Cumulative response of Tempranillo vines to the crop forcing technique and pre-forcing and post-veraison water stress in terms of yield and grape and wine quality

Abstract

Elevated temperatures during berry ripening are detrimental to grape quality. The crop forcing technique (summer pruning that ‘forces’ the vine to start a new cycle) increases must acidity and malic acid concentration at harvest by delaying the date of veraison. However, little information is available on the sensitivity to water stress of forced vines. A 3-year trial was conducted to test three irrigation strategies in forced vines: a minimum threshold of mid-day stem water potential (Ψs) of −0.75 MPa before forcing (DI), a minimum Ψs threshold of −1.2 MPa only after veraison (RDI), and the combination of both treatments (DI + RDI). Results were compared to a non-forced treatment with a minimum Ψs threshold of −1.2 MPa after veraison (C-RDI). Must acidity increased, and pH decreased in the forced treatments. However, yield was reduced by 35% and irrigation requirements increased by 20% when comparing forced and unforced treatments. As a result, water use efficiency was reduced in forced treatments. Only after a dry spring did the, DI (11%) and DI + RDI (30%) treatments, save water compared to the C-RDI treatment. Moreover, although Ψs before forcing never fell below −0.75 MPa, a significant negative correlation (R2 = 0.76) was found between the integral of water stress before the vines were forced and the number of forced bunches per vine. Post-veraison water stress in forced vines reduced the polyphenol content of the wine. Our findings suggest that forced vines are extremely sensitive to even mild water stress.

Testing field adaptation strategies for delaying grape ripening and improving wine composition in a cv. Macabeo Mediterranean vineyard

“…The later grape ripening confirmed that the temperature and humidity conditions in September and October were more favorable for a balanced grape composition. Thus, double pruning did increase the TA in relation to TSSs, and the tartaric-to-malic acid ratio in relation to TSSs, as other authors reported in other cultivars ( Gu et al., 2012 ; Martínez de Toda et al., 2019 ; Martínez-Moreno et al., 2019 ; Oliver-Manera et al., 2023 ). These increases can be beneficial for wine stability as higher titratable acidity and a low tartaric-to-malic acid ratio decrease must pH.…”

“…Moreover, given the large delay in the phenology caused by double pruning, the periods of maximum evapotranspirative demand occurred in different phenological stages than in the control or shaded vines. This may increase water requirements in forced vines as compared to the control, as Oliver-Manera et al. (2023) recently observed.…”

“…This makes this technique profitable only for premium wine production of very high commercial value. However, the carry-over effects of this technique ( Martínez-Moreno et al., 2019 ), together with its sensitivity to water deficit ( Oliver-Manera et al., 2023 ), question its feasibility. On the other hand, the addition of mulching seems to be an easy and cheap technique to implement at the plot level, and with a proven potential to alleviate the impact of vine water stress ( Buesa et al., 2021b ).…”

Factors Affecting Crop Prices in the Context of Climate Change—A Review

“…The effects of surface water irrigation shortages attributable to climate change are smaller than the direct biophysical impacts of climate change on yield on the national level. Anderson et al [52] indicated that the vines in Oliver-Manera et al [53] and olives in Ahumada-Orellana et al [54] showed great sensitivity to deficit irrigation in their yields, in their review paper.…”

Long-Term Study of the Crop Forcing Technique on cv. Tempranillo (Vitis vinifera L.) Vines and Suggested Irrigation Strategies to Improve Water Use Efficiency of Forced Vines

“…The crop forcing technique (also known as the forcing regrowth technique) has become a topic of research interest since it has proven to be a useful technique to delay the harvest date by as much as two months [3]. As a result, the berries ripen under cooler conditions with an increase in must acidity and malic acid concentration [3][4][5][6][7]. However, vines in which the crop forcing technique is carried out have a reduced yield [4][5][6][7].…”