Exploring the contributions of terroir factors on berry quality of cvs. Cabernet-Sauvignon and Merlot (Vitis vinifera L.) at the Eastern Foothills of the Helan Mountains region of China

Abstract

Terroir leaves its mark on the accumulation of flavours in grape berries, triggering biochemical re-actions and ultimately shaping wine styles. However, the complicated relationship between terroir and grape quality remains not fully understood. We investigated biochemcial profiles of ripened berries in two major grape cultivars Cabernet Sauvignon and Merlot during two consecutive vintages across the Eastern Foothills of the Helan Mountains at Ningxia region, which is a blooming wine region in China. The corresponding terroirs and the fruit carbon stable isotopes (δ¹³C) were measured. Results indicated that organic acids and anthocyanins exhibited a strong vintage effect, with the cooler vintage exhibiting higher levels of these compounds relative to the warmer vintage. The Mantel test identified several critical factors influencing berry biochemical compositions, including total soil phosphorus (Tp), total soil potassium (Tk), soil thickness (Thickness), precipitation (April-September precipitation, Pre4-9), temperature diurnal range (May, July, August, September, DR-5 and DR 7-9), and δ13C. These results contribute to a scientific foundation for grape cultivation in the Eastern Foothills of the Helan Mountains region and can help growers to better understand and control the production of fruits that maximize their grape typicity.