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.
Grapevine root distribution and density influence mineral and water absorption and are affected by soil management and the use of cover crops. This study, conducted in a ten-year-old commercial Mediterranean vineyard with desiccant-managed inter-rows, compares the effects of three different soil management practices—minimum tillage (MT), spontaneous natural covering (NC), and a commercial grass mixture (GM)—on root development in Montepulciano vines grafted onto Kober 5BB rootstocks. Root length, diameter, and weight across different soil layers were analyzed by digging trenches. The results show that thin roots, primarily responsible for water and nutrient absorption, ensure greater soil volume exploration, while medium-to-large roots contribute mainly to root biomass. The presence of cover crops reduces root development in the upper soil layers due to competition with herbaceous species; however, this promotes deeper root exploration and increases the total root length per plant. In the deeper soil layers, root growth is limited by higher soil compaction. Tillage enhances the development of medium-to-large roots and increases the total root biomass per plant. In conclusion, soil management influences vine root development, and competition from cover crops stimulates the growth of absorbing roots in deeper soil layers.
Rising temperatures due to climate change pose a significant threat to viticulture, intensifying summer heat stress and accelerating berry ripening. Additionally, the increasing frequency of extreme weather events, such as hailstorms, further jeopardizes the sustainability of the viticultural sector. In recent years, mitigating these impacts has become crucial for grape production, particularly in Mediterranean regions. This study compares two mitigation strategies—using an anti-hail shading net (S) and kaolin spraying (K)—with untreated control vines (C) over three growing seasons. Vine physiology, berry ripening, grape production and pruning weight were evaluated. The S treatment significantly reduced light interception in the fruiting zone and, while limiting gas exchange, improved vine performance during extreme heat. The K treatment alleviated heat stress and enhanced the photosynthetic activity. Both S and K treatments improved grape quality by maintaining higher acidity levels and lower sugar concentrations and pH. Additionally, both treatments reduced the incidence of fungal diseases, with the net providing added protection against hailstorms. No significant changes in pruning weight were observed, and the treated vines showed a better balance between vegetative growth and production. In conclusion, both kaolin and shading nets are effective techniques for addressing the challenges of climate change, enhancing vine resilience and ensuring high-quality grape production.
Natural covering (NATC) has spread on hillside vineyards of central Italy as a replacement for tillage to reduce soil erosion, although it increased nitrogen and water needs. Therefore, in the current context of global warming, using cover crops (CCs) that require less water and provide nitrogen becomes crucial. The effects of two low-competition legume-enriched CCs in a rainfed hillside vineyard—a perennial legume–grass mixture (PLGM) and an annual legume cover crop of Trifolium alexandrinum (ALTA)—were compared with NATC over three years. PLGM and ALTA provided good levels of soil coverage, slightly lower than NATC, which had a negligible presence of legumes. PLGM and ALTA, due to low competition, enhanced vine vigor, resulting in thicker and wider canopies (as indicated by total leaf area and leaf layer number), higher pruning weight, and increased yield. PLGM and ALTA led to good qualitative levels, with higher grapes acidities, lower pH and total soluble solids content and, additionally, significantly higher yeast assimilable nitrogen content. In conclusion, implementing low-competition legume species in CCs is an effective tool to avoid soil erosion in a climate change scenario, leading to increased productivity, higher acidity, and improved nitrogen content in the grapes.
The thermal increase, due to the changed climatic context, is leading to marked variations in the yield and quality of the grapes and causing an increase in the use of water resources in several viticultural areas. Nevertheless, in some environments, rainfalls are scarce and there is no water availability. In this study, we compared the impact of low water irrigation volumes (DI, replacement of 70% of crop evapotranspiration) with respect to non-irrigated vines (NI), on the physiological, yield and qualitative performances of near-isohydric variety ‘Montepulciano’, trained to overhead trellis system, which requires a high-water supply. The stomatal conductance and photosynthesis values, in basal and median leaves, were higher in DI vines. All NI leaves suffered water stress, showing in the youngest leaves (position 20 and 25 along the main shoot) higher carbon isotope discrimination (δ13C) (− 25.38‰ and 25–25.77‰, respectively). At harvest, DI vines showed yield higher of 30% and 33% than NI vines in 2005 and 2006, respectively, and 18% in 2007. In environments with prolonged water shortage and low water resource, near-isohydric ‘Montepulciano’ vines, trained to overhead trellis system and irrigated with limited volumes, determined a significant improvement of ‘vineyard efficiency’ with a yield of 19.2 t/ha with respect to 13.4 t/ha of NI vines, ensuring also more sugar content (+ 31%), anthocyanin concentration (+ 13%) and polyphenolic substances (+ 8%) than NI vines.
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.