Managing the Yield and Quality of Grapes by Calcium Supplementing on Foliar Way

Abstract

Taking into account the ecobiology and the features of nutrition in grapevine, monitoring nutrition is a process with a very dynamic balance. Present research assessed the way in which supplementary foliar fertilization with calcium can have a positive impact on grape yield, both quantitatively and qualitatively. Were used three foliar fertilizers - Fertitel, Cropmax and Waterfert - alone or associated with calcium. As indicators of the nutrition state, were analyzed the foliar area and chlorophyll content and as yield elements were evaluated mean yield per vine, mean yield per ha, and dry matter content in grapes upon harvesting. The biological material consisted of the Burgund grapevine cultivar. According to the Anova statistic analysis, trial results point to high statistic ensurance (p<< 0.001, F_calculated >> F_theoretical for Alfa = 0.001). The variation of leaf area was strongly influenced by climatic factors compared with chlorophyll content variation which was heavily dependent on fertilizer. Yield per vine and yield per ha have recorded variations depending on climatic condition and fertilizer, but were more stable with calcium supplement. Based on the PCA analysis, trial data were arranged into two groups (G₁ with the variants V₂, V₄ and V₆, and G₂ with the variants V₃, V₅ and V₇). The main factor generating variation between the two groups was the supplementary treatment with calcium associated to the group G₂. Grouping trial variants based on Euclidean distances were highly safe, the value of the cophenetic coefficient being 0.940.