Effects of shading nets as a form of adaptation to climate change on grapes production: a review

Viticulture worldwide is threatened by the environmental modification caused by climate change. Higher temperature and atmospheric CO2 concentration determine an acceleration of the ripening process, which can be detrimental to wine quality. Hence, adaptation and mitigation strategies are necessary to reduce heat and water stress and improve the qualitative production levels. Amongst all the various techniques available, shading nets represent an interesting alternative for their effects on canopy microclimate and grape production. However, these effects vary strongly depending on the intensity of the shading treatment, the timing of its application, environmental conditions, and differences in cultivar response. The reduction in photosynthetic activity can improve water use efficiency and slow down the ripening process, preserving must acidity. Phenolic compounds, which benefit from light exposure for their synthesis, are negatively affected by shading, while aromatic composition can be improved by it. Vine reserve accumulation is reduced by the lower photoassimilates production. Photoselective nets, thanks to their colour, not only reduce light intensity but also change the quality of the light spectrum reaching the canopy, thus, determining specific responses in the plants

Adaptation Strategies to Climate Change in Vineyard: innovation in vine training and pruning system, and cover crops

Il cambiamento climatico sta causando non pochi problemi nelle regioni storicamente vocate alla viticoltura. Frequentemente le uve tendono ad essere squilibrate, caratterizzate da elevati contenuti zuccherini, alti livelli di pH e bassi contenuti di acidi. Nelle stagioni 2020, 2021 e 2023, viti allevate a Guyot sono state messe a confronto con viti allevate e potate con un sistema innovativo, denominato High Cane. L'innovazione, che consiste nell'aumentare la distanza del capo a frutto dal suolo, senza modificare l'originaria altezza del tronco, ha portato ad un aumento del numero di gemme e dei germogli per ceppo e ad una modifica dell’architettura della chioma, più bassa e spessa, caratterizzata da una maggiore produzione e di conseguenza da un minor rapporto tra superficie fogliare e produzione. Alla vendemmia le viti HC hanno mostrato una riduzione del contenuto di solidi solubili rispetto alle viti Guyot (-17%, -3%, -10% rispettivamente nel 2020, 2021 e 2022), una significativa riduzione del pH, associata a un aumento dell'acidità totale (+15%, +9%, +19% rispettivamente nel 2020, 2021 e 2022). A partire dalla semina, effettuata ad ottobre 2020, nelle stagioni 2021 e 2022, sono state confrontate tre tipologie di gestione del suolo in vigneto, un miscuglio di graminacee e leguminose (T1), una coltura di copertura di Trifolium alexandrinum (T2) e un inerbimento naturale spontaneo del vigneto (T3). Le viti delle tesi T1 e T2 hanno mostrato una maggiore vigoria ed una maggiore produzione per ceppo, con valori significativamente più elevati. Anche i parametri qualitativi delle bacche ne hanno risentito, alla vendemmia, le viti delle tesi T1 e T2 hanno mostrato un contenuto di solidi solubili inferiore rispetto alle viti della tesi T3 (-3,85 e -3,36 °Brix, rispettivamente per T1 e T2 nel 2021, -4,14 e -5,09 °Brix rispettivamente per T1 e T2 nel 2022), e una significativa riduzione del pH, con valori rispettivamente di 3,01, 3,05, 3,13 nel 2021 e 2,97, 2,97, 3,08 nel 2022 per T1, T2 e T3. A questi valori è stato associato un aumento dell'acidità totale, pari a + 0,58 g/l e + 0,52 g/l nel 2021 per T1 e T2 rispetto a T3 e + 0,36 g/l e + 0,60 g/l nel 2022 per T1 e T2 rispetto a T3. Anche il contenuto di APA nel mosto è migliorato in T1 e T2 rispetto a T3 in entrambi gli anni di prova.Climate change is causing many problems in regions historically suited to viticulture. Frequently, grapes tend to be unbalanced, characterized by high sugar contents, high pH levels and low acidic contents. In the 2020, 2021 and 2023 seasons, the traditional Guyot training system vines was compared with vines trained and pruned with an innovative system, called High Cane. The innovation, consisted in increasing the distance of the cane from the soil, without changing the height of the trunk, led to an increase in the bud number and in shoot per vine and to a modification of the canopy architecture, low and thick, characterized by a higher yield and consequently by a lower fruit-to-yield ratio. At the harvest, the High Cane vines showed a reduction in total soluble solids compared to Guyot vines (-17%, -3%, -10% in 2020, 2021 and 2022 respectively), a significant reduction in pH, which was associated with an increase in the total acidity (+15%, +9%, +19% in 2020, 2021 and 2022 respectively). Starting the seeding in October 2020, in 2021 and 2022 seasons, three types of cover crop management, a grass-legume mixture (T1), a cover crop of Trifolium alexandrinum (T2) and a spontaneous natural covering (T3), were compared in vineyard and their effects on yield and qualitative parameters were registered. The vines of T1 and T2 theses improved the vigor of the vineyard and yield (6.84, 6.41 and 4.09 kg/vine in 2021 for T1, T2 and T3 respectively, 5.15, 5.80 and 2.73 kg/vine in 2022 for T1, T2 and T3 respectively). Also qualitative parameters of berries were affected, at harvest, the Trifolium alexandrinum and the grass-legume mixture vines showed a lower total soluble solids content compared to natural covering vines (-3.85 and -3.36 °Brix, respectively for T1 and T2 in 2021, -4.14 and -5.09 °Brix respectively for T1 and T2 in 2022), and a significant reduction in pH, with values of 3.01, 3.05, 3.13 in 2021 and 2.97, 2.97, 3.08 in 2022 for T1, T2 and T3 respectively. These values were associated with an increase in the total acidity, equal to + 0.58 g/l and + 0.52 g/l in 2021 for T1 and T2 respect to T3 and + 0.36 g/l and + 0.60 g/l in 2022 for T1 and T2 respect to T3. Also the YAN content in must was improved in T1 and T2 respect to T3 in both years of trials

Innovative vine training system as a strategy for adaptation to climate change on Verdicchio

Grape quality is endangered by thermal increase caused by climate change. Hence, the necessity to find adaptation solutions moved research activities in the last few years towards experimenting innovative management techniques. In this trial an innovative training system, called High Cane, was compared with the traditional Guyot. High Cane trained vines showed lower photosynthetically active solar radiation values at the fruiting zone, a higher number of shoots per vine and total yield. At harvest, High Cane proved to have some effects in slowing down ripening, i.e. showing lower sugar content, higher titratable acidity and lower pH. The innovative training system is a candidate to be a valid strategy for the adaptation to the effects of climate change

Analysis of Verdicchio harvest data in Matelica appellation area during the 1989-2016 time series

The knowledge of the climatological trend of an area and its influences on grapevine growth is a helpful tool for the prediction of the ripening process: climate change effects on viticulture can be thus studied. In a first step, the climate of the Matelica area, central Italy, was characterized, then Verdicchio grapevines harvest data and its connection with seasonal trends have been evaluated for a period of almost thirty years. This study allowed us to find a connection between mean harvest date and heat summation from March to June, while berry sugar accumulation proved to be more influenced by the heat summation of June-August period. These relations can represent a useful tool for wineries and vine-growers to monitor the ripening process and prediction of harvest, helping in their management

Seasonal evolution impact on Montepulciano grape ripening

Abstract. In an environmental background characterized by climate change, the seasonal trend increasingly affects the qualitative and quantitative expression of the vineyards. The sugar concentration, titratable acidity, the ratio sugar/acids and yield were related with heat accumulation (growing degree days accumulation), calculated in different period of grapevine cycle. The 21.5 °Babo threshold has been reached by Montepulciano grapes in the various years (2007-2019) even with 40 days difference. Over a period of 13 years, the sugar of Montepulciano grapes was influenced by thermal evolution between March to July. The relationship with high coefficient determination (R2 0.74) was obtained between heat accumulation and titratable acidity. According to this forecasting model, increases in heat accumulation of 100 degree-days in the period from March to June correspond to a reduction of about 0.85 g/l of acidity of the must at the harvest associated with an increase of 0.75 degree-days in the ratio between sugars and acids. The thermal evolution between June and July was correlated with yield of Montepulciano, an increase of 100 degree-days is associated with a decrease of about 1.86 t/ha. The thermal evolution between March and July is crucial for yield and grape quality of Montepulciano

Seasonal evolution impact on Montepulciano grape ripening

In an environmental background characterized by climate change, the seasonal trend increasingly affects the qualitative and quantitative expression of the vineyards. The sugar concentration, titratable acidity, the ratio sugar/acids and yield were related with heat accumulation (growing degree days accumulation), calculated in different period of grapevine cycle. The 21.5 °Babo threshold has been reached by Montepulciano grapes in the various years (2007-2019) even with 40 days difference. Over a period of 13 years, the sugar of Montepulciano grapes was influenced by thermal evolution between March to July. The relationship with high coefficient determination (R2 0.74) was obtained between heat accumulation and titratable acidity. According to this forecasting model, increases in heat accumulation of 100 degree-days in the period from March to June correspond to a reduction of about 0.85 g/l of acidity of the must at the harvest associated with an increase of 0.75 degree-days in the ratio between sugars and acids. The thermal evolution between June and July was correlated with yield of Montepulciano, an increase of 100 degree-days is associated with a decrease of about 1.86 t/ha. The thermal evolution between March and July is crucial for yield and grape quality of Montepulciano