César Acevedo-Opazo

Universidad de Talca · Center for Irrigation and Agroclimatology Research (CITRA)

Grapevine phenology and total soluble solids (TSS) accumulation are important information to plan agricultural operation in the vineyards over the season. The study aims at identifying the main environmental factors and related high spatial auxiliary information that could be used to define within-field zones of phenology and TSS accumulation. An e...

Background: Recently, antitranspirant or radiation-reflective products have been studied in several crops to mitigate the negative effects of global warming in Mediterranean climates. Nevertheless, to our knowledge, there is a scarce availability of information studying their effects on blueberries and much less from applications of sunscreens elab...

(1) Background: Currently, some ampelographic methods are developing in order to identify grapevine varieties. For this purpose, morpho-colorimetric parameters in leaves have been analyzed by digital imagen analysis, but some environmental conditions may affect their determinations. (2) Methods: A research study was conducted to characterize leaf m...

La fisiología del cultivar y la calidad de la uva se ven afectadas por la elección del portainjerto. Existe poca información disponible sobre los efectos del uso de los portainjertos en la composición volátil del vino, más aún cuando si estos se comparan con vides sin injertar. Por lo tanto, el objetivo de este ensayo de campo fue estudiar la influ...

The aim of this study is to propose an empirical spatial model to estimate the spatial variability of grapevine phenology at the within-field scale. This spatial model allows the characterization of the spatial variability of a given variable of the fields through a single measurement performed in the field (reference site) and a combination of sit...

This paper proposes a methodology to improve grape yield sampling and yield estimation of the current season by using historical yield data. This approach is based on the conjoint use of (i) historical yield data all over the study field and (ii) several yield measurements collected at specific sites within the field during the current season. The...

In the near future, stomatal behaviour will be crucial to counteract conditions arising from climate change. Grapevine varieties are classified as either isohydric or anisohydric, depending on the sensitivity of stomata to water deficit and on their water potential homeostasis. However, the great variability observed in different studies indicates...

In the near future, stomatal behaviour will be crucial to counteract conditions arising from climate change. Grapevine varieties are classified as either isohydric or anisohydric, depending on the sensitivity of sto-mata to water deficit and on their water potential homeostasis. However, the great variability observed in different studies indicates...

Monitorings of weather and soil water content have been used to estimate water consumption and irrigation needs of poplar plantations. However, these methods do not consider the real water conditions of the plant. Recent research has shown that measurements that integrate diverse physiological responses and dasometric measurements, can increase pre...

Aims: This work focuses on the study of the intra- and inter-annual Temporal Stability of Within-Field Variability (TSWFV) of Total Soluble Solids (TSS) as an estimate of grape maturity. Methods and results: The experiment was carried out between 2009 and 2015 in four fields located in the Maule Valley, Chile, under irrigated conditions. Each fiel...

Con la finalidad de optimizar el manejo hídrico a nivel de campo de dos híbridos comerciales de álamo (Populus x canadensis "I-214" y Populus x canadensis "I-488"), se llevó a cabo un ensayo durante las temporadas 2015-16 y 2016-17 en la “Compañía Agrícola y Forestal el Álamo” en un rodal comercial de 6,56 hectáreas. En este dispositivo se evaluaro...

Botrytis cinerea causes one of the most serious diseases in grapevines namely Botrytis Bunch Rot (BBR). A classification of different grapevine cultivars (cvs.) according to their susceptibility to B. cinerea is an essential management indicator in Integrated Pest Management. Although such classifications are available, they are based mostly on pro...

Early disease risk indicators (pectin and tannin content in berry skins) were evaluated at berry pea-size stage to investigate the potential susceptibility of berries to BBR at harvest.

The main strategy to control powdery mildew (Erysiphe necator [Schw.] Burr.) in Chilean vineyards is largely based on periodic fungicide spraying (up to 18 applications per season), which may lead to many environmental and human health risks. This study aimed to evaluate the effectiveness of three control strategies for powdery mildew: i) a Decisio...

The susceptibility of winegrape cultivars to Botrytis cinerea is a debated topic, and the available classifications are based on professional experience rather than on experimental data. The main aim of this study was to compare and classify the susceptibility of several winegrape cultivars to B. cinerea and its relation to fruit maturity under two...

The aim of this work is to validate an empirical approach to estimate spatial variability of the total soluble solids (TSS) of grapevine at the within field scale. Estimation of TSS involves a spatial model calibrated with historical TSS data. The novelty of the approach is to provide a collaboration between historical data of TSS (calibrated model...

The aim of this work is to calibrate and validate an empirical approach to predict the date of occurrence of the grapevine phenology (budburst, flowering and veraison) temporally and spatially at the within-field scale. It is based on the collaboration between a classical model of phenology based on climate data and a spatial model calibrated with...

This paper proposes a methodology aiming at using historical yield data to improve yield sampling and yield estimation. The sampling method is based on a collaboration between historical data (at least three years) and yield measurements of the year performed on some sites within the field. It assumes a temporal stability of within field yield spat...

Background: The primary strategy to control powdery mildew in Chilean vineyards involves periodic fungicide spraying, which may lead to many environmental and human health risks. This study aimed to implement and evaluate the effectiveness and economic feasibility of a novel Decision Support Strategy (DSS) to limit the number of treatments against...

Estudio del intercambio gaseoso en Chardonnay, Merlot, Pinot Noir y Sauvignon Blanc

The aim of this work is to validate an empirical approach to estimate spatial variability of the total soluble solids (TSS) of grapevine at the within field scale. Estimation of TSS involves a spatial model calibrated with historical TSS data. The novelty of the approach is to provide a collaboration between historical data of TSS (calibrated model...

Knowledge and monitoring of the grapevine phenology during the season are important requirements for characterization of productive regions, climate change studies and planning of various production activities at the vine field scale. This work aims at studying the spatial variability of grapevine phenology at the within field scale. It was conduct...

Spatial variability of the hydric state of the vine and its relationship with the maturity of the berry at the level of the viticultural quarter

Cet article présente un modèle spatial empirique permettant de produire une estimation de la phénologie de la vigne sur la base d’une observation de référence et d’une base de données historique. Le modèle a été étalonné avec les données d’une parcelle cv Cabernet Sauvignon (1,56 ha) situé à Talca, Chili. Les résultats montrent que le modèle permet...

For drip-irrigated olive orchards, plant water status monitoring is an important tool for irrigation management practices, as it determines final fruit and oil yield. However, plant water status monitoring using plant physiological measurements, such as plant water potential and stomatal conductance (gs) imposes a challenge because the selection of...

Aims: Long exposure to high temperatures or UV-radiation may induce negative effects on vine physiology and grape composition. Here, the effects of two methods to moderate radiation and temperature in the fruit zone of a Cabernet Sauvignon vineyard were evaluated against a control. Methods and results: The treatments assessed were: (a) periodical s...

The aim of this work was to study the intra and inter-annual temporal stability of the within-field variability (TSWFV) of total soluble solids (TSS) as an estimate of grape maturity. The experiment was carried out between 2009 and 2014, on four fields all of them located in the Maule Valley, Chile, under irrigated conditions. A regular sampling gr...

A study was carried out to evaluate the leaf gas exchange relations and water-use efficiency (WUE) of ungrafted Carmènére (Vitis vinifera L.) grapevines growing under field conditions and different levels of water stress. Stomatal conductance (gs, transpiration (E), net C02 assimilation (AN.) and stem water potential (Ψs) were measured at midday in...

Abstract Yield estimation is an important task for any vine grower to organize logistical operations such as harvest, wine storing and also sell it on the market. Some researches as well as results from vine growers in the central zone of Chile have reported errors about 15 to 40% in yield estimation using classical field manual sampling. Consequen...

Yield estimation is an important task for any vine grower to organize logistical operations such as harvest, wine storing and also sell it on the market. Some researches as well as results from vine growers in the central zone of Chile have reported errors about 15 to 40% in yield estimation using classical field manual sampling. Consequently, ther...

The dominant strategy followed by vine-growers in Chile to control powdery mildew (Erysiphe necator) involves schedule phytosanitary applications resulting between 9 to 18 fungicide sprays depending on the grape cultivar and the geographical area, mainly with sulphur applications. This large application of chemicals generates many environmental and...

La podredumbre gris causada por el hongo Botrytis cinerea es una enfermedad presente en todos los viñedos del mundo, la cual requiere de mucha vigilancia por parte de los viticultores debido a que los daños ocasionados por esta pueden afectar negativamente la calidad de los vinos. En Chile, para su control en general los viticultores realizan un us...

Stomatal conductance (gs) is a plant variable normally used in models that estimate plant water requirements, and furthermore can be used as an integrative tool to monitoring the level of plant water restriction. However, gs requires skills and heavy devices, which drastically limit the number of replications either in space or in time. Moreover, d...

A study was conducted in order to characterize the effect of regulated deficit irrigation on gas exchange of four isohydrics and anisohydrics grapevines cultivars (Pinot Noir, Sauvignon Blanc, Chardonnay and Merlot) to reduce the use of water irrigation. The experiment was conducted on a vineyard located in the Panguilemo Experimental Station belon...

Isohydric and anisohydric behavior

En vides vinífera el control de oídio (Erysiphe necator) se realiza mediante un uso intensivo de fungicidas (12 a 15 aplicaciones por temporada), principalmente de carácter preventivo, siendo el azufre el más utilizado. Sin embargo poco se conoce sobre el efecto de éste sobre los artrópodos asociados al viñedo. Así durante la temporada 2012-2013 se...

Gestión hídrica del arándano en la Región del Maule, mediante la aplicación de un sistema integral de información Araya-Alman, M. 1, López-Olivari, R. 1, Soto, N. 1, Morales, R. 1, Acevedo, C. 1, Ortega-Farías, S. 1 1Centro de Investigación y Transferencia en Riego y Agroclimatología (CITRA), Facultad de Agronomía, Universidad de Talca, Talca, Chi...

p style="text-align: justify;"> Aims : Climate-based indices exist for viticulture, particularly for modelling phenological events, but not for vine water status. In this work, climatic variables are linked to the temporal evolution of the water status of the vine Methods and Results : Within-season time-series of predawn leaf water potential from...

p style="text-align: justify;"> Aim : Recent work has identified strong intra-field relationships of predawn leaf water potential ( Ψ _PD) between paired sites. This study investigates if these relationships exist at the inter-field level when soil types between fields are constant or different in a vineyard in Southern France. Method and...

ESTUDIO ESPACIALIZADO DE DOS ESTRATEGIAS DE CONTROL DE OIDIO EN UN CUARTEL VITICOLA cv. CABERNET SAUVIGNON. 1Araya-Alman, M., 2Verdugo-Vásquez, N., 3Avalo-Henríquez, A., 4Valdés-Gómez, H., 5Acevedo-Opazo, C. (1, 2, 3, 4,5)Universidad de Talca, Facultad de Ciencias Agrarias, CITRA. Casilla 747, Talca. E-mail: miaraya@utalca.cl Se realizó un estud...

This paper establishes and tests a model to extrapolate vine water status spatially across a vineyard block. The proposed spatial model extrapolates predawn leaf water potential (PLWP), measured at a reference location, to other unsampled locations using a linear combination of spatial ancillary information sources (AIS) and the reference measureme...

Precision irrigation in grapevines could be achieved using physiologically based irrigation scheduling methods. This paper describes an investigation on the effects of three midday stem water potential (midday ΨS) thresholds, imposed from post-setting, over water use, vegetative growth, grape quality and yield of grapevines cv. Cabernet Sauvignon....

The goal of this study is to propose a model that allows for spatial extrapolation of the vine water status over a whole field from a single reference site. The precision of the model was tested using data of spatial plant water status from a commercial vineyard block located in the Languedoc-Roussillon region, France. Observations of plant water s...

The goal of this study was to test the feasibility of extrapolating a single vine water status measurement to several locations using ancillary information with a high-spatial resolution. An experiment to identify and test the model was carried out over a commercial 'Syrah' field located in the Languedoc-Roussillon Region, France, during the 2003 a...

The tendency for more frequent events of El Niño!Southern Oscillation Event (ENSO) since the late 1970's has been questioned about how anticipate the water management strategies of the crops. Niño events are characterised by high rain and moderated temperatures, whereas Niña events produce the opposite effects. In this context, a research was carri...

The tendency for more frequent events of El Niño-Southern Oscillation Event (ENSO) since the late 1970's has been questioned about how anticipate the water management strategies of the crops. Niño events are characterised by high rain and moderated temperatures, whereas Niña events produce the opposite effects. In this context, a research was carri...

Background and Aims: Water stress in grapevines is directly linked to grape quality. Differential vine water management should therefore be strongly linked to the water stress in the vine. To do this, an understanding of the dominant drivers and indicators of vine water status are needed from a sub-block to whole vineyard level. This understanding...

Abstract. Vine canopy reflectance data are typically obtained from aircraft or satellite images in the visible and near infrared (NIR) regions of the spectrum and subsequently transformed into vegetation indices such as the normalized difference vegetation index (NDVI). This index is related to photosynthetically active biomass and can be used to...

L'évolution de l'état hydrique de la vigne tout au long de son cycle de croissance annuel a un effet direct sur la composition du raisin et sur la qualité de la récolte. Cet effet s'explique par l'influence de l'état hydrique de la plante sur la croissance végétative, la croissance des fruits, le rendement, le microclimat de la canopée et le métabo...

The goal of this study was to test the usefulness of high-spatial resolution information provided by airborne imagery and soil electrical properties to define plant water restriction zones within-vineyards. The main contribution of this is to propose a study on a large area representing the regions' vineyard diversity (different age, different vari...

p style="text-align: justify;"> Aims : Plant water status monitoring during the vineyard growth cycle constitutes a basic parameter for both harvest quality and vineyard management. Unfortunately, the plant water status measurement requires skills and heavy devices which drastically limit the number of repetitions either in space or in time. Moreov...

Abstract. In 2007 different observations were carried out on 11 vineyards. 3 georeferenced sampling points were defined per vineyard and several measurements were made at veraison such as NDVI, ELA (Exposed Leaf Area), LAI (Leaf Area Index), PLWP (predawn leaf water potential) as well as before harvest : number and average weight of bunches, berry...

Une étude a comparé les valeurs de NDVI (Normalized Difference Vegetation Index) obtenues par imagerie aérienne à la véraison avec des mesures sur vigne à la même date (Surface foliaire exposée, LAI (Leaf Area Index), potentiel foliaire de base) et avant récolte (nombre et poids moyen de grappes, poids des baies, teneurs en sucres, acidité totale,...

ABSTRACT The wine industry in Australia is facing an unprecedented challenge to maintain wine production and quality in the current drought. Climate change predictions indicate that such events will become more frequent and will occur against a backdrop of increasing temperature and evaporative demand, and quantitative and qualitative deterioration...

The Shuttleworth and Wallace model (SW) was evaluated to estimate latent heat flux above a drip-irrigated Cabernet Sauvignon vineyard, located in the Pencahue Valley, Region del Maule, Chile (35°22¢ LS; 71°47¢ LW; 150 m above sea level). The performance of the WS model (LE ws) was evaluated against the eddy-covariance method (LE ed) on a 30 min tim...

Abstract This work aims at proposing a first approach towards a spatial model of the vine water status. The goal is to test whether or not it is possible to predict the plant water status using such a model at several unsampled locations and at different time considering only one reference measurement for each prediction date. An experiment was car...

Abstract This paper reports a study to test the potential of high spatial resolution information provided by airborne imagery to define time stable plant water restriction zones within vineyard scale. An experiment was carried out on 9 fields located in Languedoc- Roussillon region, France during 2006. On each field, different zones were defined ac...