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Biochemical parameters are particularly suited to evaluate soil fertility because soil microorganisms play a pivotal role in determining soil quality and functionand are very sensitive to changes in soil management and environmental conditions. For such reasons, in this work, we used several biochemical indexes to assess the effect on soil fertility of 3 different conservative management systems of vineyards. The managements compared were chemical weed control vs permanent grass (CWC/MWC), land levelling vs undisturbed soil (LL/US), conventional farming vs organic farming (CON/ORG). The following parameters were determined in 2014 and 2015 on soil samples: total organic C (TOC), extractable N (EN), soil basal respiration (SBR), microbial biomass C (BC), microbial quotient (BC/TOC) and metabolic quotient (qCO2 = SBR/BC). Results showed that biochemical indicators were effective in detecting changes in soil fertility between compared systems. In particular, conservative systems (MWC, US and ORG) showed a larger and more efficient microbial biomass and enhanced EN content in comparison to the relative conventional systems. Furthermore BC/TOC and qCO2 indicated higher C use efficiency in conservative systems. Results as a whole indicate that conservative management systems aimed to maintain and enhance soil organic matter displayed a higher level of soil fertility.

Leaf removal is a viticultural practice applied in order to improve fruit-zone microclimate and berry quality. The aim of this trial was to evaluate the effect of post-flowering leaf removal on maturation and biosynthesis of terpenes and and C13-norisoprenoids in Ribolla Gialla grapes. In the seasons 2015 and 2016, basic maturation parameters were nearly unaffected by leaf removal. Contrarily, in the second season, 2016, one week before harvest, the concentration of several aroma compounds was significantly improved by leaf removal. In conclusion, the trial here showed that leaf removal improves the concentration of aroma compounds in the grapes, but the selection of the date of harvest is more crucial in order to maintain them during vinification.