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Grapevine is one of the most important perennial fruit crops worldwide. Historically, vineyards were compatible with soil conservation practices and multitrophic biodiversity, but vineyards are now generally eroded and biologically impoverished, making them more susceptible to pests and diseases. However, the idiosyncrasy of the wine sector places wine growers in a unique position to lead the adoption of a range of sustainable management strategies and, thus, to pioneer a wider transformation of the agricultural sector. In this article, we provide an overview of nature-based management strategies that may be used for the regeneration of the functioning and biodiversity of vineyards and that may also lead to improved plant nutrition, grape berry quality and the suppression of pathogens and pests. These strategies include the use of microbial and nonmicrobial biostimulants, fertilization with organic amendments as well as foliar fertilization with nature-based products, the use of cover crops and the reintegration of livestock in vineyards, especially sheep. We will also pay special attention to the implementation of circular economy in the vineyard in relation to the previously mentioned management strategies and will also discuss the importance of considering all these aspects from a holistic and integrative perspective, rather than taking them into account as single factors. Assuming the integral role of soils in the functioning of agroecosystems, soils will be considered transversally across all sections. Finally, we will argue that the time is now ripe for innovation from the public and private sectors to contribute to the sustainable management of vineyards while maintaining, or even improving, the profit margin for farmers and winemakers.

Urea is frequently used as a fertiliser in agriculture. In addition, foliar applications of urea in the vineyard have improved the nitrogen composition of the grapes and could improve their quality. There are many studies about the effect of foliar application of urea on red grapevines, but there are no works about the effect of timing application and three doses of urea on nitrogen composition in Tempranillo Blanco grapes. Consequently, the objective of this study was to determine the influence of three doses of urea, applied at two different phenological stages (pre-veraison and veraison), on the nitrogen composition of Tempranillo Blanco grapes during two consecutive years. The results showed that, in general, the foliar application of urea, at both phenological stages, increased the amino acids concentration in Tempranillo Blanco grapes, without modified oenology parameters and yield. A different behaviour was observed between the three doses applied at pre-veraison and veraison, because 6 kg N ha−1 treatment, applied at pre-veraison, and 9 kg N ha−1 treatment, applied at veraison, improved the concentration of amino acids during the two years. In addition, amino acids concentrations were mainly affected by year and treatment factors. Consequently, foliar application could be considered a good strategy to increase amino acids concentration in Tempranillo Blanco grapes that are poor in these compounds.

Grapevine is one of the most important perennial fruit crops worldwide. Historically, vineyards were compatible with soil conservation practices and multitrophic biodiversity, but vineyards are now generally eroded and biologically impoverished, making them more susceptible to pests and diseases. However, the idiosyncrasy of the wine sector places wine growers in a unique position to lead the adoption of a range of sustainable management strategies and, thus, to pioneer a wider transformation of the agricultural sector. In this article, we provide an overview of nature-based management strategies that may be used for the regeneration of the functioning and biodiversity of vineyards and that may also lead to improved plant nutrition, grape berry quality and the suppression of pathogens and pests. These strategies include the use of microbial and nonmicrobial biostimulants, fertilization with organic amendments as well as foliar fertilization with nature-based products, the use of cover crops and the reintegration of livestock in vineyards, especially sheep. We will also pay special attention to the implementation of circular economy in the vineyard in relation to the previously mentioned management strategies and will also discuss the importance of considering all these aspects from a holistic and integrative perspective, rather than taking them into account as single factors. Assuming the integral role of soils in the functioning of agroecosystems, soils will be considered transversally across all sections. Finally, we will argue that the time is now ripe for innovation from the public and private sectors to contribute to the sustainable management of vineyards while maintaining, or even improving, the profit margin for farmers and winemakers.

Non-Saccharomyces yeasts, particularly Metschnikowia pulcherrima, are considered alternatives to SO2 in winemaking, combating specific microorganisms. The sensory profile of the wine is contingent upon the type of yeast, the fermentation conditions, and the concentration and mode of application with Saccharomyces cerevisiae strains (whether pure or used in mixed/sequential co-fermentation). This study assessed the aroma in red wines produced with S. cerevisiae (Sc) and M. pulcherrima (Mp, non-Sc), incorporating variations in the method of addition and the inclusion or exclusion of SO2. The enological parameters of the wines were slightly affected. Volatile compounds were analysed in the wines through gas chromatography–mass spectrometry (GC-MS) at three moments: at the end of malolactic fermentation (MLF) and after 6 and 9 months of bottle ageing. Sequential fermentation of Sc and Mp reduced the concentration of most identified alcohols and acids, which is favourable, as these compounds can yield undesirable aromas at high concentrations. Regardless of the yeast mixture and Mp dose, a majority of the acetate esters and ethyl esters were quantified at concentrations above their perception thresholds, thus enhancing the sensory quality of the wines. Sensory analysis of wines showed generally positive evaluations. Using non-Saccharomyces as an alternative to SO2 improves the aromatic profile of wines.

The knowledge of volatile compounds concentration in grape berries is very valuable information for the winemaker, since these compounds are strongly involved in the final wine quality, and in consumer acceptance. In addition, it would allow to set the harvest date according to aromatic maturity, to classify grape berries according to their quality and to make wines with different characteristics, among other implications. However, so far, there are no tools that allow the volatile composition to be measured directly on intact berries, either in the vineyard or in the winery.

Polysaccharides are the main group of macromolecules in wines. Climate change is a major problem for viticulturists as it leads to the production of unbalanced grapes. This is attributed to a mismatch between the technological maturity and phenolic maturity of grapes, which can negatively impact the production of high quality wines. To mitigate this effect, biostimulants can be applied to grapevines. For the first time in the literature, this work studied the foliar application of methyl jasmonate plus urea (MeJ + Ur) on the vineyard and its effect on the monosaccharide and polysaccharide composition of Tempranillo grapes and wines over two consecutive seasons. To achieve this, the extraction and precipitation of polysaccharides was conducted, and the identification and quantitation of monosaccharides was performed via GC–MS. The effect of MeJ + Ur foliar treatment in both the grapes and wines was season-dependent. The MeJ + Ur treatment had a slight impact on the monosaccharide composition of the grapes and also demonstrated a small effect on the wines. Multifactor and discriminant analysis revealed that the season had a greater influence on the monosaccharide and polysaccharide composition of grapes and wines compared to the influence of MeJ + Ur treatment. Interestingly, the MeJ + Ur-treated wines exhibited a higher sensory evaluation than the control wines in the second vintage. To gain further insights into the effect of MeJ + Ur foliar application on the monosaccharide and polysaccharide composition of grapes and wines, further investigations should be conducted.

Foliar nutrient sprays are broadly used in commercial agriculture. To date, the application of Ca and Si has been little explored in vineyard production but may lead to positive responses at various levels. Therefore, the aim of this work was to evaluate the effect of supplying single or combined calcium (Ca, 120 mM) and silicon (Si, 120 mM) sprays in Tempranillo grape composition. Foliar treatment with Ca + Si foliar enhanced all families of aromatic compounds, whereas single Ca and Si sprays induced lower effects. Regarding phenolic compounds, all foliar treatments led to minor effects. However, all three foliar Ca and Si treatments increased the total grape amino acid content. Consequently, the application of combined Ca and Si sprays to a vineyard is recommended as a tool for improving grape quality.

Pulsed electric fields effect was studied on the physico-chemical and general phenolic composition as colour characteristics and stilbene content in must and wine. For this purpose, a continuous pulsed electric fields equipment was used to treat three red grape varieties of DOCa Rioja. Graciano, Tempranillo and Grenache wines from these grapes were elaborated with different maceration times, 2 days in the untreated sample (control) and the PEF-treated sample (PEF), and normal maceration time in another untreated sample (control-NM). Parameters as colour intensity, anthocyanin content, total polyphenol index and tannin content showed no differences between the PEF sample with 2 days of maceration and the control-NM sample, except in the case of Tempranillo wines. Total stilbenes, trans-resveratrol and trans-piceid of Graciano wines elaborated from PEF samples showed a higher concentration than the control wines. Alternatively, PEF wines and control-NM wines showed no differences between them. Tempranillo variety wines presented no differences between the three types of samples. In the Grenache variety, only trans-piceid levels showed differences between control and PEF wines. Moreover, relationship between must and wine characteristics was evaluated and compared between different samples. The trend lines obtained for the CI, TPI and AC parameters for samples of Graciano, Tempranillo and Garnacha indicate that the initial content of compounds extracted significantly affected the days of maceration necessary to obtain the appropriate wine. The results obtained increase the knowledge of pulsed electric fields as a technology available for use in the winery to elaborate red wines with reduced maceration time.

Spectral instruments can be useful for the rapid assessment of chemical compounds in different targets, and their use have been already reported for the modeling of grape composition comparing two spectral ranges. Still, with the increased easiness of acquiring data with several sensors, it would be valuable to explore spectral fusion techniques for the modeling with deep learning, seeking to obtain improved performance. Therefore, the objective of this work was to develop multi-sensor spectral fusion approaches for the deep learning modeling of grape composition. From 128 grape samples, two spectra per sample were acquired from two different ranges using two sensors (visible and shortwave near infrared, 570–1000 nm; and wider NIR 1100–2100 nm). From each sample, 15 grape nitrogen compounds were analyzed by wet chemistry. Three different data fusion approaches are defined using neural networks and deep learning, testing several ways of structuring and merging the input spectra. Statistical analyses supported that (i) the proposed deep learning fusion architectures performed better than single spectral range models, and (ii) neural networks have better modeling capabilities than partial least squares in spectral fusion. The results demonstrate the potential of deep learning for spectral data fusion in grape nitrogen composition regression, and potentially other traits in food and agriculture spectroscopy.

Polysaccharides in wine play important roles in the stabilization and in the sensory properties of wines. Elicitor application constitutes an interesting field of research since it is indirectly involved in the accumulation in grape cell walls of molecules like callose, lignin, phenolic compounds and glycoproteins. Currently, biomimetic calcium phosphate (ACP) nanoparticles are successfully used in viticulture for the controlled delivery of bioactive molecules, such as elicitors. The aim of this study was to compare the effect of the application of two different elicitors on both grape and wine of Tempranillo polysaccharide composition. Methyl jasmonate (MeJ) and nanoparticles doped with MeJ were applied to the canopy at veraison and one week later in two vintages. In the grape extracts, the foliar treatments did not increase the content of monosaccharides or that of the main pectin families; therefore, the elicitors did not reinforce the cell walls of the Tempranillo grape. The extractability and solubility of the pectic families of the grape cell walls into the wine depended on the type of family and the climate of the vintages.

Tools to address the mismatch between technological and phenolic maturity of grapes are needed. Application of elicitors could be an effective alternative. This work compares the effect of the application of methyl jasmonate (MeJ) in conventional form and, as a novelty, in the form of MeJ-doped nanoparticles (ACP-MeJ) on the phenolic composition of Tempranillo grapes. Results showed that, regardless of season, both treatments increased the grape total phenols content. In 2019, most of the anthocyanins, and to a lesser extent the flavanols, increased with the application of MeJ, and several hydroxycinnamic acids increased in the grapes treated with ACP-MeJ, with dose 10 times lower than those of the MeJ conventional. In 2020, anthocyanins were not affected by the treatments, but total flavanols, flavonols, hydroxybenzoic acid, and stilbenes increased after ACP-MeJ application. Thus, foliar application of ACP-MeJ could serve to increase grape phenolic composition, reducing maturity decoupling and the environmental impact.

Background and goals The aim of this work was to study, for the first time, the influence of foliar application of methyl jasmonate (MeJ) and methyl jasmo-nate plus urea (MeJ+Ur) on Tempranillo grape phenolic composition over two seasons. Methods and key findings This work examined grape phenolic compounds usi ng hi gh-per f or mance l i qui d chromatography-diode array detection. In 2019, both treatments increased the total anthocyanins, but the MeJ+Ur treatment had a stronger effect than the MeJ treatment. MeJ foliar application decreased total flavonols, total flavanols, and total hydroxycinnamic acids in the grapes, while MeJ+Ur significantly decreased total flavonols, but did not affect total flavanol s or hydroxyci nnami c aci ds. Neither of the foliar treatments affected total stilbenes. However, in 2020, the effect of treatments was different: foliar treatments did not affect the anthocyanins, flavonols, hydroxyci nnami c aci ds, or sti l benes, but increased the flavanol content in the grapes. Conclusions and significance The effect of foliar treatments was season-dependent, which can be explained by the differences in preharvest rainfall between vintages. The influence of season on grape phenolic compounds was greater than that of the treatments. The results offer information about the response of grapevine to foliar application under different climate conditions.

In recent years, foliar application of elicitors to the vineyard has been increasingly used, in particular, elicitation with methyl jasmonate (MeJ). However, due to the high cost of this compound, it is necessary to find a form of application in which the amount to be used is considerably reduced. Therefore, the aim of this work was study for the first time the influence of foliar application of nanoparticles doped with MeJ (ACP-MeJ) and foliar application of methyl jasmonate (MeJ), using a dose of 1 mM versus 10 mM, respectively, on volatile composition of Tempranillo grapes during two consecutive vintages. Grape volatile composition was determined by SPME-GC-MS. The obtained results reveal that MeJ application increased the concentration of terpenoids, and total C6 compounds in 2019 and 2020, and C13 norisoprenoids in 2019. In addition, ACP-MeJ enhanced the amount of terpenoids, and benzenoids in 2020. These are encouraging results considering that the ACP-MeJ dose was 10 times lower than that of MeJ. Therefore, the foliar application of MeJ supported on nanoparticles could be a tool in order to improve grape volatile composition, favoring a more viable and sustainable viticulture.

Nanoparticles are emerging as a cutting-edge technology to improve crop agricultural input efficiency and reduce biotic and abiotic stresses. In viticulture, nanoparticles hold promise for the sustainable application of an elicitor (methyl jasmonate, MeJ), allowing a considerable dosage reduction. Herein, the influence of the foliar application of free MeJ (10 mM) and MeJ nanoformulation (ACP-MeJ, 1 mM MeJ) on Tempranillo grape amino acids content over two vintages (2019 and 2020) was evaluated. While both MeJ treatments provided a significant increase of the amino nitrogen and yeast assimilable nitrogen in the must in 2019, there were no significant differences on these parameters in 2020. In 2019, MeJ treatment enhanced the synthesis of most of the amino acids included in this study, while ACP-MeJ promoted the formation of six amino acids. Hence, the content of total amino acids, with and without proline, was higher after applying MeJ than in the control musts. However, these values were higher for control must than for MeJ samples in 2020. The multivariable analysis confirmed that the vintage factor had a more prominent effect on the overall parameters of the musts. This strong influence of the vintage could be related to the higher rainfall in 2020.

BACKGROUND: Grape nitrogen composition directly affects the development of alcoholic fermentation and also influences the final wine aromatic composition. Moreover, different factors influence grape amino acids composition, such as rate and timing of nitrogen application. The aim of this study was to determine the influence of three doses of urea, applied at two different phenological stages (pre-veraison and veraison), on the nitrogen composition of Tempranillo grapes during two consecutive seasons. RESULTS: Urea treatments did not affect vineyard yield, oenological parameters of the grapes and yeast assimilable nitrogen. However, amino acids concentration in the musts increased at both moments of urea application (pre-veraison and veraison), but the lower urea concentrations and sprayed at pre-veraison improved most of the amino acids in the musts, during two vintages. Moreover, when the year was rainy, the higher dose treatment (9 kg N ha) applied at pre-veraison and veraison improved the amino acid concentration in the must. CONCLUSION: Foliar applications of urea could be an interesting viticulture practice in order to increase the amino acids concentration in Tempranillo musts.

BACKGROUND: Grape aromas are formed by a great number of volatile compounds. Methyl jasmonate (MeJ) and urea (Ur) foliar applications have been studied to improve grape quality, but their combined application has never been studied. RESULTS: In both seasons, MeJ application enhanced terpenoids and C6 compounds synthesis, though decreased alcohols content. Moreover, MeJ + Ur treatment reduced benzenoids and alcohols and did not affect C-norisoprenoids content. However, there was no clear effect of these treatments on the rest of the volatile compounds. Multifactorial analysis showed a season effect on all volatile compounds, except terpenoids. Discriminant analysis showed a good separation among samples under treatment criterion. The great effect of MeJ treatment on terpenoids was probably due to this elicitor influencing their biosynthesis. CONCLUSION: Season has a strong influence on grapes aromatic composition since it affects all volatile compound families except terpenoids. MeJ foliar application enhanced terpenoids, C-norisoprenoids and C6 compounds synthesis, whereas decreased alcohols content; however, MeJ + Ur foliar treatment did not affect C-norisoprenoids and C6 compounds, and decreased benzenoids and alcohols grape compounds. Therefore, no synergistic effect was observed between Ur and MeJ on grape volatile compounds biosynthesis. Foliar application of MeJ seems to be sufficient to improve the aromatic quality of grapes. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Greenhouse gas (GHG) emissions are influenced by physical, chemical, biological, and anthropogenic factors. The objective of the study is to carry out a comprehensive analysis of the emissions of three important agricultural GHGs (CO2, N2O, and CH4) in both rows and alleys of a vineyard (1) and to understand their interactions with the agricultural operations carried out in the experimental plot, namely tillage, inter-row management, application of mineral and organic fertilizers, and irrigation and pruning, as well as the agroclimatic conditions of the plot (2). The study was conducted in a vineyard of Vitis vinifera L. cv. Tempranillo blanco in the DOCa. Rioja grape-growing region, during 2017, 2018, and 2019. Cumulative CO2 emissions were highest in 2018, reaching 934.7 ± 66.5 kg ha−1 day−1 in the alleys and 926.8 ± 76.5 kg ha−1 day−1 in the rows, in agreement with the wetter year and organic matter decomposition at the end of 2017. N2O emissions during the three-year study were mainly affected by mineral fertilizer application, with increases of 41.1 g ha−1 day−1 in the alleys and 49.3 g ha−1 day−1 in the rows during 2018, and 33.1 g ha−1 day−1 in the alleys and 39.6 g ha−1 day−1 in the rows in 2019. Regarding CH4, anaerobic soil conditions in 2018 (the year with the highest rainfall) led to the highest flux of CH4 emissions to the atmosphere, with 215.5 ± 51.0 g ha−1 day−1 in the corridors and 238.4 ± 54.9 g ha−1 day−1 in the rows. This study emphasizes the complex interplay of physical, chemical, biological, and human-related factors affecting GHG emissions in viticultural soils. Understanding these dynamics is essential for developing sustainable vineyard practices that minimize emissions and contribute to climate change mitigation.

Methyl jasmonate (MeJ) is an elicitor that, when applied in the vineyard, can improve grape quality. There are several studies about the MeJ influence on red grape varieties; however, to our knowledge, there is little information about white grape varieties, specifically Tempranillo Blanco. Therefore, the aim of this work is to evaluate the effect of MeJ foliar treatments, carried out at veraison and post-veraison, on the aromatic, phenolic and nitrogen composition of Tempranillo Blanco grapes. The results showed that grape volatile compounds content increased after MeJ application, especially terpenoids, C13 norisoprenoids, benzenoids and alcohols, and, in general, mainly at post-veraison. Regarding phenolic and nitrogen compounds, their concentrations were enhanced after MeJ treatments, regardless of application time. Consequently, MeJ treatment improved grape volatile, phenolic and nitrogen composition, particularly when this elicitor was applied post-veraison. Therefore, this is a good and easy tool to modulate white grape quality.

La composición volátil de la uva es uno de los parámetros más importantes para determinar la calidad del mosto y del vino. Los aromas de la uva, también llamados primarios, se dividen en aromas varietales y prefermentativos. Estos compuestos se encuentran en muy bajas concentraciones en la uva, por lo que, para llevar a cabo su identificación y cuantificación, se requiere de un método eficaz de extracción para su posterior análisis cromatográfico. El análisis de compuestos volátiles de las uvas mediante métodos cromatográficos presenta numerosos inconvenientes, como el consumo de tiempo, la pérdida de muestra y preparación de la misma, los costes de reactivos e instrumentación y la necesidad de personal formado, por lo que estos equipos solo están disponibles en algunos centros de investigación y en grandes bodegas. Actualmente no existe ningún método que permita realizar análisis rutinarios a tiempo real de la composición aromática de las uvas a lo largo de su maduración, hecho que le permitiría al viticultor tomar decisiones respecto a las prácticas vitícolas, a la elección de la fecha de vendimia o a la clasificación de la uva en función de su calidad aromática. Este hecho ha cobrado mayor importancia en los últimos años debido al desequilibrio entre la madurez industrial (contenido de azúcares/ácidos) y las madureces fenólica y aromática en la uva, provocado por el efecto del cambio climático. Como consecuencia del mismo, las bayas alcanzan más rápidamente el contenido adecuado de azúcares (medidos como sólidos solubles totales (TSS, Total Soluble Solids) (ºBrix)), pero no de compuestos fenólicos y aromáticos (compuestos que se sintetizan más tarde en la baya). En los últimos años se han desarrollado métodos rápidos y no destructivos que permiten relacionar datos espectrales con la concentración de componentes químicos específicos (TSS, compuestos fenólicos, compuestos aromáticos, compuestos nitrogenados…). Dos de estas tecnologías son la espectroscopía de infra, Para ello, en primer lugar, se optimizaron tres técnicas para la extracción de compuestos volátiles en mosto: extracción mediante barrita agitadora absorbente (SBSE, Stir Bar Sorptive Extraction), su variante multi-SBSE (mSBSE), en la que se utilizaron barritas agitadoras de polidimetilsiloxano (PDMS) y de etilenglicol (EG) de forma simultánea, y microextracción en fase sólida mediante película fina (TF-SPME, Thin Film – Solid Phase Microextraction), en la que se probaron las películas finas de PDMS/carboxen (PDMS/CAR) y de PDMS/divinilbenceno (PDMS/DVB). Los factores optimizados fueron el modo, velocidad, tiempo y temperatura de extracción, y la adición de NaCl. A su vez, se puso a punto el análisis de dichos compuestos por cromatografía de gases-espectrometría de masas (GC-MS, Gas Chromatography – Mass Spectrometry). Una vez optimizadas las tres técnicas, se eligió la que mejores resultados proporcionó, que fue TF-SPME-GC-MS, con la película fina de PDMS/CAR y bajo las condiciones de inmersión directa (DI), a 500 rpm, durante 6 horas a 20 ⁰C. Dicha técnica se utilizó posteriormente como método de referencia para la determinación de compuestos volátiles en las muestras de mosto. En segundo lugar, se tomaron medidas espectrales, en condiciones de laboratorio, de 240 muestras de Vitis vinifera L. Tempranillo y 240 de Tempranillo Blanco, recogidas durante los años 2019 y 2020, mediante HSI en el rango 400-1.000 nm y mediante NIRS en el rango 1.100 – 2.100 nm. En tercer lugar, se midieron los TSS y se analizaron los compuestos volátiles de esas mismas muestras con el método TF-SPME-GC-MS optimizado, se integraron los cromatogramas y se obtuvieron, de esta forma, los datos de referencia. Por último, se construyeron los modelos de calibración multivariante, mediante regresión por mínimos cuadrados parciales modificados (MPLS), utilizando los datos espectrales adquiridos y los datos de referencia. Los resultados obtenidos demostraron que las técnicas HSI y NIRS permiten d

Phenolic compounds are very important for grapes and wines quality since these compounds can take part in color, mouthfeel and wine ageing potential, and they are also related to the human healthy properties of moderate wine consumption. The content of phenolic compounds in grapes depends on different factors, such as variety, climatic and geographical factors, cultural practices, and the stage of grape ripeness. Foliar application of biostimulants has been studied in the last years in order to mitigate the effect of climatic change in grapes and to enhance their composition and quality. In this work, it was studied the effect of foliar application of methyl jasmonate plus urea (MeJ + Ur), in Tempranillo vineyard, on the content of phenolic compounds in grapes and wines, during two consecutive vintages. These compounds (anthocyanins, flavanols, flavonols, phenolic acids, and stilbenes) were analysed, in both grapes and wines, by high performance liquid chromatography (HPLC). The effect of foliar treatment was season dependent, probably due to the differences in pre-harvest rainfall recorded. In the first season, the MeJ + Ur treatment favored the biosynthesis of anthocyanins, increasing their content in grapes; however, this effect was not observed in the wines. In the second vintage, the MeJ + Ur foliar application did not enhance the anthocyanin content in grapes or in wines. With respect to the other phenolic compounds, the foliar treatment did not improve their content in grapes, except for total flavonols in the second vintage. Foliar application of MeJ + Ur seems to be a good tool in order to enhance the anthocyanin content in grapes, which it is very interesting due to anthocyanins are the main phenolic compounds in red varieties, and they are responsible for the wine red color. Nevertheless, further studies should be carried out to achieve a better knowledge of the plant response to this treatment according to the climatic conditions. Moreover, it is necessa