Terroir 2020 banner
IVES 9 IVES Conference Series 9 International Terroir Conferences 9 Terroir 2020 9 History and innovation of terroir 9 Usefulness and limits of the crop water stress index obtained from leaf temperature for vine water status monitoring

Usefulness and limits of the crop water stress index obtained from leaf temperature for vine water status monitoring

Abstract

Aims: This work aimed i) to calibrate the accuracy of estimating vineyard water status by crop water stress index (CWSI) compared to stem water potential; ii) to determine the time interval during the day that best correlates to stem water potential and iii) to understand the its usefulness.

Methods and Results: Four levels of irrigation were set up in 2017 on a Cabernet-Sauvignon vineyard grafted to 110R in Morata de Tajuña (Madrid, Spain). The experimental design was a completely randomized four-block design. During two seasons, 2018 and 2019, stem water potential (SWP) and leaf temperature were measured at three time points during the day (8:00; 12.00 and 16:00 solar time) in five dates during 2018 and three dates in 2019. CWSI was calculated based on leaf temperature as the ratio: (Ttreat leaf  Twet)/(Tdry – Twet). Leaf temperature (Ttreat leaf) was measured with an infrared camera model FLIR-E60; Four shaded leaves per treatment were sampled at each time of measurement, for a total of 16 leaves per measurement interval. ANOVA for CWSI and stem water potential was also performed to compare the sensitivity of each parameter to vine water status. All statistical analyses were performed with the Statistix10 package.

Results showed that stem water potential was slightly more sensitive than CWSI to estimate vine water status. Different relationships were found during the season between CWSI and SWP. The determination coefficient was higher at midseason than at the beginning or late in the growing season. The highest R2 were found at noon and during the evening, being no-significant in the morning.

Conclusions: 

Crop Water Stress Index obtained from leaf temperature could be used to estimate plant water status although assuming that it is less sensitive than Stem Water Potential. The index was more accurate in describing the plant water status in midseason than either early or late in the season and better at midday and evening than in the morning.

Significance and Impact of the Study: The study confirms the use of CWSI as a tool to determine vineyard water status and its limitations. Limitations include its effectiveness being confined to midseason and measurements are recommended to be collected from noon onwards. We propose to keep CWSI lower than 0.6 from budbreak until bloom and to move within 0.6 to 0.8 during maturation to ensure SWP is over -1.0MPa (-10 bar) and within -1.0 and -1.2 MPa during ripening.

DOI:

Publication date: March 23, 2021

Issue: Terroir 2020

Type: Video

Authors

G. Camacho-Alonso, P. Baeza*, G. Mendoza, A. Hueso, A.M. Tarquis

Research Centre for the Management of Agricultural and Environmental Risks – CEIGRAM
Universidad Politécnica de Madrid, 28040 Ciudad Universitaria, Madrid, Spain

Contact the author

Keywords

Crop water stress index, stem water potential, thermal images

Tags

IVES Conference Series | Terroir 2020

Citation

Related articles…

First application of an original methodology created to overcome conflicts between stakeholders in an important wine-growing territory: methodology, results, and perspectives in the application of sustainability EME4.1C

Considering the previous research and activities, also, on Sustainability EME4.1C which, as widely known, considers in a harmonious chain all the factors material, immaterial, moral and spiritual related to all aspects environmental, economic, social, existential, relational, ethical, technical and “MetaEthic” indexed 4.1C

Impact of SO2 addition before alcoholic fermentation on the oxidative stability of Chardonnay white wines

Sulfites (SO2) addition during winemaking is a widespread practice worldwide. This addition is realized at different steps of the winemaking due to the antimicrobial and antioxidant capacity of SO2. In a context of understanding white wines oxidative stability, knowledge about the impact of SO2 on the wine molecular diversity, especially compounds involved in the antioxidant capacity of wine, appears to be very important. In recent years, some studies have shown that SO2 can react with a large number of wine compounds resulting in the formation of numerous adducts. The diversity of compounds involved is important including in particular pyruvic acid, 2-keto-glutaric acid, glyceraldehyde, sugar, phenolics compounds but also amino acids or peptides. Moreover Roullier-Gall et al. have shown using FT-ICR-MS analysis that the molecular composition of wines remains impacted by addition of SO2 to the must (0, 4 and 8 g/hL SO2), several years after winemaking. Indeed, wines made from protected must (8g/hL SO2) contain a larger diversity of CHOS and CHONS compounds than wines made from unprotected must (0 g/hL SO2). The study of the impact of glutathione addition on the sensory oxidative stability has further shown that CHOS and CHONS compounds (amino acids, aromatic compounds and peptides) are markers of the antioxidant metabolome of white wines. This suggests that CHOS and CHONS compounds arise from SO2 adducts formation but also from a protecting effect of SO2 on the antioxidant metabolome of white wines.

Adaptability of grapevines to climate change: characterization of phenology and sugar accumulation of 50 varieties, under hot climate conditions

Climate is the major factor influencing the dynamics of the vegetative cycle and can determine the timing of phenological periods. Knowledge of the phenology of varieties, their chronological duration, and thermal requirements, allows not only for the better management of interventions in the vineyard, but also to predict the varieties’ behaviour in a scenario of climate change, giving the wine producer the possibility of selecting the grape varieties that are best adapted to the climatic conditions of a certain terroir. In 2014, Symington Family Estates, Vinhos, established two grape variety libraries in two different places with distinctive climate conditions (Douro Superior, and Cima Corgo), with the commitment of contributing to a deeper agronomic and oenological understanding of some grape varieties, in hot climate conditions. In these research vineyards are represented local varieties that are important in the regional and national viticulture, but also others that have over time been forgotten — as well as five international reference cultivars. From 2017 to 2021, phenological observations have been made three times a week, following a defined protocol, to determine the average dates of budbreak, flowering and veraison. With the climate data of each location, the thermal requirements of each variety and the chronological duration of each phase have been calculated. During maturation, berry samples have been gathered weekly to study the dynamics of sugar accumulation, between other parameters. The data was analysed applying phenological and sugar accumulation models available in literature. The results obtained show significant differences between the varieties over several parameters, from the chronological duration and thermal requirements to complete the various stages of development, to the differences between the two locations, confirming the influence of the climate on phenology and the stages of maturation, in these specific conditions.

Key phenolic compounds in the pulp of new red-fleshed table grape hybrids: anthocyanins and flavonols 

The cultivated area of table grapes worldwide has experienced a paramount increase over the last two decades. In this current scenario, traditional varieties are being replaced by new cultivars that prioritize a profitable and sustainable agriculture, while satisfying consumer demands. It is widely recognized that wine varieties, especially those with red berry flesh, are renowned for their high antioxidant capacity and phenolic compounds, which promote health. Recently, this topic has also gained significance in table grape breeding programs.

Effetti del cambiamento climatico europeo sulle epoche di vendemmia in Abruzzo

I dati termo-pluviometrici del periodo 1971-2009 registrati da alcune stazioni della regione Abruzzo sono stati analizzati adottando alcuni semplici indici climatici e bioclimatici. E’ stato valutato il verificarsi di cambiamenti climatici così come le loro ripercussioni sulle date di inizio vendemmia.