Special issue on evapotranspiration measurement and modeling

Water availability for irrigation throughout the world has been reduced in recent years due to a combination of frequent droughts and competition for water resources among agricultural, industrial, and urban users. In addition, some major agricultural areas face moderate to significant reductions of rainfall, or changes in timing of stream flow due to changes in timing of snowmelt, as a result of global climate change. Under such conditions, sophisticated irrigation water management will be required to optimize water use efficiency and maintain sufficient levels of crop productivity and quality. A key factor to achieve these targets is the estimation of actual evapotranspiration (ET). Accurate determination of ET can be a viable tool in better utilization of water resources through well-designed irrigation management programs. Reliable estimates of ET are also vital to develop criteria for in-season irrigation management, water resource allocation, long-term estimates of water supply, demand and use, design and management of water resources infrastructure, and evaluation of the effect of land use and management changes on the water balance

Special issue on evapotranspiration measurement and modeling

Water availability for irrigation throughout the world has been reduced in recent years due to a combination of frequent droughts and competition for water resources among agricultural, industrial, and urban users. In addition, some major agricultural areas face moderate to significant reductions of rainfall, or changes in timing of stream flow due to changes in timing of snowmelt, as a result of global climate change. Under such conditions, sophisticated irrigation water management will be required to optimize water use efficiency and maintain sufficient levels of crop productivity and quality. A key factor to achieve these targets is the estimation of actual evapotranspiration (ET). Accurate determination of ET can be a viable tool in better utilization of water resources through well-designed irrigation management programs. Reliable estimates of ET are also vital to develop criteria for in-season irrigation management, water resource allocation, long-term estimates of water supply, demand and use, design and management of water resources infrastructure, and evaluation of the effect of land use and management changes on the water balance

USCID fourth international conference

Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.Includes bibliographical references.The two-layer model of Shuttlerworth and Wallace (SW) was evaluated to estimate actual evapotranspiration (ETa) above a drip-irrigated Merlot vineyard, located in the Talca Valley, Region del Maule, Chile (35° 25' LS; 71° 32' LW ; 136m above the sea level). An automatic weather system was installed in the center of the vineyard to measure climatic variables (air temperature, relative humidity, and wind speed) and energy balance components (solar radiation, net radiation, latent heat flux, sensible heat flux, and soil heat flux) during November and December 2006. Values of ETa estimated by the SW model were tested with latent heat flux measurements obtained from an eddy-covariance system on a 30 minute time interval. Results indicated that SW model was able to predict ETa with a root mean square error (RMSE) of 0.44 mm d-1 and mean absolute error (MAE) of 0.36 mm d-1. Furthermore, SW model predicted latent heat flux with RMSE and MAE of 32 W m-2 and 19W m-1, respectively

Water: tools and functions to estimate actual evapotranspiración using Land Surface Energy Balance Models in R

The crop water requirement is a key factor in the agricultural process. It is usually estimated throughout actual evapotranspiration (ETa). This parameter is the key to develop irrigation strategies, to improve water use efficiency and to understand hydrological, climatic, and ecosystem processes. Currently, it is calculated with classical methods, which are difficult to extrapolate, or with land surface energy balance models (LSEB), such as METRIC and SEBAL, which are based on remote sensing data. This paper describes water, an open implementation of LSEB. The package provides several functions to estimate the parameters of the LSEB equation from satellite data and proposes a new object class to handle weather station data. One of the critical steps in METRIC is the selection of “cold” and “hot” pixels, which water solves with an automatic method. The water package can process a batch of satellite images and integrates most of the already published sub-models for METRIC. Although water implements METRIC, it will be expandable to SEBAL and others in the near future. Finally, two different procedures are demonstrated using data that is included in water package.EEA MendozaFil: Olmedo, Guillermo Federico. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Ortega Farias, Samuel. Universidad de Talca. Centro de Investigación y Transferencia en Riego y Agroclimatología; ChileFil: Fuente Saiz, Daniel de la. Universidad de Talca. Centro de Investigación y Transferencia en Riego y Agroclimatología; ChileFil: Fonseca Luengo, David. Universidad de Talca. Centro de Investigación y Transferencia en Riego y Agroclimatología; ChileFil: Fuentes Peñailillo, Fernando. Universidad de Talca. Centro de Investigación y Transferencia en Riego y Agroclimatología; Chil

Evaluacion de un modulo predictivo de fenologia y evaluacion de madurez en Vitis vinifera L . (c.v. Cabernet Sauvignon)

Resumen (Spanish, English)59 p.Un estudio fue desarrollado para evaluar modelos predictivos de fenología y evolución de madurez en un viñedo ubicado en el valle de Pencahue (35° 15’ Latitud Sur; 71°45’ Longitud Oeste), durante la temporada 2000/01. Para este fin, se realizaron mediciones de temperatura y fenología (según la escala de Eichhorn y Lorenz (E-L) modificada por Coombe (1995)) y de evolución de madurez (Sólidos solubles, Acidez total y pH) en un cultivar Cabernet sauvignon sometido a tres niveles de reposición hídrica (40%, 70% y 100% de la evapotranspiración real de la vid) desde cuaja a cosecha. Para la predicción de fenología y evolución de madurez los modelos consideraron como variable de entrada los grados-día acumulados (base 10 °C). Los resultados de este estudio indicaron que el desarrollo fenológico entre las etapas de brotación y pinta no fue afectado por los distintos tratamientos de riego. No obstante, entre pinta y madurez de cosecha hubo diferencias altamente significativas entre los tratamientos de riego, donde los dos tratamientos con mayor restricción hídrica presentaron un adelanto de la madurez y mayor concentración de sólidos solubles. Los modelos predictivos de fenología y evolución de pH presentaron un buen comportamiento debido a que el error absoluto (Ea) entre los valores estimados y observados fue equivalente a un 1% y 3%, respectivamente. Además la desviación estándar del error (DEE) para la fenología y el pH fue de 1,99 y 0,12, respectivamente. Sin embargo, el modelo predictivo de evolución de acidez total presento el peor comportamiento con un Ea equivalente a un 25% y una DEE igual a 2.17 g/l H2SO4. Por su parte, el modelo predictivo de evolución de sólidos solubles presento una sobrestimación entre 17 y 22 °Brix y una buena comparación en la cosecha debido a que el Ea y DEE fueron equivalentes a 5% y 1,16 °Brix, respectivamente

Memoria del segundo simposium sobre historia, sociedad y cultura de México y América Latina

La presente obra reúne 20 ponencias de las 27 que se presentaron en el “Segundo simposium sobre historia, sociedad y cultura de México y América Latina”, realizado el 8 y 9 de noviembre de 2006, en el Centro de Investigación en Ciencias Sociales y Humanidades (CICSyH) de la Universidad Autónoma del Estado de México (UAEM), en Toluca, Estado de México

SELNET clinical practice guidelines for bone sarcoma

Bone sarcoma are infrequent diseases, representing < 0.2% of all adult neoplasms. A multidisciplinary management within reference centers for sarcoma, with discussion of the diagnostic and therapeutic strategies within an expert multidisciplinary tumour board, is essential for these patients, given its heterogeneity and low frequency. This approach leads to an improvement in patient's outcome, as demonstrated in several studies. The Sarcoma European Latin-American Network (SELNET), aims to improve clinical outcome in sarcoma care, with a special focus in Latin-American countries. These Clinical Practice Guidelines (CPG) have been developed and agreed by a multidisciplinary expert group (including medical and radiation oncologist, surgical oncologist, orthopaedic surgeons, radiologist, pathologist, molecular biologist and representatives of patients advocacy groups) of the SELNET consortium, and are conceived to provide the standard approach to diagnosis, treatment and follow-up of bone sarcoma patients in the Latin-American context