GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 Physiological and growth reaction of Shiraz/101-14 Mgt to row orientation and soil water status

Physiological and growth reaction of Shiraz/101-14 Mgt to row orientation and soil water status

Abstract

Context and purpose of the study – Advanced knowledge on grapevine row orientation is required to improve establishment, management and outcomes of vineyards on terroirs with different environmental conditions (climate, soil, topography) and in view of a future change to more extreme climatic conditions. The purpose of this study was to determine the combined effect of row orientation, plant water status and ripeness level on the physiological and viticultural reaction of Shiraz/101-14 Mgt.

Material and methods – The project is carried out in the Breede River Valley, Robertson, South Africa. Shiraz(clone SH 9C)/101-14 Mgt vines were planted during 2003 to a VSP trellis and four row orientations (NS, EW, NE-SW, NW-SE), replicated five times on a flat terroir with uniform clayey loam soil. Vines are spaced to a fixed distance of 1.8 x 2.7 m and pruned to two buds per spur. Since 2014, two water deficit levels are applied to each row orientation treatment, i.e. 75 % and 50 % of the control (reference), the latter receiving the full soil water adjustment per week (based on ET0 values and standard seasonal crop factors). Grapes are harvested at two ripeness levels, i.e. targeting 23 °B and 25 °B.

Results – Total relative evapotranspiration (ETo) fluctuated prominently according to Tmax, RHmin and especially Radiation changes. Photosynthetic activity of the 50 % irrigation treatment tended to be lower across row orientations. Photosynthetic activity of primary leaves decreased during the season. Stem water potential generally decreased with higher water deficit. Clear diurnal and nocturnal profiles of photosynthesis and water potential occurred. The collective physiological response of vines to various environmental factors (light, water availability, temperature, humidity) is complicated and requires understanding at whole plant level. Results on vegetative and reproductive growth characteristics as well as grape composition were variable, but trends are surfacing. Primary and secondary leaf area as well as total leaf area/vine seemed reduced by water deficit treatment. This led to a general increase in primary:secondary leaf area ratio for water deficit treatments. This ratio is an indication of the presence of young leaves in the canopy and is an important measure of canopy capacity to support the obtainment of full grape ripeness. Canopies of control vines thus seemed better suited for supporting complete grape ripening, confirming the importance of judicious vine management to increase the presence of younger leaves. Mass and volume parameters of berries and bunches as well as yields at the two ripeness levels were mostly reduced by water deficit treatments. Differences between the 100% and 75% irrigation treatments were not consistent. Yields generally showed large losses from the first to the second ripeness level.

DOI:

Publication date: September 29, 2023

Issue: GiESCO 2019

Type: Poster

Authors

J.J. HUNTER, C.G. VOLSCHENK

ARC Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch, South Africa

Contact the author

Keywords

row orientation, water deficit, ripeness level, physiology, growth

Tags

GiESCO | GiESCO 2019 | IVES Conference Series

Citation

Related articles…

A predictive model of spatial Eca variability in the vineyard to support the monitoring of plant status

[lwp_divi_breadcrumbs home_text="IVES" use_before_icon="on" before_icon="||divi||400" module_id="publication-ariane" _builder_version="4.19.4" _module_preset="default" module_text_align="center" module_font_size="16px" text_orientation="center"...

Terroir traceability in grapes, musts and wine: results of research on Gewürztraminer and Sauvignon Blanc grape varieties in northern Italy

In the study of terroir, a separate analysis of its many component factors can be of great help in accurately identifying a vineyard’s natural elements that impact wine quality and typicity. This research used a dedicated pluri-disciplinary approach to investigate the ecological characteristics, including geology and geographical features, of 14 vineyards that produce Gewürztraminer and Sauvignon Blanc cultivars in the alpine Alto Adige DOC wine region. Both the geopedological method using Vineyards Geological Identity (VGI) and the new Solar Radiaton Identity (SRI) topoclimatic classification method were used to provide analytical measurements and qualitative/quantitative characterisations. In addition, wide-ranging targeted and untargeted oenological and chemical analyses were carried out on grapes, musts and wines to correlate the soils’ geomineral and physical conditions with the biochemical properties of their fruits and wines. The research identified strong correlations between vineyard geo-identity and wine biofingerprint, confirming a mineral traceability of strontium rubidium ratio and some minerals distinctive to the local geology, such as K, Ca, Ag, Ba and Mn.  The study also discovered that particular geomineral and physical soil conditions of the studied vineyards are related to the different amount of amino acids, primary varietal aromas and polyphenols found in grapes, musts and wines. The research confirmed that winemaking technologies support oenological quality, although in some cases, human practices can overpower certain characteristic elements in wine, erasing the typical imprint left by the vineyards’ natural terroir, which becomes less traceable. Terroir abiotic ecological factors and vineyard identity can be classified in detail using the new VGI and SRI analysis methods to discover interrelationships between geo-pedological and topoclimatic conditions that impact wine quality. These methods are also helpful in identifying which ecological elements are exclusive to a particular vineyard or wine sub-region.

Effect of multi-level and multi-scale spectral data source on vineyard state assessment

Currently, the main goal of agriculture is to promote the resilience of agricultural systems in a sustainable way through the improvement of use efficiency of farm resources, increasing crop yield and quality under climate change conditions. This last is expected to drastically modify plant growth, with possible negative effects, especially in arid and semi-arid regions of Europe on the viticultural sector. In this context, the monitoring of spatial behavior of grapevine during the growing season represents an opportunity to improve the plant management, winegrowers’ incomes, and to preserve the environmental health, but it has additional costs for the farmer. Nowadays, UAS equipped with a VIS-NIR multispectral camera (blue, green, red, red-edge, and NIR) represents a good and relatively cheap solution to assess plant status spatial information (by means of a limited set of spectral vegetation indices), representing important support in precision agriculture management during the growing season. While differences between UAS-based multispectral imagery and point-based spectroscopy are well discussed in the literature, their impact on plant status estimation by vegetation indices is not completely investigated in depth. The aim of this study was to assess the performance level of UAS-based multispectral (5 bands across 450-800nm spectral region with a spatial resolution of 5cm) imagery, reconstructed high-resolution satellite (Sentinel-2A) multispectral imagery (13 bands across 400-2500 nm with spatial resolution of <2 m) through Convolutional Neural Network (CNN) approach, and point-based field spectroscopy (collecting 600 wavelengths across 400-1000 nm spectral region with a surface footprint of 1-2 cm) in a plant status estimation application, and then, using Bayesian regularization artificial neural network for leaf chlorophyll content (LCC) and plant water status (LWP) prediction. The test site is a Greco vineyard of southern Italy, where detailed and precise records on soil and atmosphere systems, in-vivo plant monitoring of eco-physiological parameters have been conducted.

Combining effect of leaf removal and natural shading on grape ripening under two irrigation strategies in Manto negro (Vitis vinifera L.)

The increasingly frequent heat waves during grape ripening pose challenges for high quality wine grape production. Defoliation is a common practice that can improve the control of diseases in bunches, but also it increases the exposure to sunlight. Grapes exposed to solar radiation reach temperatures over the optimum for berry development and maturation. This makes the development of irrigation and canopy management techniques of great importance to maximize yield and grape quality. A field experiment was carried out during 2021 using Manto negro wine grapes to study the effect of applied irrigation and different light exposure levels on grape quality. Two irrigation treatments were imposed based on the frequency and amount of water doses in a four-block experimental vineyard at Bodega Ribas (Mallorca). Three light exposure treatments were randomly applied in each irrigation plot. The light treatments included exposed clusters from pea size, non-exposed clusters, and shaded clusters after softening. Leaf area index and canopy porosity was estimated every 2 weeks. Midday leaf water potential was measured weekly. Additionally, apparent electrical conductivity was measured between rows to estimate the soil water content variability. Light and temperature sensors were installed at the bunch level to quantify the differences in bunch temperature and light intensity among treatments. The effect of irrigation and cluster light exposure on berry weight, TSS, TA, malic acid, tartaric acid, K+, and pH were analysed at 5 moments along grape ripening. During different heat waves, the natural shading technique decreased the maximum bunch temperature around 10 °C respect to the exposed bunches in both irrigation strategies. The combination of defoliation and shading techniques after softening decreased TSS at harvest and affected most of the quality parameters during the last stages of ripening, showing an interesting technique to delay ripening in warm viticulture areas.

Analysis of Cabernet Sauvignon and Aglianico winegrape (V. vinifera L.) responses to different pedo-climatic environments in southern Italy

Water deficit is one of the most important effects of climate change able to affect agricultural sectors. In general, it determines a reduction in biomass production, and for some plants, as in the case of grapevine, it can endorse fruit quality. The monitoring and management of plant water stress in the vineyard