GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 GiESCO 2019 9 Sensitivity of vis‐nir spectral indices to detect nitrogen deficiency and canopy function in cv. Barbera (Vitis vinifera L.) Grapevines

Sensitivity of vis‐nir spectral indices to detect nitrogen deficiency and canopy function in cv. Barbera (Vitis vinifera L.) Grapevines

Abstract

Context and purpose of the study ‐ Precision nutrient management in viticulture can be addressed on the basis of a spatial characterization of within‐vineyard vine nutritional status derived from proximal or remote spectral observations. However, a key challenge is the discrimination between mineral deficiencies and water stress related issues, often coexisting under low vigor conditions. In addition several mineral disorders are associated to a decrease in chlorophyll concentration in leaves resulting in a wide array of symptoms classified as chlorosis. Despite clearly associated to their origin, visible symptoms appear too late for supporting an efficient mineral management; thus, non‐destructive early detection of either asymptomatic excess or deficient status become a challenging task of precision viticulture. This work evaluates the Vis‐NIR reflectance spectra and the sensitivity of the derived‐spectral indices to detect nitrogen deficiency in grapevines.

Material and methods ‐ Well N‐fertilized vs. unfertilized vines were compared over two seasons (2016 and 2017) on Vitis vinifera L. cv. Barbera potted vines. For each treatment, 24 leaves from eight representative vines were tagged in order to collect, at different phenological stages, contact Vis‐NIR spectra and perform physiological measurements. The performance of several spectral vegetation indices sensitive to different biophysical (i.e. chlorophyll and carotenoids content, leaf area index) and physiological parameters (light use efficiency) was measured by means of a sensitivity (signal to noise ratio) analysis. Leaf greenness index was monitored with a handheld chlorophyll meter SPAD 502 whilst single‐leaf gas exchanges were assessed by using a handheld analyzer. Multispectral analysis was associated to a rigorous ground‐truthing as it concerns shoot growth, yield, fruit composition and pruning weight.

Results – In both years the differential fertilization increased leaf N concentration of N+ vines at veraison. Vine performance varied according to plant vigor and nutritional status. N+ increased canopy growth, vine productivity, and bunch compactness whilst N0 enhanced the proportion of shot berries and reduced titratable acidity and malate in juice. N deficiency resulted in lower SPAD readings and assimilation rates as compared to well N‐fertilized vines. N0 vs N+ contact Vis‐NIR spectra differed in Green and Red‐edge regions with faster responses on basal leaves. Data were associated to a different sensitivity of Vis‐NIR spectral indices specially when based on the Red‐edge bands showing higher efficiency in detecting leaf N concentration since early stages of canopy growth.

DOI:

Publication date: June 22, 2020

Issue: GiESCO 2019

Type: Article

Authors

Matteo GATTI (1,2), Alessandra GARAVANI (1,2), Alberto VERCESI (1), Cecilia SQUERI (1), Michele CROCI (1,2), Ferdinando CALEGARI (2), Massimo VINCINI (2), Stefano PONI (1,2)

(1) DIPROVES Università Cattolica del Sacro Cuore, Via E. Parmense 84, I-29122 Piacenza, Italy
(2) CRAST Università Cattolica del Sacro Cuore, Via E. Parmense 84, I-29122 Piacenza, Italy

Contact the author

Keywords

Mineral nutrition, Visual symptoms, Leaf age, Assimilation, Yield components, Phenotyping

Tags

GiESCO 2019 | IVES Conference Series

Citation

Related articles…

Analysis of some environmental factors and cultural practices that affect the production and quality of the Manto Negro, Callet and Prensal Blanc varieties

45 non irrigated vineyards distributed in the DO (Denomination) Pla i Llevant de Mallorca and the DO Binissalem Mallorca were used to investigate the characteristics of production and quality and their relationships certain environmental factors and cultural practices. The grape varieties investigated are autochthonous to the island of Mallorca, Manto Negro and Callet as red and Prensal Blanc as white. All plants were measured for four consecutive years in the main production and quality parameters. Among the environmental factors, the type of soil has been studied, more specifically its water retention capacity, the planting density, the age of the vineyard and the level of viral infection. The presence or absence of virus seems to have no effect on any component studied in the varieties studied. For the white variety Prensal Blanc age is negatively correlated with production and the number of bunches, nevertheless it does not cause any effect on the required quality parameters. However, for the red varieties Callet and Manto Negro, the age of the plantation is the variable that best correlates with the quality parameters, therefore the old vines should be the object of preservation by the viticulturists and winemakers in order to guarantee its contribution to the quality of the wines made with these varieties.

austrianvineyards.com: online viewer of all designations of Austrian wine

To digitally record and present all the origins of Austrian wines in the same perfect and clear way was the motivation for the Austrian Wine Marketing Board (Austrian Wine) to start with the project in 2018. In June 2021 the results were presented to the public in an online viewer showing all the designations of Austrian wine, available at https://austrianvineyards.com in a largely barrier-free manner. The online viewer provides tailored individual maps fitted to the respective zoom level. The smallest unit of wine-origins in Austria is called Ried and is displayed in a plot-specific manner highlighting areas under vine. Information on the Ried include administrative district, winegrowing municipality, cadastral municipality, large collective vineyard site, specific winegrowing region, generic winegrowing region, winegrowing area and, in many cases, an illustrative picture. Complementary data on the size, elevation (minimum-maximum), orientation (in 8 sectors plus flat) and gradient (minimum, maximum, average) are based on the area under vine according to the EU’s Integrated Administration and Control System. Additional information covers climate data. The diagrams are taken from the monthly breakdown of data in the annals of the Central Institute for Meteorology and Geodynamics, Austria provide a display of values for air temperature, precipitation, and sunshine hours for the reference year and the long-term average. Seasonal aggregated data on temperature, precipitation, and sunshine hours complete the display. Short descriptions with emphasis on geology and soil, field name in historical maps, etymology of the denomination, and main planted variety complements the available information for the main designations in the online viewer. These descriptions are compiled by winegrowers, geologists, historians, and journalists. All the information and data can be extracted to a pdf-file. Printed vineyard maps are also available. Missing content regarding wine origins in Styria will be completed in winter 2021/22.

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.

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"...

Low-cost sensors as a support tool to monitor soil-plant heat exchanges in a Mediterranean vineyard

Mediterranean viticulture is increasingly exposed to more frequent extreme conditions such as heat waves. These extreme events co-occur with low soil water content, high air vapor pressure deficit and high solar radiant energy fluxes and result in leaf and berry sunburn, lower yield, and berry quality, which is a major constraint for the sustainability of the sector. Grape growers must find ways to proper and effectively manage heat waves and extreme canopy and berry temperatures. Irrigation to keep soil moisture levels and enable adequate plant turgor, and convective and evaporative cooling emerged as a key tool to overcome this major challenge. The effects of irrigation on soil and plant water status are easily quantifiable but the impact of irrigation on soil and canopy temperature and on heat convection from soil to cluster zone remain less characterized. Therefore, a more detailed quantification of vineyard heat fluxes is highly relevant to better understand and implement strategies to limit the effects of extreme weather events on grapevine leaf and berry physiology and vineyards performance. Low-cost sensor technologies emerge as an opportunity to improve monitoring and support decision making in viticulture. However, validation of low-cost sensors is mandatory for practical applicability. A two-year study was carried in a vineyard in Alentejo, south of Portugal, using low-cost thermal cameras (FLIR One, 80×60 pixels and FLIR C5, 160×120 pixels, 8-14 µm, FLIR systems, USA) and pocket thermohygrometers (Extech RHT30, EXTECH instruments, USA) to monitor grapevine and soil temperatures. Preliminary results show that low-cost cameras can detect severe water stress and support the evaluation of vertical canopy temperature variability, providing information on soil surface temperature. All these thermal parameters can be relevant for soil and crop management and be used in decision support systems.