Increasing the yield of Nebbiolo grapevines grown in acid soils: a comparison of different techniques

The detrimental effect of soil acidity on the performance of vines can be attributed to both P deficiency and Al toxicity stresses. This study aimed to investigate the effect of different agronomical techniques applied in a vineyard of Nebbiolo to solve the problem of low productivity due to low soil pH. The effect of liming, phosphorus fertilization and pre-bloom shoot trimming on yield and bud fruitfulness was followed over a period of 3 years. Moreover, in the last year of study grape analyses were performed to assess treatments’ effect on grape quality. Results confirmed that it is possible to alleviate in part the low productivity due to low soil pH. Overall, pre-bloom shoot trimming, P fertilization, and the combination of these two treatments have been the most effective options. Regarding the differences between treatments, only the combination of pre-bloom shoot trimming and P fertilisation significantly affected bud fruitfulness and yields in comparison to untreated. Little or no effect has been observed among treatments in terms of grape composition at harvest.