OENO One (Mar 2021)
Mechanical pruning and soil organic amending in vineyards of Syrah: effects on grape composition
Abstract
The interaction of mechanized pruning systems and soil organic amending is a way to increase vine productivity. However, since the increase in productivity may have effects on grape composition, this study aims to understand the effects of the interaction between these two practices. Two trial fields were implemented on Shiraz vineyards in 2 different wine regions. Mechanical hedge pruning was compared with hand spur pruning and four different organic amendments were tested: biochar; municipal solid waste compost; cattle manure; sewage sludge. Mechanical pruning reduced grapes total soluble solids and pH and no effects on other parameters. Organic amendments also reduced total soluble solids, especially sewage sludge, and tended to reduce total anthocyanins and total phenols. The effect of the interaction between both factors on grape composition was never significant. A negative relation between yield and total soluble solids was observed, while total acidity had no relation with yield. Total anthocyanins were also negatively related with yield. A positive relation between grapes sugar content and total anthocyanins is reported. The presented results show that the interaction between mechanical pruning and soil organic amending is a powerful tool to increase productivity without significantly affect grapes composition. However, some reduction in some quality parameters show that however mechanical pruning does not significantly affect grape quality, the choice of the organic amendment and its amount, must be done considering the destiny of produced grapes.
