Comparing kaolin and pinolene to improve sustainable grapevine production during drought

Viticulture is widely practiced in dry regions, where the grapevine is greatly exposed to water stress. Optimizing plant water use efficiency (WUE) without affecting crop yield, grape and wine quality is crucial to limiting use of water for irrigation and to significantly improving viticulture sustainability. This study examines the use in vineyards of particle film technology (engineered kaolin) and compares it to a film-forming antitranspirant (pinolene), traditionally used to limit leaf water loss, and to an untreated control. The trial was carried out under field conditions over three growing seasons, during which moderate to very severe plant water stress (down to -1.9 MPa) was measured through stem water potential. Leaf stomatal conductance (gs ) and photosynthesis rate (An ) were measured during the seasons and used to compute intrinsic WUE (WUEi, defined as An /gs ratio). Leaf temperature was also recorded and compared between treatments. Bunch quantity, bunch and berry weight, sugar accumulation, anthocyanin and flavonoid contents were measured. Finally, microvinifications were performed and resultant wines subjected to sensory evaluation.Results showed that the use of kaolin increased grapevine intrinsic WUE (+18% on average as compared to unsprayed vines) without affecting berry and bunch weight and quantity, or sugar level. Anthocyanin content increased (+35%) in kaolin treatment, and the wine was judged more attractive (p-value <0.05) and slightly more appreciated (p-value < 0.1) than control. Pinolene did not increase WUEi, limiting An more than gs; grapes with this treatment contained lower sugar and anthocyanin content than control, and the obtained wine was the least appreciated. This study demonstrates that particle film technology can improve vine WUEi and wine quality at the same time, while traditional antitranspirants were not as effective for these purposes. This positive effect can be used in interaction with other already-demonstrated uses of particle film technology, such as pest control and sunburn reduction, in order to achieve more sustainable vineyard management. \ua9 2016 Brillante et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Compost application boosts soil restoration in highly disturbed hillslope vineyard

A field trial was carried out to investigate the effects of compost application on a young Cabernet sauvignon vineyard located in a hilly area in the North-East of Italy and subjected to land terracing before plantation. The use of a compost based on manure, pruning residues and pomace at a rate of 65 t ha-1 was compared to the mineral fertilization regime recommended for the vineyards in the area (NPK: 80, 50, 200 kg ha-1). A multi-factorial approach that considered soil chemical properties, microbial community structure and function, vine nutritional and vegetative indexes, yield and quality parameters was applied in the attempt of depict interrelated effects of compost on all these factors. Results of this study show that the application of compost for three consequent years greatly increased soil organic matter content and improved the mineral nutrient availability in the soil. Soil biological fertility showed a slow but significant response to compost addition as from the second year of treatment microbial growth and enzyme activity were increased compared to those of the inorganic fertilization, with special regard to enzymes involved in P cycle. A shift in the soil microbial community structure was also observed in compost-treated soil, with higher presence of copiotrophic bacteria, indicators of soil quality, and phosphorus solubilizing bacteria. A decrease of pathogenic fungal strains was also observed. Organic fertilization increased plant nutrient uptake and vegetative growth compared to those observed in chemically fertilized vines. A trend toward increased yield and improvements for some grape quality parameters such as acidity and pH were observed in the first year of production. These results provide evidence that compost can boost soil fertility restoration in vineyard disturbed by land terracing, allowing for agronomic performances comparable or even improved than those of chemically fertilized vines

Characterization of Indigenous Microbial Communities in Vineyards Employing Different Agronomic Practices: The Importance of Trunk Bark as a Source of Microbial Biodiversity

Microbiomes are essential to viticulture and winemaking since various fungi and bacteria can exert positive and negative effects on grape health and wine quality. The current work evaluates the communities of culturable fungi and bacteria associated with Corvina vines derived from two vineyards from a similar terroir (within the Valpolicella DOC area, Italy) but on which different management practices were employed: organic and conventional farming. Samples of bark and grapes were collected in four spatial points for each vineyard. Populations of bark-associated microorganisms were monitored during ripening season (at veraison and at harvest time), and results were integrated with data from grape-associated microorganisms, sampled right before harvest. Culturable populations of fungi and bacteria were determined by plate counting on WL and PCA culture media. For fungi, biodiversity was also assayed on all samples through molecular methods, by ITS-RFLP analysis. Although this does not represent a comprehensive evaluation of the microbiome, since culturable and countable microorganisms only represent a portion of microbial biodiversity, our results emphasize the importance of vine trunk bark, not only as an interesting habitat to be characterized for monitoring microbial biodiversity in vineyards but also as a potential source of microbial viable species for further isolation

The Power of the Terroir: the Case Study of Prosecco Wine

X, 248 p. 185 illus., 95 illus. in color.online r

Tuning Potassium Fertilization to Improve pH and Acidity in Glera Grapevine (<i>Vitis vinifera</i> L.) under a Warming Climate

Potassium concentration in grape berries can affect acidity and pH in must and wines. Under the current warming scenario, where preserving equilibrated value for these grape parameters is increasingly challenging, K fertilization could represent a tool to manage grape composition. In this study, the effect of potassium fertilization was investigated over 4 years (2013–2016) in field-grown grapevines (Vitis vinifera cv. Glera). Four different potassium rates (0, 15, 30, 60 kg K2O ha−1 year−1) were tested and agronomic responses, grape quality as well as K concentration in the berry were recorded over the four years. At harvest, yield parameters and total soluble solids were unaffected by potassium fertilization. On the contrary, the titratable acidity of the musts was increased by the higher rate of potassium (K60), and both tartaric and malic acids showed higher values when the K rate was higher. K fertilization did not affect the pH, as all the treatments displayed comparable pH values and in an optimal range for winemaking. Overall, in our experimental conditions, medium potassium inputs showed better results on Glera grape quality compared to low K rates, by promoting higher titratable acidity levels without altering the pH in musts

Tuning Potassium Fertilization to Improve pH and Acidity in Glera Grapevine (Vitis vinifera L.) under a Warming Climate

Potassium concentration in grape berries can affect acidity and pH in must and wines. Under the current warming scenario, where preserving equilibrated value for these grape parameters is increasingly challenging, K fertilization could represent a tool to manage grape composition. In this study, the effect of potassium fertilization was investigated over 4 years (2013&ndash;2016) in field-grown grapevines (Vitis vinifera cv. Glera). Four different potassium rates (0, 15, 30, 60 kg K2O ha&minus;1 year&minus;1) were tested and agronomic responses, grape quality as well as K concentration in the berry were recorded over the four years. At harvest, yield parameters and total soluble solids were unaffected by potassium fertilization. On the contrary, the titratable acidity of the musts was increased by the higher rate of potassium (K60), and both tartaric and malic acids showed higher values when the K rate was higher. K fertilization did not affect the pH, as all the treatments displayed comparable pH values and in an optimal range for winemaking. Overall, in our experimental conditions, medium potassium inputs showed better results on Glera grape quality compared to low K rates, by promoting higher titratable acidity levels without altering the pH in musts