GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 GiESCO 2019 9 Is early defoliation a sustainable management practice for mediterranean vineyards? Case studies at the portuguese lisbon winegrowing region

Is early defoliation a sustainable management practice for mediterranean vineyards? Case studies at the portuguese lisbon winegrowing region

Abstract

Context and purpose of the study ‐ Recently early defoliation (ED) has been tested in several high‐ yielding grapevine varieties and sites aiming at reducing cluster compactness and hence, regulating yield and susceptibility to botrytis bunch rot infection. The reported results have been generally positive, encouraging growers to use this canopy management technique as an alternative for replacing the conventional time‐consuming cluster thinning and, simultaneously, as a sustainable practice to reduce the use of fungicides. However, ED increases berry sunburn risks and/or can induce carry‐over effects on vigor and node fruitfulness as shown in the two case studies reported in this work.

Material and methods ‐ Two ED experiments were set up at a commercial vineyard located in the Lisbon winegrowing region with the varieties Aragonez, syn. Tempranillo (2013‐2015) and Semillon (2018). In both experiments the ED treatment was compared with the non‐defoliated (ND; control) using a randomized complete block design with 4 replicates per treatment. The ED treatment consisted of the removal of 5‐6 basal leaves and any laterals at pre‐flowering. Vegetative (leaf area and pruning weight) and reproductive components (%fruit‐set, cluster number, cluster weight, yield) and berry composition were assessed.

Results ‐ In the Aragonez experiment total leaf area at harvest and pruning weight were significantly lower in ED vines. The ED treatment presented also a significantly lower fruit‐set, berry weight, cluster weight and compactness, as well as yield as compared to the control. In the third season ED presented a significantly lower cluster number indicating a negative carry‐over effect on bud initiation induced by the early source limitation. Regarding berry composition, ED showed a higher Brix and a lower titratable acidity than the control but no significant differences were detected on skin anthocyanins. The incidence and severity of botrytis bunch rot infection was significantly higher in the control treatment. In the Semillon experiment the ED treatment showed also a significantly lower leaf area, fruit‐set, berry weight, cluster weight, cluster compactness and yield. No significant differences were detected on berry composition except for Brix where ED showed a significantly higher value. Despite the low pressure of botrytis bunch rot infection the control presented the significantly highest incidence and severity. An heat event occurred during the first week of August induced a severe and significantly higher berry sunburn in the ED treatment. Our results show that pre‐bloom defoliation is a canopy management practice with high potential for regulating grape yield and with benefits for grape health.However, in Mediterranean climates, where water and heat stress can inhibit leaf area compensation, the negative effects observed either on berry sunburn and on node fruitfulness recommends to use this practice with care or even avoid it. 

DOI:

Publication date: June 19, 2020

Issue: GIESCO 2019

Type: Article

Authors

Carlos M. LOPES (1), Marta VENDEIRO, Ricardo EGIPTO (1), Olfa ZARROUK (2), M. Manuela CHAVES (2)

(1) LEAF, Instituto Superior de Agronomia, Universidade de Lisboa, Portugal
(2) Instituto de Tecnologia Química e Biológica, Oeiras, Portugal

Contact the author

Keywords

early defoliation, fruit‐set, grapevine, botrytis rot, berry sunburn

Tags

GiESCO 2019 | IVES Conference Series

Citation

Related articles…

Study of the content of amino acids and biogenic amines in sparkling red wines

The production of red sparkling wines is lower in Spain in comparison with the winemaking of white or rosé sparkling wines. In red sparkling wine processing it is essential to obtain suitable base wines that should have moderate alcohol content, high acidity, good color values, an adequate mouth-feel and a sweet tannin. Grapes for sparkling wine production have to be harvested at low maturity stages, with lower alcohol contents and higher acidities, which will that the phenolic maturity of the grapes is also low, showing green tannins. This paper analyses different treatments in order to minimize these inconveniences: cold maceration-prefermentation and delestage to elaborate the grapes with lower maturity, must nanofiltration, and the partial osmosis of the wines made from grapes with an adequate maturity degree.

Measurement of redox potential as a new analytical winegrowing tool

Excell laboratory has initiated the development of an analytical method based on electrochemistry to evaluate the ability of wines to undergo or resist to oxidative phenomena. Electrochemistry is a powerful tool to probe reactions involving electron transfers and offers possibility of real-time measurements. In that context, the laboratory has implemented electrochemical analysis to assess oxidation state of different wine matrices but also in order to evaluate oxidative or reduced character of leaf and soil. Initially, our laboratory focused on dosage of compounds involved in responses of plant stresses and we were also interested in microbiological activity of soils. These analyses were compared with the measurement of redox potential (Eh) and pH which are two fundamental variables involved in the modulation of plant metabolism. Indeed, the variation of redox states of the plant reflects its biological activity but also its capacity to absorb nutriments. The Eh-pH conditions mainly determine metabolic processes involved in soil and leaf and our goal is to determine if this combined analytical approach will be sufficiently precise to detect biological evolutions (plant health, parasitic attack…).

Monitoring grapevine water status using Landsat 8 images: a two-year case study in a Merlot vineyard

Viticulture needs for spatial and temporal information are increasing to improve vineyard management, especially concerning water efficiency. Remote sensing, particularly from satellites, can be a powerful tool to assess vineyard characteristics such as vigor or water status in space-time. In this study, we use Landsat 8, an American Earth observation satellite with six bands from the visible (VIS) to the Short-Wave Infrared (SWIR) domains with 30m spatial resolution and two thermal bands with 100m spatial resolution.

Assessment of environmental sustainability of wine growing activity in France

To meet the demand of assessment tool of vine growers and their advisers we adapted to the vine production the INDIGO® method to developed initially for arable farming.

Application de l’Analyse du Cycle de Vie (ACV) à un domaine viticole

Since 1980, Château de l’Éclair has belonged to SICAREX Beaujolais and has been involved in experimentation for the Beaujolais vineyards. However, it is a commercial estate with profitability and quality constraints, which means that it has to meet the growing environmental expectations of consumers. Given the number of practices claimed to be environment-friendly, it is sometimes difficult to prioritize actions.