GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 Soil proximal sensing provides direction in delineating plant water status of ‘crimson seedless’ (Vitis vinifera L.) vineyards

Soil proximal sensing provides direction in delineating plant water status of ‘crimson seedless’ (Vitis vinifera L.) vineyards

Abstract

Context and Purpose of the Study – ‘Crimson Seedless’ (Vitis vinifera L.) is a late-ripening, red seedless table grape cultivar with inadequate anthocyanin accumulation and less than ideal berry size issues. It was necessary to understand the natural variations in the vineyard as well as the application of proximal sensing to monitor, and estimate these variations to get desirable attributes in this cultivar. The objective of this study was to use of proximal and remote sensing tools, specifically soil electrical conductivity (EC), canopy normalized difference vegetation index (NDVI), and carbon isotope discrimination in a precision agriculture context, to assess the water status variability, and determine the effect of inferred variability on skin anthocyanin and flavonol concentration at harvest.

Material and Methods – A ‘Crimson Seedless’ (V. vinifera L.) grafted on to ‘Freedom’ (27% vinifera hybrid) rootstock vineyard was studied for two years with contrasting precipitation amounts. Soil electrical conductivity (EC) was proximally sensed with electromagnetic induction and canopy reflectance was sensed remotely to calculate normalized difference vegetation index (NDVI). Random and equi-distant (30 m × 30 m) sampling grids were utilized in 2016 and 2017 to ground truth proximally sensed data. Grape primary metabolites, including total soluble solids, total acidity, isotopic discrimination of berry sugars (δ13C) and pH were measured, and secondary metabolites were characterized with a C18 reversed-phase HPLC.

Results – Soil EC was related to the variation of season-long plant water status in 2016 (Deep EC: r = -0.71; Surface EC: r = -0.53). There was not a significant relationship between NDVI and plant water status in either year.  The vineyard was separated and delineated into two water status zones based on stem water potential (􀀁stem) in each year, and the water status between two zones were significantly and consistently different. The juice pH showed significant differences between two zones. The δ13C was directly and significantly related to 􀀁stem integrals and the differences between the two water status zones were confirmed by either method in 2016. There were no differences in total anthocyanins in 2016. However, anthocyanin derivatives were greater in the low water status zone in the following year. Flavonol amounts were not consistently different between the two zones in either year. Our results indicated deep soil EC, season-long water status or δ13C can be used interchangeably to spatialize and cluster management zones in commercial table grape vineyards.

DOI:

Publication date: June 18, 2020

Issue: GiESCO 2019

Type: Poster

Authors

Runze YU1, Luca BRILLANTE2, Johann MARTÍNEZ-LÜSCHER1, S. Kaan KURTURAL1

(1) Dept. of Viticulture and Enology, University of California, Davis, CA, 95616, USA
(2) Dept. of Viticulture and Enology, California State University, Fresno, CA, 93704, USA

Contact the author

Keywords

Crimson Seedless, table grapes, anthocyanins, flavonoids, water status, electrical conductivity, normalized difference vegetation index (NDVI), spatial variability, viticulture

Tags

GiESCO | GiESCO 2019 | IVES Conference Series

Citation

Related articles…

A spatial explicit inventory of EU wine protected designation of origin to support decision making in a changing climate

Winemaking areas recognized as protected designations of origin (PDOs) shape important economic, environmental and cultural values that are tied to closely defined geographic locations. To preserve wine products and wine-growing practices adopted in different PDOs these areas are strictly regulated by legal specifications. However, quality viticulture is increasingly under pressure from climate change, which is altering the local conditions of many winegrowing areas. Therefore, maintaining traditional wine products will require the adoption of tailored adaptation strategies, including possible changes in the legal regulation of protected wines. To this end, it is necessary to have a comprehensive knowledge on PDOs including their extension, products and allowed practices. While there have been efforts to build databases that summarize the characteristics for individual wine PDO areas and to quantify the related effects of climate change, much information is still included only in the official documentation of the EU geographical indication register and has never been collected in a comprehensive manner. With this study we aim at filling this gap by building a spatial inventory of European wine PDOs that supports decision making in viticulture in the context of climate change. To map and characterize European wine PDOs, we analysed their legal documents and extracted relevant information useful for climate change adaptation. The output consists of a comprehensive geographical dataset that identifies the boundaries of all 1200 European wine PDOs at unprecedented spatial resolution and includes a set of legally binding regulations, such as authorized vine varieties, maximum yields and planting density. The inventory will allow researchers to analyse the impacts of climate change on European wine PDOs and support decision makers in developing tailored adaptation strategies. This includes, among others, the evaluation of new vineyard site selection, the expansion of cultivated varieties or the authorization of irrigation in vineyards.

Modeling island and coastal vineyards potential in the context of climate change

Climate change impacts regional and local climates, which in turn affects the world’s wine regions. In the short term, these modifications rises issues about maintaining quality and style of wine, and in a longer term about the suitability of grape varieties and the sustainability of traditional wine regions. Thus, adaptation to climate change represents a major challenge for viticulture. In this context, island and coastal vineyards could become coveted areas due to their specific climatic conditions. In regions subject to warming, the proximity of the sea can moderate extremes temperatures, which could be an advantage for wine. However, coastal and island areas are particular prized spaces and subject to multiple pressures that make the establishment or extension of viticulture complex.
In this perspective, it seems relevant to assess the potentialities of coastal and island areas for viticulture. This contribution will present a spatial optimization model that tends to characterize most suitable agroclimatic patterns in historical or emerging vineyards according to different scenarios. Thanks to an in-depth bibliography a global inventory of coastal and insular vineyards on a worldwide scale has been realized. Relevant criteria have been identified to describe the specificities of these vineyards. They are used as input data in the optimization process, which will optimize some objectives and spatial aspects. According to a predefined scenario, the objectives are set in three main categories associated with climatic characteristics, vineyards characteristics and management strategies. At the end of this optimization process, a series of maps presents the different spatial configurations that maximize the scenario objectives.

Exploring resilience and competitiveness of wine estates in Languedoc-Roussillon in the recent past: a multi-level perspective

The Languedoc-Roussillon wineries are facing a decline in wine yields particularly PGI yields due to many factors. Climate change is just ones, but is expected to increase in the future. There is also structurally a large heterogeneity of yield profiles among terroirs, varieties and strategies. This work investigates the link between yield, competitiveness and resilience to explore how resilient winegrowers have been in the recent past. To this end two approaches have been combined; (i) an accountancy database analysis at estate scale and (ii) municipality level competitiveness analysis. A new resilience indicator that characterizes the capacity of an estate to absorb yield variation is also defined. The FADN database between 2000 and 2018 of ex-Languedoc-Roussillon (France) and other data are used to analyse the current situation and the past evolution of competitiveness and resilience by type of estate (type of farm: PGI and/or PDO & type of commercialization: bulk and/or bottles). The net margin, which defines competitiveness, is not correlated to yield for all types but depends on the type of commercialization and the level of specialisation. The resilience indicator shows that the net margin of estates specialized in PGI is particularly sensitive to yield declines. We also show that price evolutions seem to compensate the effect of yield losses for the majority of types. Municipality scale analysis shows the links between local pedoclimate, yield, commercialization strategies and price. Overlapping a PDO with a PGI does not always increase a municipality’s PGI competitiveness. It is difficult to make links between causes and effects due to the complexity of the wine production system. Production diversification may be a solution. Resorting to the two level of analysis helps resolving the data gap that is necessary to explore the links between yield and economic performance of the wine estates in the long term.

The use of rootstock as a lever in the face of climate change and dieback of vineyard

As viticulture faces challenges such as climate change or vineyard dieback, the choice of the variety and rootstock becomes more and more crucial. To study rootstock levers in the Bordeaux region, a parcel of Cabernet Sauvignon (CS) was planted with four rootstocks in 2014. Twenty repetitions of each of the following four rootstocks were set up: 101-14 MGt, Nemadex AB, 420A MGt and Gravesac. The number of bunches, yields and pruning weights of the vine shoots were measured individually on 240 vines from 2017 to 2021. Since 2020, nitrogen status assessed by assimilable nitrogen level, hydric status assessed by δ13C and berry maturity were measured on 80 samples taken from 20 repetitions of the four rootstocks. A lower yield was measured for CS grafted onto Nemadex AB due to the lower number of bunches and the lower weight of berries. The differences between the other three rootstocks are small, but CS grafted onto 420A MGt was the most productive. The CS grafted onto Nemadex AB had the lowest pruning weight while 101-14 MGt had the highest. In 2020, δ13C showed a more moderate water stress with 101-14 MGt and 420A MGt than with Nemadex AB. Surprisingly, the Gravesac was under more stress than the 101-14 MGt. The nitrogen status in the berries was better for Nemadex AB but this was perhaps due to the significantly lower weight of the berries.Rootstock 101-14 MGt attained the highest accumulation of sugars in the berries while 420A MGt allows to preserve higher acidity. The parcel is still young which may explain some of the results. These measures must therefore be continued over the next several years to fully assess the effects of these rootstocks on the development of the vines and the quality of the production under new climatic conditions.

Influence of a spontaneous cover crop on the vineyard and soil erosion under Mediterranean climate

Sixty five % of the agricultural area of the Basque Country located in the DO Ca Rioja corresponds to vineyards. More than 40% of it has an average slope greater than 10%, which makes it sensitive to erosive processes. Furthermore, it is foreseeable that extreme weather events (storms, hail, extreme heat and cold, etc.) will be favored due to climate change. Cover cropping can mitigate this risk, and therefore the objective of this work is to evaluate the impact that a vegetable cover has on the agronomic behavior of the vineyard, the quality of the grape and soil erosion. For this, a trial has been carried out with a Graciano variety vineyard with a slope between 10% -20% during the years 2020 and 2021. Conventional tillage management in the area has been compared (4-6 passes per year of tillage machinery) versus spontaneous vegetation cover management in the vineyard. This implies not tilling and allowing the grass of the land to colonize the range between the lines of vines, controlling their height through 1-3 mowing passes per year, always trying to affect the surface of the land as little as possible. The vegetative growth, yield and quality of the grape and wine was measured. Furthermore, erosion has been measured using Gerlasch boxes. The yield was lower in the second year of the trial in the cover crop treatment, but erosion was significantly reduced.