Congreso Internacional sobre Desertificación.
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- PublicationOpen AccessEl impacto de la ganadería y la agricultura en los ecosistemas terrestres.-The availability of water in ranches of mediterranean type climateS. Schnabel; Pulido Fernández, M.; Lavado Contador, J.F.; Universidad de MurciaABSTRACT A preliminary study on water resources for livestock rearing in SW Spain is presented. The objectives of this work were to assess the availability of water for domestic animals in farms and to explain whether water shortages are controlled by environmental factors or are also related with land management. The study was carried out in 54 private farms of wooded and treeless rangelands in Extremadura. Field work, digital topographic maps and aerial photographs were used to assess the potential hydrological resources of each farm. The water needs of livestock were estimated considering the number and species of animals per farm, as well as other factors influencing their water consumption. Furthermore, semistructured interviews were carried out in order to gather information about water management. Results indicate that almost 20% of the farms suffer problems of water availability in summer and almost 50% during droughts. Different solutions are adopted by the farmers, including construction of infrastructure, bringing water from outside or moving the animals to other areas. Data indicate a positive relationship between problems of water supply and the degree of aridity. Data also point to a relationship with water consumption by livestock and the availability of water by artificial ponds.
- PublicationOpen AccessEl impacto de la ganadería y la agricultura en los ecosistemas terrestres.-Desamortización e intensificación agraria de riberas fluviales: La vega de AranjuezLópez García, M.J.; Mateu Bellés, J. F.; Universidad de MurciaABSTRACT In Spain, successive appropriations by the state of river flood terraces which had previously been in communal or private hands led to –apart from notorious social repercussions– increased pressure on the limited water resources, loss of the diversity of agricultural uses as practices became more uniform, and accelerated destruction of the few remaining fragments of riverside woodlands. Later water laws (1866 and 1879) and court rulings permitted the aggregation of adjacent fields on river margins, the disappearance of customary uses (including settled and transhumant grazing) and the expansion of horticulture and other intensive arable crops. These changes in the middle of the nineteenth century provoked the loss of vegetation that, till then, had acted as a brake on the movement of peak flood flows whilst also flattening these peaks. This paper analyses the changes in a section of the Tajo-Jarama river valleys based on historical maps, and the IGN map series. The data show how the rate of change from natural terraces to cultivated terrain varied for different areas but was practically complete everywhere in the twentieth century. The model presented may be extrapolated to other rivers in the Iberian Peninsula indicating a process that could be relevant, together with other factors, in the interpretation of the magnitude and intensification of floods registered on the major rivers between the end of the nineteenth century and the beginning of the twentieth.
- PublicationOpen AccessEl impacto de la ganadería y la agricultura en los ecosistemas terrestres.-Influencia del sobrepastoreo en la producción de materia seca en agrosistemas pastorales extensivosLeco Berrocal, F.; Mateos Rodríguez, A. B.; Universidad de MurciaRESUMEN La utilización de imágenes de satélite junto con el trabajo de campo deben convertirse en un futuro muy inmediato en una de las técnicas y herramientas indispensables en cualquier estudio sobre la ordenación y planificación de los recursos naturales en el territorio, sobre todo cuando se trata de investigaciones relacionadas directamente con la cuantificación de la biomasa vegetal en el suelo no sólo para la gestión ganadera en agrosistemas silvopastorales extensivos, sino también para evaluar la capacidad de carga de esos agrosistemas en función de su producción real de biomasa. Las altas cargas ganaderas que mantienen estos ecosistemas, caso de los pastizales de la comarca de La Serena (Badajoz, Extremadura) con la especie ovina, están influyendo de manera decisiva en la producción anual de los pastos en una comarca con suelos pizarrosos y esqueléticos.
- PublicationOpen AccessEl impacto de la ganadería y la agricultura en los ecosistemas terrestres.-Grazing and soil erosion in dehesas of SW SpainSchnabel, S.; Gómez Gutiérrez, A.; Lavado Contador, J.F; Universidad de MurciaABSTRACT Water erosion and its relation to livestock grazing in semi-arid to dry subhumid Mediterranean rangelands with a disperse tree cover is analyzed, based on a variety of studies carried out since 1990 in Extremadura, Spain. The dominant factors of sheetwash are rainfall intensity and soil surface cover, the latter being controlled by rainfall amounts and livestock density. The discontinuous valley bottom gullies present a complex relationship with catchment hydrology. Giving the high temporal variability of sediment losses, the influence of livestock on gully erosion is difficult to determine with short-term studies. Analysis of aerial photographs (1945–2006) of the Parapuños study catchment point to an enhanced gully activity during the last decade as a consequence of increased livestock numbers.
- PublicationOpen AccessEl impacto de la ganadería y la agricultura en los ecosistemas terrestres.-Valorización agronómica de purines para su utilización en comúnGómez, M.; Estevez, M. D.; Faz, A.; Olivares, A. B.; Climent, V.ABSTRACT Due to the intensification of livestock production and the concentration of holdings in specific areas, has disrupted the balance between production and utilization of swine waste in agriculture. Given the volume of slurry generated in Murcia, and the total cultivable area and considering the legislation, RD 261/1996, which allows a maximum application of 170 kg N / ha / year in areas designated as vulnerable, it is estimated that to implement the slurry generated in the region in a year, would require only half the arable land devoted to irrigation. In this way, this study has included detailed monitoring of the effect of the application of pig slurry at a concentration recommended on the properties and chemical, physical and biological properties of soil, water and plant to determine the influence of slurry on the reserve of organic matter in each of these crops, as well as contaminated soils, through the creation of a pilot system for managing livestock waste in accordance with preventive measures that allow for their optimal use, without risk of contamination for the system watersoil- plant.