APLICACIÓN DE ULTRASONIDOS PARA EL CONTROL DE ALGAS EN AGUAS REGENERADAS ALMACENADAS EN BALSAS DE RIEGO

[ES] En las regiones áridas y semiáridas las balsas de riego son infraestructuras que garantizan el suministro de agua a los cultivos. Sin embargo, favorecen la proliferación de algas provocando serios problemas en la calidad del agua que afectan negativamente a los sistemas de riego (filtración, emisores, elementos auxiliares,...). Ante esta problemática, el objetivo de este estudio fue evaluar, a escala real, el efecto de los ultrasonidos sobre parámetros físico-químicos y microbiológicos de interés agronómico en el agua de riego almacenada y sobre la presencia de algas en el agua. El ensayo se realizó en tres balsas de aguas regeneradas y una de agua suministrada por la Comunidad de Regantes del Campo de Cartagena, principalmente procedente del Trasvase Tajo-Segura. Equipos de emisión de ultrasonidos se instalaron en 2 de las 4 balsas para tratar de reducir la presencia de algas. Quincenalmente, se determinó la calidad del agua mediante una sonda multiparamétrica y el análisis de muestras de agua en laboratorio. Los resultados del experimento manifiestan que los ultrasonidos controlan el crecimiento de microalgas manteniendo la concentración de éstas en valores aceptables para evitar problemas de obturación en los sistemas de riego y mejorando por tanto la calidad del agua almacenada.Maestre Valero, J.; Pedrero Salcedo, F.; Soto García, M.; Alarcón, J. (2015). APLICACIÓN DE ULTRASONIDOS PARA EL CONTROL DE ALGAS EN AGUAS REGENERADAS ALMACENADAS EN BALSAS DE RIEGO. En XXXIII CONGRESO NACIONAL DE RIEGOS. Valencia 16-18 junio de 2015. Editorial Universitat Politècnica de València. https://doi.org/10.4995/CNRiegos.2015.1439OC

Caracterización del suministro de agua marina desalinizada para riego en el sureste español

Comunicación presentada al XXXVII Congreso Nacional de Riegos, celebrado en Don Benito del 4 al 6 de Junio de 2019 y organizada por la Asociación Española de Riegos y Drenajes y la Universidad de ExtremaduraLa actual escasez de recursos hídricos en las regiones áridas y semiáridas del sureste español ha impulsado la utilización de fuentes no convencionales, como la reutilización de aguas regeneradas y la desalinización de agua marina, especialmente en la agricultura de regadío. Como consecuencia, en esta región se está utilizando para riego agrícola casi el 100% del volumen de agua regenerada (105 hm3/año), así como cerca de 180 hm3/año de Agua Marina Desalinizada (AMD). Este trabajo describe la situación del suministro de AMD para riego en el sureste español, una región donde hasta el momento ha tenido un gran desarrollo. Se analizan en primer lugar los factores que justifican esta nueva alternativa de suministro hídrico para el regadío como estrategia para garantizar la producción de alimentos y el desarrollo socioeconómico regional. A continuación, se abordan cuestiones clave para analizar la sostenibilidad ambiental y económica del suministro de AMD en el medio y largo plazo, como son el consumo energético asociado a su producción y distribución, los costes asociados, y el precio final que tienen que asumir los agricultores.• Ministerio de Economía y Competitividad y el Fondo Europeo de Desarrollo Regional: Proyecto RIDESOST (AGL2017-85857-C2-2-R) • Programa LIFE de la Unión Europea: Proyecto DESEACROP (LIFE16-ENV_ES_000341

Effects of drip irrigation systems on the recovery of dissolved oxygen from hypoxic water

The dissolved oxygen concentration (DOC) is an important irrigation water quality parameter that can become a limiting factor in some intensive agriculture systems. A low DOC in the irrigation water may have critical consequences because it causes root oxygen deficiency, which in turn can result in agronomic problems. The aim of this study was to improve the understanding of the dynamics of the DOC in hypoxic irrigation water when passing throughout a surface drip irrigation system (DIS) and seeping into the soil. To this end, an experimental DIS consisting of three types of commercial emitters and a venturi air injector, installed in-line, was set up for evaluation. Furthermore, subsurface water samplers were buried to catch the water in the soil. The trials were conducted with water from two different sources. The control treatment was performed with fresh channel water, which had a high DOC (7.54 mg L-1; 92.2% saturation), and the low DOC treatments were supplied from a covered agricultural reservoir and had DOC values less than 1.08 mg L-1 (10.8% saturation). After the low DOC treatments, the final DOC in the soil 24 h after irrigation ranged from 3.77 mg L-1 to 5.31 mg L-1 (47.2% to 65.2% saturation). There was an increase in the DOC in all stages of the experimental DIS, which was more important in the water passing through the emitters. The main factor determining the final DOC was the type of emitter, where DOC differences were correlated to their flow performance. The control treatment reached a similar DOC in the soil 24 h after irrigation, indicating that using hypoxic water under DIS does not affect the final soil DOC. Finally, the application of a venturi air injector increased the DOC in the low DOC source up to values typically found in open channels and reservoirs.Water quality Drip irrigation Water oxygation Emitters Venturi air injector Shade-cloth cover

Estimation of dew yield from radiative condensers by means of an energy balance model

This paper presents an energy balance modelling approach to predict the nightly water yield and the surface temperature (Tf) of two passive radiative dew condensers (RDCs) tilted 30º from horizontal. One was fitted with a white hydrophilic polyethylene foil recommended for dew harvest and the other with a black polyethylene foil widely used in horticulture. The model was validated in south-eastern Spain by comparing the simulation outputs with field measurements of Tf and dew yield. The results indicate that the model is robust and accurate in reproducing the behaviour of the two RDCs, especially in what refers to Tf, whose estimates were very close to the observations. The results were somewhat less precise for dew yield, with a larger scatter around the 1:1 relationship. A sensitivity analysis showed that the simulated dew yield was highly sensitive to changes in relative humidity and downward longwave radiation. The proposed approach provides a useful tool to water managers for quantifying the amount of dew that could be harvested as a valuable water resource in arid, semiarid and water stressed regions

Economic assessment of shade-cloth covers for agricultural irrigation reservoirs in a semi-arid climate

We assess the economics of investing in suspended shade-cloth covers (SSCCs) in agricultural water reservoirs (AWRs) to reduce evaporation losses and save water for irrigation in arid and semi-arid areas. In particular, we examine the use of SSCCs in the Segura River Basin (southeastern Spain). The decision to install a cover depends on the potential evaporation losses, reservoir characteristics, cover effectiveness, the value of water, filtration requirements, water salinity, government subsidies and the installation, operation and maintenance costs. The economic viability of the investment increases with the value of the saved water, i.e., with water scarcity, and is greater when water quality is poor. Hence SSCCs can be helpful in arid and semi-arid regions facing water shortages and water quality problems. The farm-level decision to install a cover depends largely on the cost of purchasing water, when water is generally available, and the profit from increased crop production or enlarged farmlands, when water is scarce.Water saving Evaporation losses Salinity Filtration Spain

Outcomes in Neurosurgical Patients Who Develop Venous Thromboembolism

International audienceOBJECTIVES: Registro Informatizado de Enfermedad TromboEmbólica (RIETE) database was used to investigate whether neurosurgical patients with venous thromboembolism (VTE) were more likely to die of bleeding or VTE and the influence of anticoagulation on these outcomes.METHODS:Clinical characteristics, treatment details, and 3-month outcomes were assessed in those who developed VTE after neurosurgery.RESULTS: Of 40 663 patients enrolled, 392 (0.96%) had VTE in less than 60 days after neurosurgery. Most patients in the cohort (89%) received initial therapy with low-molecular-weight heparin, (33% received subtherapeutic doses). In the first week, 10 (2.6%) patients died (8 with pulmonary embolism [PE], no bleeding deaths; P = .005). After the first week, 20 (5.1%) patients died (2 with fatal bleeding, none from PE). Overall, this cohort was more likely to develop a fatal PE than a fatal bleed (8 vs 2 deaths, P = .058).CONCLUSIONS: Neurosurgical patients developing VTE were more likely to die from PE than from bleeding in the first week, despite anticoagulation