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15 results on '"Muriel, J.L."'

2. Calibración de sensores de humedad capacitivos usando redes neuronales

Author

Arriaga, J., Vanderlinden, Karl, Muriel, J.L., Morón, M., Gil Ortega Linares, Manuel, Rodríguez Rubio, Francisco, Universidad de Sevilla. Departamento de Ingeniería de Sistemas y Automática, European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER), and Comité Ético de Investigación Clínica (CEIC)

Subjects
Calibración, Redes neuronales, Sensores de humedad
Abstract

X Jornadas de Investigación de la Zona no Saturada del Suelo, Salamanca (España), 2011 El estudio de la variabilidad espacial de la humedad del suelo a escala de parcela o cuenca agrícola requiere el uso de redes de sensores de humedad de bajo coste, que suelen mostrar una fiabilidad limitada y requieren de calibraciones específicas, especialmente en suelos con elevados contenidos en arcilla. El presente trabajo pretende plantear una calibración más fiable de sondas de humedad mediante un análisis mixto campo-laboratorio. Para la calibración de campo se dispone de datos gravimétricos; para la calibración en laboratorio se han usado columnas de suelo inalterado que tras ser saturadas fueron desecadas en un entorno controlado mientras se monitorizaba la evolución de su peso y la de su humedad volumétrica, medida con diferentes sondas capacitivas Decagon. Tras obtener curvas de secado y la relación entre la humedad gravimétrica y la volumétrica es posible realizar una calibración mejorada específica para cada tipo de suelo. Las redes neuronales son particularmente útiles para el modelado de procesos físicos y el ajuste de modelos. En este trabajo se propone el empleo de dichas herramientas para obtener calibraciones para las sondas analizadas en el tipo de suelo objeto de estudio. Los resultados muestran que dichas calibraciones permiten mejorar la precisión de las mediciones de humedad realizadas. The study of the spatial variability of soil water content at agricultural plot or catchment scales requires the use of low-cost soil water content sensor networks, which usually show a limited reliability and require specific calibrations, specially for soils with a high clay content. This work proposes a more reliable calibration of soil water content probes with a laboratory analysis. Minimally disturbed soil columns were saturated with water and dried in a controlled environment while monitorizing the evolution of their volumetric soil water content (with different capacitive Decagon Probes) and weights. After obtaining the drying curves and the relation between the volumetric and the measured gravimetric soil water contents it is possible to achieve an improved calibration specific for different kinds of soil. Neural networks are especially interesting for the modeling of physical processes and model adjustment. In this work, these tools were used in order to obtain improved calibrations for the analyzed probes in the studied soil type. Results show that this calibration improves the accuracy and p Ministerio de Ciencia e Innovación AGL2009 C03-03 Junta de Andalucía AGR-4782

Published
2011

5. Calibración de sensores de humedad capacitivos usando redes neuronales

Author

Universidad de Sevilla. Departamento de Ingeniería de Sistemas y Automática, European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER), Comité Ético de Investigación Clínica (CEIC), Arriaga, J., Vanderlinden, Karl, Muriel, J.L., Morón, M., Gil Ortega Linares, Manuel, Rodríguez Rubio, Francisco, Universidad de Sevilla. Departamento de Ingeniería de Sistemas y Automática, European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER), Comité Ético de Investigación Clínica (CEIC), Arriaga, J., Vanderlinden, Karl, Muriel, J.L., Morón, M., Gil Ortega Linares, Manuel, and Rodríguez Rubio, Francisco

Abstract

El estudio de la variabilidad espacial de la humedad del suelo a escala de parcela o cuenca agrícola requiere el uso de redes de sensores de humedad de bajo coste, que suelen mostrar una fiabilidad limitada y requieren de calibraciones específicas, especialmente en suelos con elevados contenidos en arcilla. El presente trabajo pretende plantear una calibración más fiable de sondas de humedad mediante un análisis mixto campo-laboratorio. Para la calibración de campo se dispone de datos gravimétricos; para la calibración en laboratorio se han usado columnas de suelo inalterado que tras ser saturadas fueron desecadas en un entorno controlado mientras se monitorizaba la evolución de su peso y la de su humedad volumétrica, medida con diferentes sondas capacitivas Decagon. Tras obtener curvas de secado y la relación entre la humedad gravimétrica y la volumétrica es posible realizar una calibración mejorada específica para cada tipo de suelo. Las redes neuronales son particularmente útiles para el modelado de procesos físicos y el ajuste de modelos. En este trabajo se propone el empleo de dichas herramientas para obtener calibraciones para las sondas analizadas en el tipo de suelo objeto de estudio. Los resultados muestran que dichas calibraciones permiten mejorar la precisión de las mediciones de humedad realizadas., The study of the spatial variability of soil water content at agricultural plot or catchment scales requires the use of low-cost soil water content sensor networks, which usually show a limited reliability and require specific calibrations, specially for soils with a high clay content. This work proposes a more reliable calibration of soil water content probes with a laboratory analysis. Minimally disturbed soil columns were saturated with water and dried in a controlled environment while monitorizing the evolution of their volumetric soil water content (with different capacitive Decagon Probes) and weights. After obtaining the drying curves and the relation between the volumetric and the measured gravimetric soil water contents it is possible to achieve an improved calibration specific for different kinds of soil. Neural networks are especially interesting for the modeling of physical processes and model adjustment. In this work, these tools were used in order to obtain improved calibrations for the analyzed probes in the studied soil type. Results show that this calibration improves the accuracy and p

Published
2011

7. Steps toward an improvement in process-based models of water use by fruit trees: A case study in olive

Author

Diaz-Espejo, A., primary, Buckley, T.N., additional, Sperry, J.S., additional, Cuevas, M.V., additional, de Cires, A., additional, Elsayed-Farag, S., additional, Martin-Palomo, M.J., additional, Muriel, J.L., additional, Perez-Martin, A., additional, Rodriguez-Dominguez, C.M., additional, Rubio-Casal, A.E., additional, Torres-Ruiz, J.M., additional, and Fernández, J.E., additional

Published
2012
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14. Interpolation of Soil Moisture Content Aided by FDR Sensor Observations.

Author

Soares, Amílcar, Pereira, Maria João, Dimitrakopoulos, Roussos, Vanderlinden, K., Jiménez, J.A., Muriel, J.L., Perea, F., García, I., and Martínez, G.

Abstract

Automated soil moisture sensors are widely used in agronomy and environmental sciences. However, to sense properly the amount of water retained in the soil matrix, a calibration with gravimetrically observed values is required. This is laborious and not appropriate when the soil physical properties change during the wetting and drying cycles due to swelling and shrinkage, respectively. The objective of this study was to analyze how gravimetric soil moisture, θ, series can be interpolated from a minimum number of field observations, using daily automated sensor output as secondary information. Weekly observed soil moisture data from three depth intervals, and daily data from four sets for FDR sensors in two adjacent plots subject to different tillage practices were used to validate the method. A variogram analysis showed that soil moisture was more persistent in time and with depth in no-tillage and that at least two scales of temporal variation could be distinguished. Kriging with an external drift produced the largest model efficiency when using calibrated sensor measurements as secondary information. [ABSTRACT FROM AUTHOR]

Published
2008
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15. Water relations, growth and physiological response of seven strawberry cultivars (Fragaria × ananassa Duch.) to different water availability.

Author

Martínez-Ferri, E., Soria, C., Ariza, M.T., Medina, J.J., Miranda, L., Domíguez, P., and Muriel, J.L.

Subjects
*AGROHYDROLOGY, *CULTIVARS, *WATER supply, *WATER shortages, *IRRIGATION efficiency, STRAWBERRY growing
Abstract

Strawberry production requires the input of large amounts of water and its cultivation under plastic tunnels, relies entirely on water provided by irrigation during the production cycle. In these systems, water management is not easy, since soils are very poor and with low water holding capacity (sandy soils), and growers tend to use excessively and inadequately supplied water. This is especially tough at Huelva (the most important strawberry cropping area in Europe), where water is scarce and its use for irrigation is limited. Knowledge of water requirements of the main competitive strawberry cultivars of the region and their physiological and agronomical response to possible restrictions on water supply is required to keep its environmental sustainability. In this sense, no information pertaining to water requirements, crop-water use efficiency (WUE c ) and to the relative response to water shortage of the main strawberry cultivars currently growing in Huelva is available. Two experimental designs were carried out for the comparative evaluation of water requirements of seven strawberry cultivars ( Fragaria × ananassa Duch.) and of their physiological and growth response to water shortage (70% ETc). Main results showed that water consumption differs substantially among cultivars and these differences were associated with differences in the biomass partitioning into the harvest product (i.e. harvest index; HI) and in the transpiration efficiency of the standing biomass (TE v ) closely related to instantaneous water use efficiency ( A / T ). Cultivars were segregated on the basis of the relationship between both parameters, which integrate the differences among cultivars at the physiological (chlorophyll fluorescence, gas exchange, SPAD index, etc.) and at the growth response (fruit production, patterns of carbon allocation, LMA) levels in both water treatments. It is concluded that, in horticultural crops, such strawberry, greater leaf-level water use efficiency is not always an agronomical advantage in terms of water use. [ABSTRACT FROM AUTHOR]

Published
2016
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