THE INFLUENCE OF HAIL AND TREATMENTS WITH AMINO-ACIDS ON THE FERTILITY AND BIOLOGIC BALANCE OF GRAPEVINES

Abstract

Climatic accidents increase in frequency due to climatic changes. Hailstorms are typically localized events and are known few studies about their effect on grapevine. The objective of this study was to examine the vine vegetative balance responses to natural hail, registered when shoots were 10-15 cm height. Four grape cultivars (Vitis vinifera L.), two for red wine (Feteascǎ Neagrǎ, Pinot Noir) and two for white wine (Chardonnay, Tǎmȃioasǎ romȃneascǎ) were studied in Dealu Mare, one of the most known vineyards in Romania. Visibly, the extent of the hailstorm damage was great, enough to injure or remove about 90% of shoots growth till hail fall. Three treatments with Delfan Plus (amino-acids complex) were applied on grapevine canopy. Number of shoots/vine and number of fertile shoots/vine were counted and biologic balance of grapevine indexes were calculated. Our results indicated that natural hail affect significantly the number of fertile shoots. Delfan Plus treatments positively influenced the number of shoots and fertile shoots. Delfan Plus treatments had little influence on Recovery index, vine Balance indexes and Ensurance Coefficient after one single year of study. The capacity of recovery after hail fall, in this case, is more influenced by the grape cultivar. The present work is the first attempt to enhance our understanding on the vegetative responses of grapevines to the use of biostimulants and to natural hail, which is an extreme and complex natural phenomenon.