Terroir 2020 banner
IVES 9 IVES Conference Series 9 Variety specific thresholds for plant-based indicators of vine nitrogen status

Variety specific thresholds for plant-based indicators of vine nitrogen status

Abstract

Aim: Several plant-based indicators of vine N status are reported in the literature. Among these, yeast assimilable nitrogen in grape must (YAN) and total N concentration of petiole and leaf blades are considered to be reliable indicators and so is the chlorophyll index, measured with a device called N-tester. The N-tester index is used to measure the intensity of the green colour of the leaf blade, and therefore to estimate its chlorophyll content. The aim of this study is to measure the nitrogen content of various grapevine organs (petiole, leaf blade, grape must) and the intensity of the green colour of leaf blades, in order to establish variety specific thresholds for the interpretation of plant-based indicators of vine nitrogen status.

Methods and Results: To study the varietal effect on indicators of vine N status, the latter were measured during 4 years on 35 grapevine varieties grafted on the same rootstock and planted with replicates in an experimental vineyard in the Pessac-Léognan appellation in Bordeaux. The results of N-tester measurements carried out at mid-flowering and mid-véraison were compared with the nitrogen content of leaf blades and petioles at véraison and the concentration of yeast assimilable nitrogen (YAN) in the must at maturity. 

Conclusions: 

Strong varietal and year effects were observed for all indicators. Leaf blade nitrogen showed the lowest variability and YAN the highest. The N-Tester values recorded at mid-flowering were more consistent than those at mid-véraison.

Significance and Impact of the Study: Among the nutrients required by the vine, nitrogen is one of the most important. It is an essential factor in vegetative and reproductive development. Vine nitrogen status influences grape composition and wine quality. In addition, a low concentration of assimilable nitrogen in the must causes fermentation problems because N is one of the essential substrates for yeast growth. Vine N status depends on environmental factors (soil and climate) but can be managed through fertilisation and vineyard floor maintenance. Hence, plant-based indicators for vine nitrogen status are of utmost importance to optimize management practices for obtaining high wine quality and sustainable yields. The data generated by this experiment can help to take into account varietal specific responses to nitrogen availability when establishing thresholds for plant-based indicators of vine N-status. An example is provided for N-tester values at mid-flowering.

DOI:

Publication date: March 17, 2021

Issue: Terroir 2020

Type: Video

Authors

Agnès Destrac-Irvine, Elisa Marguerit, Mark Gowdy, Bruno Suter, Julien Fort, Francesco Rinaudi and Cornelis van Leeuwen 

EGFV, Bordeaux Sciences Agro, INRAE, Univ. Bordeaux ISVV, F-33882 Villenave d’Ornon, France

Contact the author

Keywords

Vine nitrogen status, petioles, leaf blades, must

Tags

IVES Conference Series | Terroir 2020

Citation

Related articles…

Future projections for chilling and heat forcing for European vineyards

Aims: The aims of this study were: (1) to compute recent-past thermal conditions over European vineyards, using state-of-the art bioclimatic indices: chilling portions and growing degree hours; (2) to compute future changes of these thermal conditions using a large ensemble of high-resolution climate models.

Quantification of polysaccharides of variety Pomaces of the D.O.Ca Rioja

Pomace is one of the main residues generated by the wine industry and represents an environmental problem. Currently, there is a growing interest in the revaluation of these products because different bioactive compounds can be obtained from them, such as polyphenols, grape seed oils and polysaccharides. Red grape pomace can be an important source of polysaccharides, but they are currently little studied and even less with viable and environmental extraction processes (green extraction), such as flash extraction. The residual amount of the fraction rich in pectin (residual pulp) and component rich in hemicellulose in the pomace and the strength of association of the pectin with the cellulose-xyloglucan network depend on the degree of extractability of the polysaccharides in red winemaking and on the winemaking conditions.

Brown Marmorated Stink Bug taint in grape must and wine: time evolution of trans-2-decenal

The brown marmorated stink bug (BMSB, Halyomorpha halys Stal) is an invasive pentatomid native to eastern Asia that is spreading rapidly worldwide, notably through human-mediated activities. Globally, it was reported in the USA, Canada, Italy, Hungary, and other European countries. BMSB has a broad host range that includes over 170 plants, many of agricultural importance, including various fruit, vegetables, row crops, and ornamentals. When present in the vineyard, the pest can affect yield and quality by directly feeding on berries resulting in fruit collapse and necrosis. Additional damage occurs when BMSB are carried into the winery within the grape clusters. The presence of BMSB during wine processing can affect juice and wine quality through the release of volatile compounds produced as a stress response. The major secretes compounds are tridecane and trans-2-decenal. Tridecane is an odorless compound and its effect on wine quality is currently unknown. Trans-2-decenal is an unsaturated aldehyde considered to be the main component of BMSB taint with strong green, coriander, and musty-like aromas. Its threshold value in wine was estimated at about 5 µg/L.

Under-vine management effects on grapevine vegetative growth, gas exchange and rhizosphere microbial diversity

The use of cover crops under the vines might be an alternative to the use of herbicides or tillage, improving grapevine quality and soil characteristics. The aim of this research was to study the implications of different management strategies of the soil under the vines (herbicide, cultivation or cover crops) on grapevine growth, water and nutritional status, gas exchange parameters and belowground microbial communities.
The experimental design consisted in 4 treatments applied on 35L-potted Tempranillo vegetative grapevines with 10 replicates each grown in an open-top greenhouse in 2022 and 2023. Treatments included two cover crop species (Trifolium fragiferum and Bromus repens), herbicide (glyphosate al 36%) and an untreated control.

Development of breeding of PIWI varieties in the Czech Republic

Context and purpose of the study. The Czech Republic is one of the most important grape growers of PIWI varieties in the Europe, as the total area planted with PIWI varieties is almost 1000 ha.