Terroir effects on wine aromatic metabolomics in the eastern foot of Helan Mountain, Ningxia, China

Aim: The eastern foot of Helan Mountain, Ningxia, China is one of the most important wine production regions in China and grape cultivation has spread in several sub-regions with different soils and cultivars. Large diversity in wine aromas have been observed at Ningxia region but which terroir factors drive those diversity in aromas remain to uncover. This study aims to investigate the impacts of grape varieties and soil chemical properties on wine aromas at Ningxia, in order to characterize the aromatic typicality of Ningxia wines and provide foundation for developing a ‘Protected Designation of Origin’ system. 

Methods and Results: Twenty-six representative wineries from 5 sub-regions of Ningxia were selected, and their vineyard soils were analysed at 20, 40, and 60 cm. Soil electric conductivity, organic carbon, available N, P, K, and total N, P, K, Na, Mg, Ca were quantified. Forty wines from those wineries made from cvs Cabernet Sauvignon, Cabernet Franc, Merlot, etc were also sampled, and their aroma profiles were analysed with GC-MS. Wine aromas showed large diversity, and principal component analysis showed that the key discrimination factor was the variety. Wines from Cabernet Sauvignon, Cabernet Franc, and Merlot exhibited distinct aroma profile, while vineyard location only had minor discrimination contribution. Further analysis for each variety revealed that the wines from Cabernet Sauvignon had quite distinct aromas from different vineyard locations. Soil chemical properties showed clear differences between regions, particularly the quantity of total N, K, and Mg. Correlation network analysis further identified strong and interesting linkages between specific aroma compounds and soil chemical properties. 

Conclusions: 

Our study found both wine aroma and soil chemical properties showing large diversity at Ningxia region. Grape variety plays a key role in determining wine aroma, while vineyard location with different soils can finely tune wine aroma for a given variety. 

Significance and Impact of the Study: Our results established the interaction between soil properties and genotypes on wine aromas. It highlights the importance to consider the matching between grape variety and soil type for designing future geographic regulation of wine production in Ningxia.