15 research outputs found

    Empleo de imágenes térmicas obtenidas mediante UAVs para la determinación del estrés hídrico en Vitis Vinífera (CV. Albariño)

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    El manejo del riego en viñedo es un aspecto crítico para obtener un producto de calidad, requiriéndose herramientas que permitan conocer el estrés hídrico en tiempo real, para gestionar la cantidad y el momento de riego adecuados. La termografía del dosel vegetal obtenida mediante vuelos no tripulados permite obtener la distribución espacial para el conjunto del viñedo en un momento determinado, por lo que su interrelación con los parámetros clásicos de manejo del riego: contenido de agua en el suelo y potencial hídrico foliar de tallo, se presenta como aspecto crítico para facilitar su implementación como herramienta. En el presente estudio se exponen los resultados de la termografía del dosel de Vitis vinífera cv. Albariño durante el envero del año 2015, en una espaldera con diferentes tratamientos de fertirriego. Se muestra una buena correlación entre el contenido de agua en suelo y la temperatura mínima del dosel vegetal (r = 0,57), lo que permite gestionar el estado hídrico del viñedo, siendo preciso emplear las relaciones existentes entre el contenido de agua en el suelo y el potencial hídrico foliar, obtenidas previamente para la variedad y la zona de estudio por Martínez et al., (2016).Vineyard irrigation management is critical for obtain a quality product, requiring tools to determine water stress in real-time, to manage the irrigation depth and appropriate irrigation time. Plant canopy thermography obtained by unmanned aerial vehicles (UAV) allows to obtain the spatial distribution for the whole vineyard at a certain period, so their interrelationship with the classical parameters of irrigation management: soil water content and stem-leaf water potential, it is presented as critical aspect to facilitate its implementation as a tool. Thermography canopy results are showed in the present study for Vitis vinifera cv Albariño, during veraison 2015, on a trellis system with different fertigation treatments. Good correlations were achieved, between the soil water content and minimum temperature of canopy (r = 0.57), allowing vineyard water status management, however it is necessary to use the relationship between the soil water content stem-leaf water potential, previously obtained for the variety and the area of study by Martinez et al., (2016)

    Impact of adherence on growth response during the first 2 years of growth hormone treatment

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    Purpose Adherence to growth hormone (GH) treatment impacts clinical outcomes. The aim of this study is to assess the impact of adherence to rhGH treatment (2 years) on auxological outcomes. Methods Multicentric, retrospective observational study in rhGH-naive GHD/SGA children treated with Saizen (R) during >= 2 years. Growth response was assessed by evaluating the change in height standard deviation score (Delta H SDS) and the index of responsiveness (IoR). Adherence was monitored using EasyPod (TM) Connect device. Results A total of 110 patients (3 Spanish centers) were evaluable (GHD n = 76, SGA n = 34). Adherence was 95.6 and 93.9% (year 1, 2). SGA and GHD children showed an increase of 0.6 cm/year and 1.1 cm/year for each 10% adherence modification. Lower adherence was observed in patients with lower pretreatment height velocity (HV) and in patients whose parents had a lower level of education. A positive correlation between index of responsiveness (IoR) during the first and second years with HV SDS during the second year and between IoR2 and adherence (year 1, 2) was observed. The frequency of patients with HV > 1 SD was higher (p = 0.025) among patients with adherence >90%. The best model to predict the height gain(cm) reaching an adjusted R squared of 0.489 involved percentage of adherence, Tanner stage, pretreatment HV, dose of rhGH, and whether the treatment was initiated before or after puberty. Conclusions Adherence during the first 2 years of response was very high >90% and showed a negative association with age, pretreatment HV and treatment duration and a positive correlation with the level of parent education

    Frecuencia de riego en variedades tintas: Repercusión en la producción y la composición de la uva, durante un periodo bienal, en 4 regiones de España

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    Resumen La restricción hídrica es un aspecto limitante del cultivo del viñedo en muchas regiones, por lo que el riego constituye uno de los principales factores determinantes de su desarrollo en muchas zonas, que ha sido estudiado en diferentes ámbitos, pero la frecuencia de aplicación del riego, que afecta a su distribución en el suelo y puede influir en el comportamiento del viñedo, no ha sido suficientemente evaluada, por lo que su estudio resulta de gran interés en diversas condiciones de cultivo. El objetivo de este trabajo fue evaluar los efectos de cuatro frecuencias de riego deficitario del 30% ET0: 7 riegos por semana (T01), 2 riegos por semana (T03), 1 riego por semana (T07) y 1 riego cada dos semanas (T15), en la producción de uva y la composición de la baya. El experimento se desarrolló durante los años 2021 y 2022, en viñedos de Garnacha Tinta (en Badajoz: T03, T07, T15), Tempranillo (en Valladolid: T03, T07, T15), Syrah (en Albacete: T03 y T07) y Mencía (en Lugo: T01, T03, T07). Tanto la producción como la composición de la uva fueron determinadas en vendimia. Las diferentes frecuencias de riego han repercutido en el rendimiento y la calidad de la uva de forma variable según la variedad, la localización y el año. La producción de uva y la madera de poda se vieron ligeramente favorecidos por la frecuencia T07 con respecto a T03 en Garnacha y, sólo en la producción, en Tempranillo, mientras que ocurrió lo contrario en Syrah y Mencía. La concentración de azúcares se vio ligeramente favorecida por la frecuencia T07 en Syrah y, parcialmente, en Tempranillo. El pH del mosto no ofreció una respuesta apreciable derivada de la frecuencia de riego. La acidez total mostró valores ligeramente superiores de T07 en Garnacha y Tempranillo, pero algo más altos de T03 en Syrah y Mencía. El ácido tartárico apenas presentó una ligera tendencia favorable a T07 en Garnacha, mientras que el ácido málico mostró una tendencia ligeramente favorable a T07 en Garnacha y Mencía, pero beneficiosa para T03 en Syrah. El contenido de potasio y de polifenoles totales ofreció una clara variabilidad entre frecuencias de riego en general, aunque el primero mostró un ligero aumento del T03 con respecto al T07 en Mencía y el segundo un ligero aumento del T07 frente al T03 en Syrah. En definitiva, los efectos productivos y cualitativos derivados de la frecuencia de riego aplicada han tenido un alcance reducido, que, sin embargo, puede variar moderadamente en función de la variedad y del año

    Prediction of crop coefficients from fraction of ground cover and height. Background and validation using ground and remote sensing data

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    ReviewThe current study aims at reviewing and providing advances on methods for estimating and applying crop coefficients from observations of ground cover and vegetation height. The review first focuses on the relationships between single Kc and basal Kcb and various parameters including the fraction of ground covered by the canopy (fc), the leaf area index (LAI), the fraction of ground shaded by the canopy (fshad), the fraction of intercepted light (flight) and intercepted photosynthetic active radiation (fIPAR). These relationships were first studied in the 1970’s, for annual crops, and later, in the last decennia, for tree and vine perennials. Research has now provided a variety of methods to observe and measure fc and height (h) using both ground and remote sensing tools, which has favored the further development of Kc related functions. In the past, these relationships were not used predictively but to support the understanding of dynamics of Kc and Kcb in relation to the processes of evapotranspiration or transpiration, inclusive of the role of soil evaporation. Later, the approach proposed by Allen and Pereira (2009), the A&P approach, used fc and height (h) or LAI data to define a crop density coefficient that was used to directly estimate Kc and Kcb values for a variety of annual and perennial crops in both research and practice. It is opportune to review the A&P method in the context of a variety of studies that have derived Kc and Kcb values from field measured data with simultaneously observed ground cover fc and height. Applications used to test the approach include various tree and vine crops (olive, pear, and lemon orchards and vineyards), vegetable crops (pea, onion and tomato crops), field crops (barley, wheat, maize, sunflower, canola, cotton and soybean crops), as well as a grassland and a Bermudagrass pasture. Comparisons of Kcb values computed with the A &P method produced regression coefficients close to 1.0 and coefficients of determination≥0.90, except for orchards. Results indicate that the A&P approach can produce estimates of potential Kcb, using vegetation characteristics alone, within reasonable or acceptable error, and are useful for refining Kcb for conditions of plant spacing, size and density that differ from standard values. The comparisons provide parameters appropriate to applications for the tested crops. In addition, the A&P approach was applied with remotely sensed fc data for a variety of crops in California using the Satellite Irrigation Management Support (SIMS) framework. Daily SIMS crop ET (ETc-SIMS) produced Kcb values using the FAO56 and A&P approaches. Combination of satellite derived fc and Kcb values with ETo data from Spatial CIMIS (California Irrigation Management Information System) produced ET estimates that were compared with daily actual crop ET derived from energy balance calculations from micrometeorological instrumentation (ETc EB).Results produced coefficients of regression of 1.05 for field crops and 1.08 for woody crops, and R2 values of 0.81 and 0.91, respectively. These values suggest that daily ETc-SIMS -based ET can be accurately estimated within reasonable error and that the A&P approach is appropriate to support that estimation. It is likely that accuracy can be improved via progress in remote sensing determination of fc. Tabulated Kcb results and calculation parameters are presented in a companion paper in this Special Issueinfo:eu-repo/semantics/publishedVersio

    Using the dual-Kc approach to model evapotranspiration of Albarinõ vineyards (Vitis vinifera L. cv. Albarinõ) with consideration of active ground cover

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    Available at SciVerse ScienceDirectThis research aims at testing the dual crop coefficient approach to model the evapotranspiration of the traditional Galician “semi-trellised” vineyard of Vitis vinifera cv. Albari˜no with active ground cover. A separate calculation of soil evaporation, transpiration of the vine crop and transpiration of the active ground cover was conducted. Three irrigation treatments – rain-fed, surface and subsurface drip irrigation – were conducted during three crop seasons (2008–2010). The SIMDualKc model, that performs the soil water balance with the dual Kc approach, was applied for estimating crop evapotranspiration (ETc) by calculating a basal crop coefficient for the vine crop (Kcb full), another for the active ground cover (Kcb cover), which represent the transpiration component of ETc, and a soil evaporation coefficient (Ke). The model was calibrated and validated by comparing model simulated with TDR observed soil water content data. A good fit was obtained showing that modeling was accurate when using the observed fraction of active ground cover, its density and its height, and calculating Kcb cover with field measured data, thus allowing to assess the active ground cover transpiration. As for the vine crop, the best fit was obtained for Kcb full ini = 0.30, Kcb full mid = 1.15 and Kcb full end = 0.9

    Assessing and modelling water use and the partition of evapotranspiration of irrigated hop (Humulus lupulus) and relations of transpiration with hops yield and alpha-acids

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    This study was conducted during three seasons (2012–2014) in an experimental hop yard at Mabegondo,Galicia, NW Spain. The research aimed at calibrating and validating the soil water balance model SIMD-ualKc for Humulus lupulus L. cv. ‘Nugget’. The model computes the soil water balance using the dualKcapproach, thus partitioning crop evapotranspiration (ETc) into crop transpiration, ground covertranspiration and soil evaporation. Calibration and validation were performed using TDR soil watercontent measurements, which produced small root mean square errors (RMSE) ranging from 0.012 to0.015 cm3cm−3. The initial, mid-season and end-season basal crop coefficients (Kcb) that allow com-puting hop transpiration were respectively 0.16, 0.97 and 0.83. The single Kcfor the same crop growthstages, which refers to transpiration and soil evaporation together, were respectively 0.69, 1.02 and 0.85.SIMDualKc provided to estimate water use by the hop yard and the components of the soil water bal-ance, particularly hop transpiration (THop), ground covered transpiration (Tcover) and soil evaporation (Es).THoprepresented 92% of actual evapotranspiration (ETc act) during the mid-season, and Esaveraged 69% ofETc actduring the initial stage. It was observed that Tcoverwas strongly influenced by soil and ground covermanagement. The impacts of water use and THopon hop yield quantity and quality were assessed. A lin-ear regression between hop cone yield and THophas been found, with a high coefficient of determinationr2= 0.92, while the linear regressions of THopwith alpha and beta-acids had regression coefficients notsignificantly different from zero. These results denote appropriate irrigation management with absenceof stresses that could affect yields or the concentration of bitter acidsinfo:eu-repo/semantics/publishedVersio
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