Effects of the Annual Nitrogen Fertilization Rate on Vine Performance and Grape Quality for Winemaking: Insights from a Meta-Analysis

Figure 4

Contour plots of the density surfaces in Figure 3 and the corresponding Mitscherlich law fitted to the ridgeline points where fitting leads to reasonable results. The fitting was obtained by density-weighted generalized reduced gradient (GRG) nonlinear optimization of the sum of squared deviations between calculations and observations of the trial-normalized vine production parameters. (a) Grape yield. (b) Pruning weight. (c) Bunch number. (d) Bunch weight. (e) Berry number. (f) Berry weight.

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(b)

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