Abstract
Nutrition is a key step for the seasonal and future performances of the vineyard. Nevertheless, its effectiveness is connected to environmental conditions such as soil and climate. Lean areas show little nutrient availability but at the same time produce renowned wines. Under these conditions, and in the face of climate change, viticulture is in a delicate balance that requires more sustainable alternative for fertilization management. This study aimed at comparing the use of a NPK fertilizer with controlled-release nitrogen (CRN) with a traditional granular fertilizer (NPK) for mineral nutrition of Glera vineyards in the Magredi area of Cellina-Meduna, Friuli Venezia-Giulia (Italy). This geographic area is characterized by soils typically poor in nutrients and prone to fertilizer loss due to their gravelly texture and consistent rainfall. Plant and soil responses to fertilization over 2022 season, characterised by a period of severe drought, were evaluated by measuring foliar chlorophyll content, yield per plant, Ravaz index, fruit quality and nitrate concentration in soil and leached water. The results showed that the use of CRN maintained a yield comparable to that of conventional fertilization and improved some quality parameters, such as acidity, organic acids and YAN content. Plant uptake of N was higher in the controlled-release fertilizer (CRN) treatment, as shown by SPAD measurements. Soil and water analysis showed that nitrate loss through rainfall events was lower in the CRN treatment. These results suggest that CRN could be an effective alternative to traditional fertilization in gravelly soils, with benefits to the plant and the environment.