Comparison among mid-row soil managements techniques to preserve grape quality in Cabernet Sauvignon vines

Conservative technique of soil management plays an important role, compared to conventional tillage, in order to save soil fertility, to preserve biodiversity and to maintain vegetative-productive balance. However, alongside the many agronomic and environmental benefits, it is worth to consider that grass cover exerts water and nutritional competition, especially where irrigation is difficult to set up. This research is aimed to evaluate the effects, on vines physiology and quality of the grapes, of three different soil management: temporary sward over all interrows (IT), green manure and tillage every other row (SL) and mulching with plant residues and tillage every other row (PL); measurements were carried out in 2016 and 2017 on a Cabernet Sauvignon vineyard, in Bolgheri (Tuscany). During the experiment, single leaf gas exchanges, stem water potential, productivity were measured, while quality parameters were analyzed. Significant differences in gas exchanges related to the different season and inter-row management were observed. Compared to SL and PL, the IT showed more negative values of water potential, due to the grass-vine competition, especially when water availability is greater. The competition, exerted by sward, at the beginning of the season 2017, lead to differences in fruit setting with impact on yield; therefrom, significant differences also in anthocyanic content.