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Los páramos son ecosistemas de montaña capaces de ofrecer gran variedad de funciones y servicios al hombre, dentro de las más importantes se resalta la regulación hídrica, gracias a las características de cobertura vegetal y altitud. El cambio climático y la intervención del hombre en cuanto a minería, agricultura y ganadería, han venido generando como consecuencia un alto grado de degradación ambiental. Disminuyendo así, sus principales funciones como la retención de agua y la infiltración. Este trabajo investigativo logró determinar la identificación de las zonas prioritarias de recuperación y las posibles medidas para tal fin. Lo anterior se pudo concretar mediante el procesamiento de imágenes satelitales, la delimitación de la subcuenca, la clasificación y caracterización de los suelos, en función a la variación del cambio de cobertura vegetal a través del tiempo y del uso de literatura para la recuperación de ecosistemas de alta montaña. El análisis multitemporal de las imágenes satelitales confirmó que la intervención del hombre en los ecosistemas de alta montaña causa un grave deterioro de la cobertura vegetal y con ello la degradación de la vegetación nativa del lugar, dando lugar a fenómenos que alteran los servicios que los ecosistemas prestan al medio ambiente y al ser humano. Se pudo determinar que la cobertura vegetal que sufrió en grandes extensiones un deterioro considerable fue la vegetación de páramo, con una disminución del 14.8 %. El arbustal bajo disminuyó su extensión en 7.3 % y el bosque mixto se redujo en un 2.3 %. Se observó que donde disminuyeron las coberturas nativas ahora se encuentran vegetaciones relacionadas con los factores antrópicos, como lo son los cultivos. Dichas adapciones de los ecosistemas aumentaron en un 14 %. La ganadería es otro disturbio que está dejando consecuencias nefastas para la zona de estudio, debido al incremento de su cobertura en un 11.4 % y, como consecuencia de esta expansión, los suelos desnudos se han ampliado en un 0.8 %. Palabras clave: páramo, cobertura vegetal, imágenes satelitales, plan de acción. The moors are mountain ecosystems capable of offering a great variety of functions and services to man, the most important of which are water regulation, thanks to the characteristics of vegetation cover and altitude. Climate change and the intervention of man in terms of mining, agriculture and livestock have been generating as a consequence a high degree of environmental degradation. Thus decreasing its main functions such as water retention and infiltration. This investigative work was able to determine the identification of priority recovery areas and possible measures for this purpose. The foregoing could be specified through the processing of satellite images, the delimitation of the sub-basin, the classification and characterization of the soils, based on the variation in the change of vegetation cover over time and the use of literature for the recovery of ecosystems. high mountain. The multitemporal analysis of the satellite images confirmed that the intervention of man in the high mountain ecosystems causes a serious deterioration of the vegetation cover and with it the degradation of the native vegetation of the place, giving rise to phenomena that alter the services that the ecosystems lend to the environment and humans. It was determined that the vegetation cover that suffered a considerable deterioration in large areas was the páramo vegetation, with a decrease of 14.8%. The low shrubland decreased in extension by 7.3% and the mixed forest was reduced by 2.3%. It was observed that where native covers decreased, now there are vegetations related to anthropic factors, such as crops. These ecosystem adaptations increased by 14%. Livestock is another disturbance that is leaving dire consequences for the study area, due to the increase in its coverage by 11.4% and, as a consequence of this expansion, bare soils have expanded by 0.8%. Keywords: páramo, vegetation cover, satellite images, action plan. http://www.ustatunja.edu.co/investigacion Pregrado

With the arable land use intensification in recent decades, depletion of soil fertility and soil erosion have emerged as major issues for the sustainability of agricultural production systems in New Caledonia. Like other islands in the South Pacific, agricultural intensification has had positive impacts on agricultural production and food security but also detrimental impacts on biodiversity, soil, and water resources. New cropping system management is needed to better manage ecological functions and ultimately, enhance the provision of ecosystem services. Conservation agriculture (CA) is a farming system based on minimum soil disturbance (i.e., no tillage), maintenance of a permanent soil cover, and diversification of plant species. CA practices are a promising way to reduce the negative impacts of agriculture, especially on soil, while conserving production and ecosystem services. In this study, we propose an original framework based on integrative and systemic approaches of the relationships between agricultural practices, ecological functions, and cropping system performances. The study was conducted on the West coast of New Caledonia and three questions were addressed to assess the impacts of CA on the provision of ecosystem services: i) what are the impacts of CA on soil health and cropping system performances compared with conventional tillage (CT)?, ii) what are the impacts of CA on functional biodiversity (soil macrofauna)?, and iii) what are the resource use efficiency and cropping system performances of intercropping systems compared to maize monoculture? To answer the first two questions, a long-term experiment was started in 2011 to compare three maize-based cropping systems: i) mono-cropping under CT, which is the predominant practice in the region, ii) CA with direct seeding of maize in a dead mulch (a mixture of four annual species) (CA-DM), and iii) CA with direct seeding of maize in a living mulch (Stylosanthes guianensis) (CA-LM). Furthermore, an analytical experiment was conducted in 2018 to assess the impacts of a maize-Stylosanthes guianensis intercropping system on resource use efficiency and productivity compared to monoculture. On the one hand, the impact of the three contrasted cropping systems (i.e., CT, CA-DM and CA-LM) on soil health were assessed and compared using Biofunctool®. Biofunctool® is a functional assessment of soil health based on an integrative approach taking into account the links between the physico-chemical properties and the biological activity of soils. It allows an analysis of the three main functions of the soil: i) carbon transformation, ii) nutrient cycling, and iii) soil structure maintenance. On the other hand, a soil macrofauna services (SMS) index was proposed as an integrative tool to evaluate and compare the effects of these cropping systems on soil macrofauna services. This index integrates three key macrofauna functions: i) decomposition of organic matter, ii) ecosystem engineering, and iii) pest control. Finally, the resource use efficiency (i.e., water, light, nitrogen and land) and the performance of intercropping systems were assessed and compared with monoculture., La dégradation des terres liée à l'intensification agricole, principalement due à la baisse de la fertilité des sols et à l’érosion, est devenue une problématique majeure en Nouvelle-Calédonie. Le contexte insulaire et les spécificités pédoclimatiques rendent en outre les enjeux d’autosuffisance alimentaire, de préservation des agroécosystèmes et de la biodiversité, d’autant plus prégnants. Les systèmes de culture (sdc) doivent donc évoluer en mobilisant les processus biologiques afin d’être viables, performants et durables. L’agriculture de conservation (AC) consiste en un ensemble de pratiques culturales basé sur trois principes : une réduction, voire une suppression du travail du sol, une couverture végétale du sol permanente et une diversification des espèces cultivées. L’AC peut répondre à ces problématiques en alliant durabilité et productivité, et en favorisant un certain nombre de services écosystémiques. A travers une démarche originale intégrant approches fonctionnelle et systémique, cette thèse vise à quantifier les relations entre pratiques, fonctions et services écosystémiques au sein de sdc complexes. Dans le contexte spécifique de la côte ouest de la Nouvelle-Calédonie, afin de savoir si l’AC pourrait maximiser la fourniture de services écosystémiques, trois questions sont apparues importantes à aborder : quels sont les impacts des pratiques de l’AC sur la santé du sol et les performances agronomiques de sdc ?, quels sont les effets de l’AC sur la biodiversité fonctionnelle (macrofaune) ?, et quelles sont les performances et l’efficience d’utilisation des ressources de sdc en AC notamment sous couvert végétal vivant ? Afin de répondre aux deux premières questions, une expérimentation système, initiée en 2011, a permis de comparer en 2018 trois sdc en production de maïs : un sdc en monoculture et en labour, représentant la pratique de référence de la région (CT), un sdc en AC sous couvert végétal mort (mélange de 4 espèces annuelles) (CA-DM), et un sdc en AC sous couvert végétal vivant (Stylosanthes guianensis) (CA-LM). Une expérimentation analytique a également été mise en place en 2018 afin d’évaluer les performances et l’efficience d’utilisation des ressources d’une association maïs-Stylosanthes guianensis en AC sous couvert végétal vivant. D’une part, l’impact du mode de conduite de ces trois sdc sur la santé du sol a été caractérisé via l’utilisation de Biofunctool®. Biofunctool® est une méthode d’évaluation fonctionnelle de la santé des sols basée sur une approche intégrative prenant en compte les liens entre les propriétés physico-chimiques et l'activité biologique des sols. Elle permet de mener une analyse des fonctions principales du sol : i) la transformation du carbone, ii) le recyclage des nutriments, et iii) le maintien de la structure du sol. D’autre part, un outil fonctionnel (SMS) est proposé afin de mesurer l’impact de pratiques culturales sur l’activité de la macrofaune du sol. Il permet d’intégrer trois fonctions de la macrofaune : i) la dégradation de la matière organique, ii) l’ingénierie de l’écosystème, et iii) la régulation des ravageurs. Enfin, l’évaluation de l’efficience d’utilisation des ressources (i.e., eau, azote, lumière, surface) et des performances de ces sdc contrastés a été menée à l’aide de la modélisation par équations structurelles.

In this paper a recently theoretically deduced flow resistance equation, based on a power-velocity profile, was tested using data collected for overland flow under simulated rainfall carried out in plots with vegetation. The available data were obtained exploring a wide range of rainfall intensities (from 60 to 181 mm h−1) and slopes (from 3.6 to 39.6%), and with four different types of vegetation. The database, including measurements of flow velocity, water depth, cross sectional flow area, wetted perimeter and bed slope, was divided in four datasets (one for each vegetation type), which allowed the calibration of the relationship between the velocity profile parameter Γ, the slope steepness, the flow Froude number, and the rainfall Reynolds number. The effect of rainfall intensity and different types of vegetation on flow resistance was investigated. The results showed that the theoretically deduced flow resistance equation allowed an accurate estimate of the Darcy-Weisbach friction factor for overland flow under simulated rainfall and in presence of vegetation. The developed analysis also suggested that flow resistance increases with rainfall intensity for laminar overland flow. The available data demonstrated that a quasi-independence between slope and mean velocity occurred. Finally, a single flow resistance equation resulted applicable to all investigated vegetation types and this equation was affected by flow regime represented by flow Reynolds number.

Los páramos son entornos, cuyo servicio ecosistémico es la regulación hídrica, en el cual juega un rol importante la cobertura vegetal y el uso de su suelo. Sin embargo, estos sistemas han presentado un alto grado de degradación, como consecuencias de la variación de la cobertura, por producto del cambio climático y actividades antrópicas, tales como: explotación minera, ganadería, agricultura y deforestación que generan una disminución en la capacidad de retención de agua e infiltración, afectando la función ambiental de los páramos como reguladores hídricos. Es por esto que esta investigación busca analizar los efectos generados sobre los páramos Tota – Bijagual – Mamapacha, a través del análisis y modelamiento hídrico de las subcuencas del Municipio de Tota durante el periodo comprendido entre 1986-2015. Este proyecto tiene dos grandes etapas, la etapa I consiste en el análisis multitemporal del cambio de la cobertura vegetal a través de imágenes tipo landsat con características de calidad que permitan el correcto análisis de las mismas y la etapa II evalúa la alteración de la respuesta hídrica empleando el mapa de la geología para la zona de estudio proporcionados por el atlas geológico Colombiano y atlas geológico mundial de la FAO-UNESCO y utilizando datos climatológicos suministrados por el IDEAM , donde se genera el modelo hidrológico para posterior calibración empreando Swat-Cup por medio del modelo matemático Sufi2, permitiendo analizar el comportamiento de la respuesta hídrica durante el periodo de estudio y cambios de la cobertura vegetal. The páramos are environments, whose ecosystem service is the water regulation, in which the vegetal cover and the use of its soil play an important role. However, these systems have presented a high degree of degradation, as a consequence of the variation of the coverage, by the product of the climatic change and anthropic activities, such as: mining, livestock, agriculture and deforestation that generate a decrease in the capacity of water retention and infiltration, affecting the environmental function of the páramos as water regulators. This is why this research has the objective of evaluating the alteration in the water response, in the subbasins, Lake of Tota, Desaguadero River, Fishing River, Rio Lengupa and Quebrada el chuque, during the period 1986-2015. The project has two major stages, the first is the multitemporal analysis of the change of vegetation cover, through lansdat images and applying the unsupervised classification method and homogenizing the information according to the SWAT software soil cover classification, taking into account that the years of analysis of the vegetation coverage 1986, 1989, 1992, 2000, 2003, 2007, 2012 and 2015 yielded different changes with respect to the damages caused by various environmental damages, the paramo area suffered losses of 19,596.65 Ha during the period studied but nonetheless during the course of the years there was a notable recovery of this coverage by 98%. The second stage evaluates the alteration in the water response, through the study of the rainfall - runoff relationship, in each of the years that the vegetation cover was evaluated, physiological characteristics of the micro - basins and hydroclimatic data, using the SWAT software. Pregrado

Los principales disturbios que afectan los mallines en Patagonia están vinculados con alteraciones en su dinámica hídrica y el pastoreo intensivo y continuo durante períodos prolongados (Raffaele, 1999). Estos disturbios fueron provocando en éstos ambientes procesos de degradación por disminución de la cobertura aérea vegetal, erosión hídrica por escurrimiento superficial resultante en surcos y cárcavas, salinización debido a la alta evaporación de agua y compactación del suelo por efecto del pisoteo animal (Bonvissutto et al., 1992; Del Valle, 1993). Existen antecedentes de indicadores cuantitativos de deterioro para los mallines de Santa Cruz, a partir de claves objetivas para la caracterización cuantitativa del nivel de deterioro o condición de los mallines como herramienta para la toma de decisiones al momento de planificar su uso (Suárez et al., 2010; Ormaechea et al., 2010). Sin embargo, es importante determinar las causas que resultan en distintas condiciones de degradación considerando variables de la vegetación, suelo y agua. Estos estudios deberían colaborar en generar acciones de mitigación que resulten en un uso ganadero más sustentable del pastizal, suelo y agua de éstos ambientes (Bran, 2009). EEA Santa Cruz Fil: Utrilla, Víctor Ricardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz. Grupo Producción Agropecuaria; Argentina. Fil: Utrilla, Víctor Ricardo. Universidad Nacional de la Patagonia Austral. Unidad Académica Río Gallegos; Argentina. Fil: Andrade, Miguel Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina Fil: Andrade, Miguel Alberto. Universidad Nacional de la Patagonia Austral. Unidad Académica Río Gallegos; Argentina. Fil: Billoni, Sabrina L. Universidad Nacional de la Patagonia Austral. Unidad Académica Río Gallegos; Argentina. Fil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina. Fil: Peri, Pablo Luis. Universidad Nacional de la Patagonia Austral; Argentina. Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fil: Sturzenbaum, Maria Virginia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina. Fil: Rogel, Bibiana. Universidad Nacional de la Patagonia Austral. Unidad Académica Río Gallegos; Argentina.

The objective of this work was to evaluate the alterations in carbon and nitrogen mineralization due to different soil tillage systems and groundcover species for intercropped orange trees. The experiment was established in an Ultisol soil (Typic Paleudults) originated from Caiuá sandstone in northwestern of the state of Paraná, Brazil, in an area previously cultivated with pasture (Brachiaria humidicola). Two soil tillage systems were evaluated: conventional tillage (CT) in the entire area and strip tillage (ST) with a 2-m width, each with different groundcover vegetation management systems. The citrus cultivar utilized was the 'Pera' orange (Citrus sinensis) grafted onto a 'Rangpur' lime rootstock. The soil samples were collected at a 0-15-cm depth after five years of experiment development. Samples were collected from under the tree canopy and from the inter-row space after the following treatments: (1) CT and annual cover crop with the leguminous Calopogonium mucunoides; (2) CT and perennial cover crop with the leguminous peanut Arachis pintoi; (3) CT and evergreen cover crop with Bahiagrass Paspalum notatum; (4) CT and cover crop with spontaneous B. humidicola grass vegetation; and (5) ST and maintenance of the remaining grass (pasture) of B. humidicola. The soil tillage systems and different groundcover vegetation influenced the C and N mineralization, both under the tree canopy and in the inter-row space. The cultivation of B. humidicola under strip tillage provided higher potential mineralization than the other treatments in the inter-row space. Strip tillage increased the C and N mineralization compared to conventional tillage. The grass cultivation increased the C and N mineralization when compared to the others treatments cultivated in the inter-row space. No presente trabalho, foi avaliada a mineralização do Carbono e Nitrogênio devido ao cultivo intercalar de diferentes coberturas permanentes em pomar de laranjeira. O experimento foi conduzido no noroeste do Paraná, em um Argissolo Vermelho distrófico latossólico de textura arenosa/média originado do arenito Caiuá, em área previamente ocupada por pastagem (Brachiaria humidicola). Foram estudados dois sistemas de preparo do solo (preparo convencional [PC] e preparo em faixa [PF]) e diferentes coberturas intercalares em plantas de citros. Foi utilizada a laranja 'Pera' (Citrus sinensis) enxertada em limoeiro 'Cravo' (Citrus limonia). As amostras de solos foram coletadas cinco anos após a instalação do experimento, na profundidade de 0-15 cm, sob a projeção da copa e na entrelinha, nos seguintes tratamentos: (1) PC e cobertura vegetal com a leguminosa anual Calopogonium mucunoides; (2) PC e cobertura vegetal com a leguminosa perene amendoim forrageiro Arachis pintoi; (3) PC e cobertura vegetal com gramínea mato-grosso ou batatais Paspalum notatum; (4) PC e cobertura com vegetal espontânea da gramínea Brachiaria humidicola; (5) PF e manutenção da gramínea remanescente da pastagem, Brachiaria humidicola. O preparo do solo e as diferentes coberturas vegetais influenciaram na mineralização do C e N tanto na projeção da copa como na entrelinha. O cultivo de Brachiaria sob preparo em faixa proporcionou aumento na mineralização do C e N na entrelinha, comparado aos outros tratamentos. O preparo em faixa aumentou a mineralização de C e N quando comparado ao preparo convencional. O cultivo de gramíneas aumentou a mineralização de C e N na entrelinha.

Le Centre de Stockage de la Manche est le premier centre français de stockage des déchets radioactifs. Les déchets sont enfouis à plusieurs mètres de profondeur et protégés par un concept de couverture multicouches, imperméable, muni d'un système de drainage. En surface, la couverture est occupée par une végétation de type prairial. Une expertise scientifique a été menée par le laboratoire Géophen de l'université de Caen afin de mieux caractériser ce couvert végétal (groupes écologiques et sols associés) et voir comment il est susceptible d'évoluer à plus ou moins long terme. Les résultats montrent quels pourraient être les scénarios les plus probables d'évolution et les alternatives de gestion.