Optimizing Artificial Shading for Microclimate, Yield, Leaf Nutrient and Economic Benefits in Sinceri (V. vinifera L.) Grape Cultivation

This study was conducted on the Sinceri grape cultivar grown for both table and raisin (drying) purposes, in the 2021 growing season in Siirt/Türkiye. The primary objective was to create a microclimate within the vine canopy by installing net covers with different shading rates (35%, 55%, and 75%) during the veraison period, thereby delaying the harvest and obtaining high-quality, high-yield grapes. Regarding phenological development, the period between full bloom and harvest was the shortest under the 55% shading treatment, which also recorded the lowest mean temperature (28.54 °C) and the lowest Effective Heat Summation (EHS) value (1965.70 dd). The highest mean temperature (26.28 °C) was observed under the 75% shading treatment, while the highest EHS value (2401.05 dd) was recorded under the 35% shading treatment. In terms of yield compared to the control, the 35% shading treatment provided a 21.75% increase, the 55% treatment yielded a 57.44% increase, and the 75% treatment led to a 37.45% increase. Furthermore, it was determined that all shading treatments increased the macro- and micronutrient contents in grapevine leaves. Economic analyses for the Sinceri grape cultivar revealed that the shading treatments had a statistically significant effect on yield. In conclusion, the net cover with a 55% shading rate proved to be the most effective treatment.