An experimental design applied to vineyards for identifying spatially and temporally variable crop parameters

Abstract

Harvesting uniform batches of grapes is required to optimize must quality as one prerequisite for premium wine production. The definition of sub-units of vineyards based on within-field variation allows unitbased vineyard management during cultivation and harvest. Essential for such vineyard management is the definition of sub-units that correspond with uniform batches of quality parameters of the fruit (e.g. berry residual sugar, anthocyanin content) at harvest time or with physiological parameters measuring the vine during berry development until ripeness. The definition requires geo-referenced sampling and parameter analysis, usually in combination with interpolation and kriging methods employed to describe spatial vineyard variation.
In an attempt to develop an assay for within-variation in vineyards physiological parameters assessed through chlorophyll fluorescence measurements and leaf temperature were assessed at bloom, veraison and post veraison in a randomized block design in two vineyards of Lower Austria. A statistical model based on a repeated measurement ANOVA was developed and showed suitability for the detection and monitoring of vineyard variability throughout the vegetation period based on the maximum quantum yield of photosystem II (Fv/Fm), the maximum leaf temperature (maxT_leaf) and malic acid. These parameters allow the prospective classification of sub-units according to the vine’s vitality and may be adopted for scientific experimentation and for practical viticulture.