuenta varios factores que pueden estar influyendo negativamente en dicha respuesta, como la densidad de las plantaciones (sinergias con la programación de los clareos y claras) y la elección de la dosis y del producto a aplicar (habitualmente dosis bajas de N-P-K en lugar de incluir otros nutrientes como Mg, B y Zn o usar otros productos como micorrizas, biofertilizantes etc…). ABSTRACT Teak (Tectona grandis L.f.) has been traditionally considered as a precious wood in SE Asia, where it is indigenous. However, during recent decades the species has reached worldwide relevance in the tropical high quality hardwood sector. Teak has been widely established in Central America, where it has become a key species in the forest sector due to its socioeconomic impact, either because of the big-scale plantations of transnational companies and the abundant small-scale plantations established by many farmers. Despite the relevance of the species, little research has been carried out regarding its soil fertility and nutrition management, a key issue both for sustainability and productivity. The present Thesis performs a literature review to this respect, characterize the soil fertility and the nutrition of teak plantations of Central America and propose several management tools. Soil deficiencies of K and P are usually found in teak plantations in Central America, in addition to occasional acidity problems. These problems are mainly derived of (a) a poor site selection performed during 80s and 90s; and (b) small-scale plantations by farmers in sites which are not adequate for the species. These common soil fertility problems related with P and K soil availability are probably the cause of the relatively low P and K foliar concentration (0,88±0,07% K y 0,16±0,04% P) found in representative teak plantations of the region. Several statistical models are proposed, which allow forest managers to: (a) use them as a reference for foliar analysis interpretation, as they show values considered as representative for teak plantations with an adequate nutritional status in the region; (b) estimate the amount of nutrients accumulated in the aerial biomass of the plantations and, especially, the amount of them which are extracted from the systems as wood is harvested in thinning or final clearcuts. The accumulation of N, P and K result in a key factor for teak management in the region. This turns out to be especially relevant for the P and K because their high output rate by timber extraction and the low soil availability result in an important unbalance which constitutes a risk regarding the sustainability of the system. To this respect, modifying the harvesting time from the usual right now (January-May, business as usual scenario) to September or December (proposed alternatives) can reduce between 24 and 28% the N output associated to timber extraction, 29% the P output and between 14 and 43% the K. Foliar P concentration is a main limiting factor for teak plantations productivity in Central America and a 0.125% critical level is proposed. In addition, the results show a very low tolerance for soil salinity, tendency which was not previously reported. Hence, the probability of teak plantations to have low or very low Site Index is high when Na Saturation is higher than 1.1%. On the other hand, K is confirmed as one of the key nutrients regarding teak nutrition in Central America and a 3.09% provisional critical level is proposed for K Saturation; when values are above this level the probability of having very high Site Index is high. Multivariate statistical analyses have been successfully tested to be used as tools to group forest stands according to their soil fertility similarities. Hence, more efficient fertilization plans can be designed for each group of stands, intensifying and diversifying nutritional management according to soil fertility differences. This methodology, which is considered as a first step towards precision forestry, is regarded as helpful tool to design fertilization plans in big scale plantations. Finally, even though foliar and soil analysis would point out some nutritional deficiencies in a forest stand, the results show how the fertilization is not always going to have a positive effect over forest growth if it is not adequately designed. Some factors have been identified as determinants of tree response to fertilization: density (synergisms between fertilization and thinning scheduling) and the appropriate selection of dosages and product (usually low dosages are applied and N-P-K is preferred instead of applying other nutrients such as Mg, B or Zn or using other alternatives such as mycorrhizas or biofertilizers)

    Microclimate accounts for demographic, morphological and reproductive differentiation of two neighbour peripheral populations of the canopy-forming Fucus guiryi

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    Demography, reproductive ecology and thermal regime of Fucus guiryi from the Strait of Gibraltar was monitored between 2018-2019, at two populations ca. 7 km apart (Tarifa and Guadalmesí, South Spain). Due to its peripheral and southern range distribution, they are characterized by low population density and minimum length of reproductive individuals, shorter individuals, and higher individual bushiness in comparison to their northern counterparts. Significant interactions were detected among populations and sampling locations and related to local environmental conditions. Tarifa population had higher population density, cover, extent, and more aggregated individuals, while Guadalmesí had a patchier distribution. Outside the canopies of F. guiryi in Tarifa there is a plethora of biota growing on the numerous protruding rocks, leading to varying microhabitats, while at Guadalmesí, there is only barnacle-covered bare rock. Accordingly, specimens from Tarifa had greater mean and maximum individual lengths, a higher minimum length of reproductive individuals, a greater proportion of mature receptacles and higher individual bushiness. Thermal regime and wave exposure confirmed that F. guiryi from Guadalmesí is exposed to higher disruptive stress due to higher summer temperatures, which is less buffered due to its distribution. Between summer and fall 2018, high summer air temperatures, exceeding overall mean historical records, caused the breakage of apical fronds at Guadalmesí, disrupting the expected parallel seasonal dynamics. Thallus height declined towards the upper intertidal limits to a similar extent in both populations. Canopies of F. guiryi ameliorated understory microclimatic conditions, by reducing the temperature in 5-7ºC and surface irradiance by 10-16%. Demographic, morphological and reproduction-related variables from these populations consistently “fit in” the core to edge trends reported along Portuguese Iberian coasts.Ministerio de Economía y Competitividad Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Assessment of Apps Aimed at Developing Basic Instrumental Skills in Autistic Children and Teenagers

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    It is crucial for families and professionals to promote basic instrumental skills in children with autism, as these skills can help with comprehensive growth and development, and are a starting point in acquiring the essential tools needed for one to live an independent and successful life, These skills include oral language, reading, writing, and mathematics. Therefore, given that ICT and mobile applications (apps) are effective tools that offer suitable content, and are designed exclusively for people with this disorder, working on these skills with apps is an interesting option that is worthy of our attention. We analyzed 88 apps that focused on these skills, through a duly validated system of indicators, calculating frequencies, percentages, measures of central tendency and dispersion, and non-parametric contrast statistics. The app search was carried out in the Google Play Store, with the keyword “autism”, in English and in Spanish. Most of the apps focused on aspects linked to oral language and reading, but few were aimed at reading and mathematics. In addition to the apps’ lack of specialization in the last two skills, the vast majority did not specify the age group for which their content was intended.University of Granada and Spanish Ministry of Education, Innovation, and Universities (aid for university teacher training (FPU19/00026)

    How can seasonality modulate thermal sensitivity in early stages of fucoids?: The colder, the better

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    In the face of ocean global change, determining critical thermal thresholds for marine organisms is a key aspect to predict the survival and persistence of populations, particularly those from rear-edge areas. Seasonal variability implies acclimation of adult individuals, which might result in shifting thermal sensitivities of their recruits. In this work, we aimed to investigate the influence of natural seasonal parental acclimation on the warming response of single- and few-celled stages of Fucus guiryi, a monoecious fucoid from the east Atlantic coast and Strait of Gibraltar, whose populations are iteroparous. To address this, we obtained embryos from fertile thalli collected in early summer, late summer, and winter. In the three replicate experiments under laboratory-controlled conditions, we followed growth, development, survival, and photosynthetic responses of embryos exposed to control (15ºC) and warming conditions (25ºC) for 3 weeks, and initial elemental composition was characterized. Our findings revealed that breeding from winter parents possessed broader thermal sensitivity and thrived better under warming conditions than those from summer specimens, where only 50% survived and experience 75% reductions in photosynthetic rates. Nevertheless, there was a significant gain in thermal resilience from early to late summer regarding survival at 25º C. This research highlighted that warmer winters would not potentially harm new recruits, while extreme temperature events in early summer might compromise the survival of the most sensitive early summer recruits, considering the RCP8.5 predictions for 2050. The influence of parental and provisioning effects and how this might be applied to ecological restoration is discussed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    DIE HAUTTEMPERATUR WEIST BEI MORALISCHEN DILEMMATA AUF EMPATHIE HIN: EINE EXPERIMENTELLE STUDIE MIT INFRAROT -THERMOGRAPHIE

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    [EN]The main objective of this research is to investigate the relationship between skin temperature changes, empathy and moral behaviour through the application of thermography. We recorded the skin temperature changes that occur during the presentation of one personal and one impersonal moral dilemma to high and low-empathy participants. The time needed to make this moral judgement was used as an indicator of the cognitive style of the participant: intuitive thinking (emotional) or deliberate thinking (utilitarian or logical). The main results were as follows: Large temperature changes oc- curred in high-empathy participants (overall in the personal dilemma) that could be understood as a skin representation of emotional judgements. These participants also tended to make non-utilitarian judgements. On the other hand, the low-empathy participants tended to make utilitarian judgements, and this study found that their change in skin tempera- ture was almost always non-significant. The findings are discussed on an emotion-based description of moral dilemmas. [DE]Hauptziel dieser Forschung ist es, den Zusammenhang zwischen den Temperaturschwankungen der Haut, Empathie und moralisches Verhalten mittels Thermografie zu untersuchen. Es wurden die Veränderungen der Hauttemperatur aufgezeichnet, die bei der Präsentation eines persönlichen und eines unpersönlichen moralischen Dilemmas bei Teilnehmern mit hohen und niedrigen Einfühlungsvermögen auftreten. Die Zeit, die für dieses moralische Urteil benötigt wurde, wurde als Indikator für den kognitiven Stil des Teilnehmers verstanden: Intuitives (emotionales) oder bewusstes Denken (utilitaristisch oder logisch). Die wichtigsten Ergebnisse waren: Große Temperatur- Veränderungen wurden bei hochempathischen Teilnehmern beobachtet, besonders im persönlichen Dilemma). Das könnte als die Repräsentation emotionaler Urteile an der Haut verstanden werden. Diese Teilnehmer neigten auch dazu, nicht utilitaristische Urteile zu fällen. Auf der anderen Seite tendierten die gering-empathischen Teilnehmer dazu, utilitaristische Urteile zu fällen, und die Studie ergab, dass ihre Hauttemperaturveränderung fast immer unbedeutend war. Die Ergebnisse werden auf einer emotionsbasierten Beschreibung moralischer Dilemmata diskutiert

    Development of a smart tool to manage family purchases

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    Trabajo de Fin de Grado en Ingeniería Informática, Facultad de Informática UCM, Departamento de Sistemas Informáticos y Computación, Curso 2021/2022.El presente trabajo consiste en una aplicación Android para la gestión de las listas de la compra en los hogares. Esta aplicación se ha diseñado de modo que las funcionalidades implementadas resulten sencillas, cómodas e intuitivas de usar para el usuario. Para fomentar la interacción de los usuarios se ha desarrollado un sistema que permite compartir listas entre usuarios de la aplicación de modo que puedan acceder a listas de otros usuarios. Además, los usuarios tendrán un historial de listas para poder ver las últimas compras realizadas y obtener estadísticas detalladas de ellas.This work consists of an Android application for the management of household shopping lists. This application has been designed in such a way that the implemented functionalities are simple, comfortable and intuitive to use for the user. To encourage user interaction, a system has been developed that allows sharing lists between users of the application so that they can access other users' lists. Inaddition,users will have a list history so that they can see the last purchases made and obtain detailed statistics on them.Depto. de Sistemas Informáticos y ComputaciónFac. de InformáticaTRUEunpu

    Resilience of a warm-temperate fucoid to a simulated marine heatwave: Exploring the interplay between life stages and tissues in relation to emersion.

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    Oral communication presented at Symposia 8 "Algal photosynthesis, carbon fixation and respiration"Marine heatwaves (MHW) represent one of the main climatic threats for seaweed assemblages, altering their functioning, structure, and ecosystem services. Experimental simulations allow to assess the potential impacts of MHWs, given the unpredictability of these events and frequently, the lack of responsive workflows to access the target population during these events. This study explored the ability of the warm-temperate intertidal fucoid Fucus guiryi to respond to a simulated MHW. We aimed to evaluate the intraspecific response of different life stages (adult/juvenile/recruit) and blade types (vegetative / fertile−receptacles) in response to emersion, and to ascertain whether previous moderate MHWs in the area might impact its recruitment. The experimental design accounted for daily thermal and emersion fluctuations considering the most intense registered MHW event and maximum air temperatures in the study area. Photophysiological evaluation revealed that receptacles were the most resilient tissue to the combined effects of heat and emersion, followed by canopy-protected embryos. Vegetative apices and plantlets exhibited marked declines in Fv/Fm, ETRmax and NPQmax close to the MHW peak, due to the additive stressors, while embryos were more affected by the end of the experiment. During the recovery and end phases, recruit density dropped by 50% in the MHW treatment, being 80% of extruded structures unfertilized egg packets, while in the control treatment recruitment was successful and up to 35-times higher. Fucus guiryi was able to recover from the MHW, but more intense and frequent events might affect their reproductive output and compromise its long-term survival.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Temporal and spatial variability in population traits of an intertidal fucoid reveals local-scale climatic refugia

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    Global change is imposing significant losses in the functional traits of marine organisms. Although areas of climatic refugia ameliorate local conditions and help them to persist, the extent to which mesoscale effects contribute for intraregional variability on population traits and conservation is uncertain. Here we assess patterns of conservation status of Fucus guiryi, the main intertidal habitat-forming seaweed in the Strait of Gibraltar (southern Spain and northern Morocco). We investigated the demography, reproductive phenology, and morphology at northern and southern side populations. Population traits were compared seasonally within populations from each side, and at spatial scale in early summer 2019. In the last decade three populations became extinct; two marginal populations had dispersed individuals with a narrower fertility season and miniaturized individuals below 3 cm; and five populations showed variable density and cover with more than 20% of reproductive individuals over the seasons. Highest density, cover, morphology, and reproductive potential was detected at one population from each side, suggesting local-scale climatic refugia in upwelling areas located inside marine protected areas. Southern recruits were more warm-tolerant but grew less at colder conditions than northern ones, revealing a mesoscale heterogeneity in thermal affinities. This study evidenced functional losses and distinct reproductive strategies experienced by F. guiryi at peripheral locations and urges to prioritize its conservation and restoration at contemporary climatic refugia.We thank the Plant Culture unit of SCAI-UMA for providing culture chambers, particularly Dr Lara Jim ́enez for her technical assistance. The authors thank the anonymous reviewer that helped us improve the first version of manuscript. Funding for open access charge: Universidad de Málaga / CBU
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