Publications by authors named "Samuel Ortega-Farias"

Accurate assessment of evapotranspiration (ETa) and crop coefficient (Kc) is crucial for optimizing irrigation practices in water-scarce regions. While satellite-based surface energy balance models offer a promising solution, their application to sparse canopies like apple orchards requires specific validation. This study investigated the spatial and temporal dynamics of ETa and Kc in a drip-irrigated 'Pink Lady' apple orchard under Mediterranean conditions over three growing seasons (2012/13, 2013/14, 2014/15).

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The Scholander-type pressure chamber to measure midday stem water potential (MSWP) has been widely used to schedule irrigation in commercial vineyards. However, the limited number of sites that can be evaluated using the pressure chamber makes it difficult to evaluate the spatial variability of vineyard water status. As an alternative, several authors have suggested using the crop water stress index (CWSI) based on low-cost thermal infrared (TIR) sensors to estimate the MSWP.

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The European hazelnut (Corylus avellana) is an important fruit crop cultivated in Chile, with over 17,000 ha planted (46%) in the Maule region, central Chile. During a routine orchard survey in seasons 2020-2021 and 2021-2022, in the Maule region, canker and dieback symptoms were observed in two commercial orchards of European hazelnut cv. Tonda Di Giffoni in San Rafael (8-year-olds) and Linares (15-year-olds), with an incidence between 10% and 36%, respectively, based on external symptoms.

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Atmospheric longwave downward radiation (L) is one of the significant components of net radiation (R), and it drives several essential ecosystem processes. L can be estimated with simple empirical methods using atmospheric emissivity (ε) submodels. In this study, eight global models for ε were evaluated, and the best-performing model was calibrated on a global scale using a parametric instability analysis approach.

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The increase of vineyard's water consumption due to the Global Warming Phenomenon (GWP) has forced the winegrowers to strengthen their irrigation and water stewardship efforts, intended for maintaining this resource's long-term sustainable use. Due to water being a limited resource, implementing the Water Footprint (WF) concept in winegrapes production provides helpful information for sustainable water stewardship. Currently, an automated version of the satellite-based METRIC (Mapping Evapotranspiration with Internalized Calibration) model, the Google Earth Engine Evapotranspiration Flux (EEFlux) platform, has been suggested as an alternative to analyzing the spatial variability of an entire field's water consumption throughout the growing season.

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The midday stem water potential (Ψs) and stomatal conductance (gs) have been traditionally used to monitor the water status of cherry trees ( L.). Due to the complexity of direct measurement, the use of infrared thermography has been proposed as an alternative.

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In the Chilean viticultural industry, Carménère is considered an emblematic cultivar that is cultivated mainly in arid and semi-arid zones. For this reason, it is necessary to use precise irrigation scheduling for improving water use efficiency (WUE), water productivity (WP), yield and wine quality. This study evaluated the effects of three deficit irrigation strategies on gas exchange variables, WUE, WP and yield components in a drip-irrigated Carménère vineyard growing under semi-arid climatic conditions during two consecutive seasons (2011/12 and 2012/13).

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Water stress caused by water scarcity has a negative impact on the wine industry. Several strategies have been implemented for optimizing water application in vineyards. In this regard, midday stem water potential (SWP) and thermal infrared (TIR) imaging for crop water stress index (CWSI) have been used to assess plant water stress on a vine-by-vine basis without considering the spatial variability.

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Water stress, which affects yield and wine quality, is often evaluated using the midday stem water potential (Ψ). However, this measurement is acquired on a per plant basis and does not account for the assessment of vine water status spatial variability. The use of multispectral cameras mounted on unmanned aerial vehicle (UAV) is capable to capture the variability of vine water stress in a whole field scenario.

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An increase in the land area dedicated to super-high density olive orchards has occurred in Chile in recent years. Such modern orchards have high irrigation requirements, and optimizing water use is a priority. Moreover, this region presents low water availability, which makes necessary to establish irrigation strategies to improve water productivity.

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Leaf area index (LAI) is one of the key biophysical variables required for crop modeling. Direct LAI measurements are time consuming and difficult to obtain for experimental and commercial fruit orchards. Devices used to estimate LAI have shown considerable errors when compared to ground-truth or destructive measurements, requiring tedious site-specific calibrations.

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Synopsis of recent research by authors named "Samuel Ortega-Farias"

  • - Recent research by Samuel Ortega-Farias focuses on the optimization of irrigation practices in agricultural settings, particularly in water-scarce regions, by utilizing satellite data and alternative measurement techniques to assess plant water stress and evapotranspiration.
  • - His studies highlight the development of smart, IoT-based solutions for precision irrigation, such as the Crop Water Stress Index (CWSI) derived from low-cost thermal infrared sensors, to enhance vineyard management and water efficiency.
  • - Additionally, Ortega-Farias has investigated the impacts of environmental factors and irrigation strategies on crop health and productivity, with findings relevant to several fruit crops, including apples, wine grapes, and olives, contributing to sustainable agricultural practices in Chile.