Terroir 2020 banner
IVES 9 IVES Conference Series 9 Effect of two contrasting soils on grape and wine sensory characteristics in Shiraz

Effect of two contrasting soils on grape and wine sensory characteristics in Shiraz

Abstract

Aims: Berry composition and wine sensory characteristics reflect the origin of grape production and seasonal climatic conditions. The aim of this study was to compare berry and wine sensory characteristics from two contrasting soil types where the vineyard climate, geography, topography, vine and management factors were not different.

Methods and Results: Two adjoining blocks of Shiraz with similar vine age (+/-1 year), identical clone (1654), row orientation (NW, SE) and cordon height were selected for this study. All irrigation, spray and midrow management treatments were identical. Both sites have soils that are texture contrast or duplex brown chromosols. The main distinguishing feature between the two sites being the presence of 10% to 50% ironstone gravel, mainly in the bleached topsoil “E” (or A2) horizon for the “Ironstone” block which is in contrast to the “Sand over clay” block. 

Berry sensory attributes were evaluated using the accepted method of berry sensory assessment (BSA). The method allows for the identification and quantification of berry sensory attributes against standard sensory references by a trained panel. The evaluation of wine sensory attributes was performed using a quantitative descriptive analysis (QDA). Both methods were performed to assess sensory differences in grapes and wine from the two soil types. Berries from the “Ironstone” soil had more intense green/grassy flavour, a higher perception of acidity and greater astringency. This was in contrast to berry samples from the sand over clay soil, which were described as having more intense dried fruit/jammy flavour, a higher perceived sweetness and an elevated toasted flavour. Wines made from fruit from the “Ironstone” soil were found to have more intense red fruit characters, tannin quality and astringency in contrast to the dark fruit, higher colour intensity and confectionary characteristics of the wines made from fruit from “Sand over clay” soils.  Fifty-six soil mineral elements were analysed from each soil horizon, leaf blades, must and wine samples. Results obtained from inductively couple plasma atomic emission spectroscopy (ICP-OES) analysis identified elements some of which were unique to each soil type and some which were in higher concentrations. The differences in the two soils elemental status was translated to leaves, berries and wine from those soils. 

Conclusions: 

Differences were observed in berry and wine sensory characteristics when comparing the fruit harvested from two contrasting soils in close proximity. Soils displayed very similar physical characteristics. Both soils were observed to be texture contrast or duplex brown chromosols. They shared common features of sandy or loamy topsoils (“A” horizons) over brown light clay (LC) to light medium (LMC) “B” horizons with or without highly weathered sandstone in the subsoil or “C” horizon. There was no soil carbonate present at any site and topsoil pH was neutral (pH 6.5-7.5) and decreased slightly to 6.0 in the “B” and “C” horizons.  Root zones, both predicted and observed were not significantly different.

Slight differences were observed between the soils with measures of readily available water (RAW), topsoil depth and a unique layer of gravel in the ironstone soil all of which have been associated in previous research with water movement and plant water availability in soils. Analysis of the chemical composition and concentration of soils, vines, grapes, musts and wines demonstrated distinct differences in the chemical characteristics between the two soil sites. This study was able to investigate soils with different soil chemistries and sensory characteristics for berries and wine in isolation from other known influences including viticultural, environmental, many other soil, and winemaking factors. 

The application of elements to vines in a controlled environment in future work may provide a link between soil chemistry and grape and wine sensory attributes. 

Significance and Impact of the Study: Soil elemental composition is a contentious aspect of terroir especially in relation to the relative importance afforded to climate and soil physical characteristics in previous research. This trial was able to isolate soil for analysis to observe unique elemental compositions in varying concentrations in relation to differences in berry and wine sensory outcomes. The mechanisms by which soil elements might influence sensory outcomes of wines is not widely understood and future research could lead to soils and wines being paired for desired sensory outcomes.

DOI:

Publication date: March 17, 2021

Issue: Terroir 2020

Type: Video

Authors

Anthony Hoare*, Michael McLaughlin, Cassandra Collins

School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Urrbrae, SA, Australia

Contact the author

Keywords

Elemental composition, fruit quality, wine quality, soil chemistry

Tags

IVES Conference Series | Terroir 2020

Citation

Related articles…

Projected changes in vine phenology of two varieties with different thermal requirements cultivated in La Mancha DO (Spain) under climate change scenarios

The aim of this work was to analyze the phenology variability of Tempranillo and Chardonnay cultivars, related to the climatic characteristics in La Mancha Designation of Origin, and their potential changes under climate change scenarios. Phenological dates referred to budbreak, flowering, veraison and harvest were analyzed for the period 2000-2019. The weather conditions at daily time scale, recorded during the same period, were also evaluated. The thermal requirements to reach each of these phenological stages were calculated and expressed as the GDD accumulated from DOY=60. Changes in phenology were projected by 2050 and 2070 taking into account those values and the projected temperatures and precipitation, simulated under two Representative Concentration Pathway (RCP) scenarios –RCP4.5 and RCP8.5– using an ensemble of models. The average phenological dates during the period under study were, April 16th ± 6.6 days and April 5th ± 6.0 days for budbreak, May 31st ± 6.0 days and May 27th ± 5.3 days for flowering, July 26th ± 5.6 days and July 25th ± 5.8 days for veraison, and Ago 23rd ± 10.8 days and Ago 17th ± 9.0 days for harvest, respectively, for Tempranillo and Chardonnay. The projected changes in temperature imply an average change in the maximum growing season (April-August) temperatures of 1.2 and 1.9°C by 2050, and 1.6 and 2.6°C by 2070, under the RCP4.5 and RCP8.5 scenarios, respectively. A reduction in precipitation is predicted, which vary between 15% for 2050 under RCP4.5 scenario and up to 30% by 2070 under RCP8.5. The advance of the phenological dates for 2050, could be of 6, 7, 7, and 8 days for Tempranillo and 4, 6, 6 and 9 days for Chardonnay, respectively for budbreak, flowering, veraison and harvest under the RCP4.5 scenario. Under the RCP8.5 emission scenario, the advance could be up to 30% higher.

Biodiversity in the vineyard agroecosystem: exploring systemic approaches

Biodiversity conservation and restoration are essential for guarantee the provision of ecosystem services associated to vineyard agroecosystem such as climate regulation trough carbon sequestration and control of pests and diseases. Most of published research dealing with the complexity of the vineyard agroecosystems emphasizes the necessity of innovative approaches, including the integration of information at different temporal and spatial scales and development of systemic analysis based on modelling. A biodiversity survey was conducted in the Franciacorta wine-growing area (Lombardy, Italy), one of the most important Italian wine-growing regions for sparkling wine production, considering a portion of the territory of 112 ha. The area was divided into several Environmental Units (EUs), defined as a whole vineyard or portion of vineyard homogenous in terms of four agronomic characteristics: planting year, planting density, cultivar, and training system. In each EU a set of compartments was identified and characterised by specific variables. The compartments are meteorology, morphology (altitude, slope, aspect, row orientation, and solar irradiance), ecological infrastructures and management. The landscape surrounding EU was also characterised in terms of land-use in a buffer zone of 500 m. For each component a specific methodology was identified and applied. Different statistical approaches were used to evaluate the method to integrate the information related to different compartments within the EU and related to the buffer zone. These approaches were also preliminarily evaluated for their ability to describe the contribution of biodiversity and landscape components to ecosystem services. This methodological exploration provides useful indication for the development of a fully systemic approach to structural and functional biodiversity in vineyard agroecosystems, contributing to promote a multifunctional perspective for the all wine-growing sector.

VINIoT: Precision viticulture service for SMEs based on IoT sensors network

The main innovation in the VINIoT service is the joint use of two technologies that are currently used separately: vineyard monitoring using multispectral imaging and deployed terrain sensors. One part of the system is based on the development of artificial intelligence algorithms that are feed on the images of the multispectral camera and IoT sensors, high-level information on water stress, grape ripening status and the presence of diseases. In order to obtain algorithms to determine the state of ripening of the grapes and avoid losing information due to the diversity of the grape berries, it was decided to work along the first year 2020 at berry scale in the laboratory, during the second year at the cluster scale and on the last year at plot scale. Different varieties of white and red grapes were used; in the case of Galicia we worked with the white grape variety Treixadura and the red variety Mencía. During the 2020 and 2021 campaigns, multispectral images were taken in the visible and infrared range of: 1) sets of 100 grapes classifying them by means of densimetric baths, 2) individual bunches. The images taken with the laboratory analysis of the ripening stage were correlated. Technological maturity, pH, probable degree, malic acid content, tartaric acid content and parameters for assessing phenolic maturity, IPT, anthocyanin content were determined. It has been calculated for each single image the mean value of each spectral band (only taking into account the pixels of interest) and a correlation study of these values with laboratory data has been carried out. These studies are still provisional and it will be necessary to continue with them, jointly with the training of the machine learning algorithms. Processed data will allow to determine the sensitivity of the multispectral images and select bands of interest in maturation.

Spatiotemporal patterns of chemical attributes in Vitis vinifera L. cv. Cabernet Sauvignon vineyards in Central California

Spatial variability of vine productivity in winegrapes is important to characterise as both yield and quality are relevant for the production of different wine styles and products. The objectives were to understand how patterns of variability of Cabernet Sauvignon fruit composition changed over time and space, how these patterns could be characterised with indirect measurements, and how spatial patterns of the variation in fruit compositional attributes can aid in improving management. Prior to the 2017 vintage, 125 data vines were distributed across each of four vineyards in the Lodi American Viticultural Area (AVA) of California. Each data vine was sampled at commercial harvest in 2017, 2018, and 2019. Yield components and fruit composition were measured at harvest for each data vine, and maps of yield and fruit composition were produced for eight ‘objective measures of fruit quality’: total anthocyanins, polymeric tannins, quercetin glycosides, malic acid, yeast assimilable nitrogen, β-damascenone, C6 alcohols and aldehydes, and 3-isobutyl-2-methoxypyrazine. Patterns of variation in anthocyanins and phenolic compounds were found to be most stable over time. Given this relative stability, management decisions focused on fruit quality could be based on zonal descriptions of anthocyanins or phenolics to increase profitability in some vineyards. In each vineyard, dormant season pruning weights and soil cores were collected at each location, elevation and soil apparent electrical conductivity surveys were completed, and remotely sensed imagery was captured by fixed wing aircraft and two satellite platforms at major phenological stages. The data collected were used to develop relationships among biophysical data, soil, imagery, and fruit composition. The standardised and aggregated samples from four vineyards over three seasons were included in the estimation of ‘common variograms’ to assess how this technique could aid growers in producing geostatistically rigorous maps of fruit composition variability without cumbersome, single season sampling efforts.

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.