Terroir 2016 banner
IVES 9 IVES Conference Series 9 Impact of defoliation on leaf and berry compounds of Vitis vinifera L. Cv. Riesling investigated using non-destructive methods)

Impact of defoliation on leaf and berry compounds of Vitis vinifera L. Cv. Riesling investigated using non-destructive methods)

Abstract

Climate change has a strong impact on the earlier onset of important phenological stages and plant development in viticulture. Hence, the adaptation of plant management is important to reply to climate related changes on a seasonal or long-term scale. In particular, a change in precipitation and higher temperatures entails the risk negatively impacting on fruit quality. An experiment was conducted where different canopy management strategies were applied to Riesling grapevines (Vitis vinifera L. cv. Riesling) planted in Winkel (Rheingau, Germany). Leaf removal at different canopy positions using various methods (e.g. manual vs. mechanical defoliation practices) led to a reduced photosynthetic active leaf area. Through modifications of the leaf area to fruit weight ratio, the berry ripening can be altered. Leaf removal of the bunch zone impacts fruit parameter and most importantly fruit health. Four different defoliation practices within a VSP trellis system were compared to a non-defoliated control during three growing seasons in an organic treated site: mechanical defoliation above the canopy (MDC); manually defoliation prior to flowering (DpF); defoliation of the bunch zone past flowering: Bunch zone defoliation (BZD) either suction fan plucking (EB490® Binger Seilzug, Germany) and mechanical defoliation or pulsation jetting of compressed air (DmS) (Siegwald®, Germany). Non-destructive measurements using a polyphenolmeter (Multiplex®3, Force-A, Orsay, France) were performed on leaves and berries to estimate the nutrition and ripening stage.

The chlorophyll index showed the lowest values for BZD and highest for control leaves. Additionally, on-the-go measurements were established to determine leaf components achieving vineyard maps in response to nitrogen or chlorophyll index. Furthermore, the data can be used for zoning the vineyard and harvest based on such mapping. When the severity of Botrytis cinerea was compared to control all treatments showed lower disease pressure (BZD -5.3 %, DpF -3.0 % and DmS -2.3 % respectively). Yield differed between -16 % (MDC), -8% DpF, -1 % (DmS) and +1 % (BZD) compared to the control having the highest (1.4 g) and BZD the lowest (1.1 g) single berry weight with a lower bunch compactness in 2014. Defoliation treatments influence the number of cluster per vine, where the lowest were found for DpF plants, accompanied with the lowest yield per single vine. These results help understanding the canopy characteristics and offer an opportunity to adapt the vineyard management strategies to seasonal changes.

DOI:

Publication date: June 23, 2020

Issue: Terroir 2016

Type: Article

Authors

Susanne TITTMANN, Vanessa STOEBER, Manfred STOLL

Geisenheim University, Department of general and organic viticulture, Von – Lade – Str. 1 D-65366 Geisenheim

Contact the author

Keywords

defoliation, non-invasive determination of leaf components, Multiplex, Plasmopara viticola, Vitis vinifera

Tags

IVES Conference Series | Terroir 2016

Citation

Related articles…

Influence of weather and climatic conditions on the viticultural production in Croatia

The research includes an analysis of the impact of weather conditions on phenological development of the vine and grape quality, through monitoring of four experimental cultivars (Chardonnay, Graševina, Merlot and Plavac mali) over two production years. In each experimental vineyard, which were evenly distributed throughout the regions of Slavonia and The Croatian Danube, Croatian Uplands,

Effect of one-year cover crop and arbuscular mycorrhiza inocululation in the microbial soil community of a vineyard

The microbial composition of the soil is an important factor to consider in viticulture, since its influence on the “terroir” and on the organoleptic properties of the wine have been demonstrated. Different agronomic techniques have the potential to modify the composition and functionality of the soil microbial community. Maintaining green covers is known to increase soil microbial diversity. The direct application of inoculum of beneficial microorganisms to the soil has also been used to increase their abundance. However, the environmental conditions of each site seem to have a determining weight in the result of these practices. In this study, we compared the effect on the microbial community of a cover crop with legumes in autumn and the inoculation of grapevines with commercial inoculum bases on Rhizophagus irregularis and Funeliformis mosseae in the previous spring. The study has been carried out in a vineyard in Binissalem, Mallorca, Spain. After applying the treatments, we will analyze the soil microbial communities using the data obtained from Illumina amplification of soil DNA from the 16S and ITS regions to analyze bacteria and fungi community, respectively. In addition, we will record the physicochemical characteristics of the soil at each sampling point. The result showed that agronomic management, in the short term, has less influence than soil characteristics on the composition of the soil microbiome. With these results, we can conclude that in a vineyard, agricultural techniques should focus on improving the characteristics of the soil to improve the biodiversity of the soil microbiota.

Pruned vine biomass exclusion from a clay loam vineyard soil – examining the impact on physical/chemical properties

The wine industry worldwide faces increasing challenges to achieve sustainable levels of carbon emission mitigation. This project seeks to establish the feasibility of harvesting winter pruned vineyard biomass (PVB) for potential use in carbon footprint reduction, through its use as a renewable biofuel for energy production. In order to make this recommendation, technical issues such as the potential environmental impact, chemical composition and fuel suitability, and logistical challenges of harvesting biomass needs to be understood to compare with the results from similar studies. Of particular interest is the role PVB plays as a carbon source in vineyard soils and what effect annual removal might have on soil carbon sequestration. A preliminary trial was established in the Waite Campus vineyard (University of Adelaide) to test current management strategies. Vines are grown in a Eutrophic, Red Dermosol clay loam soil with well managed midrow swards. A comparison was undertaken of mid-row treatments in two 0.25 Ha blocks (Shiraz and Semillon), including annual cultivation for seed bed preparation, the deliberate exclusion of PVB (25 years) and incorporation of PVB (13 years) at an average of 3.4 and 5.5 Mg/Ha-1 for Shiraz and Semillon respectively. In both 0-10cm and 10-30cm soil core sample depths, combined soil carbon % measures in the desired range of 1.80 to 3.50, were not significantly different between treatments or cultivars and yielded an estimated 42 Mg/ha-1 of sequestered soil carbon. Other key physical and chemical measures were likewise not significantly different between treatments. Preliminary results suggest that in a temperate zone vineyard, managed such as the one used in this study, there is no long term negative impact on soil carbon sequestration through removing PVB. This implies that growers could confidently harvest PVB for use in several end fates including as a bio fuel.

Different soil types and relief influence the quality of Merlot grapes in a relatively small area in the Vipava Valley (Slovenia) in relation to the vine water status

Besides location and microclimatic conditions, soil plays an important role in the quality of grapes and wine. Soil properties influence…

The effects of alternative herbicide free cover cropping systems on soil health, vine performance, berry quality and vineyard biodiversity in a climate change scenario in Switzerland

There is an urgent need in viticulture to adopt alternative herbicide-free soil management strategies to mitigate climate change, increase biodiversity, reduce plant protection products and improve soil quality while minimizing detrimental effects on grapevine’s stress tolerance and fruit quality. To propose sustainable solutions, adapted to different pedoclimatic conditions in Switzerland, we developed a multidisciplinary 4-year project, started in 2020. Objectives of the project are to a) evaluate the impact of green covers (spontaneous flora, winter cover crop and permanent ground cover) on environmental and agronomic parameters and b) develop subsequently innovative strategies for different viticultural contexts of Switzerland. The project is divided into 3 phases: 1) diagnosis, 2) on-farm and 3) on-station experiments. Phase 1) consisted in an assessment of 30 commercial vineyards all over Switzerland, where growers already use different herbicide-free soil management strategies. The most promising practices identified in this exploratory phase will be replicated in commercial vineyards across Switzerland (“on-farm”) as well as in a classical randomized block design in an experimental plot (“on-station”). For phase 1), measurements consisted in evaluation of soil status (compaction, structure, roots development), soil microbial diversity (metagenomics), plant diversity and biomass, vine physiology (water stress, vigor, leaf nitrogen) and berry quality (acidity, sugar, available nitrogen). Interestingly, the permanent ground cover resulted in a higher Shannon index thus a higher biodiversity as compared to the other itineraries. The winter cover crop increased vine nitrogen and vigor while deteriorating soil quality, leaving the soil more exposed and compacted likely due to more frequent tillage. The spontaneous flora led to higher berry sugar accumulation, less nitrogen and higher malic acid concentration putatively due to a higher water retention of the flora in a particularly wet vintage. Phases 2) and 3) are required to confirm those tendencies, over the 3 next vintages and different climatic conditions.