Whithin-field temporal stability of some parameters in Viticulture: potential toward a site specific management

Abstract

Aims: The goal of this paper is to present the results of a study run over 7 consecutive years which aims at characterising the Temporal Stability of Within-Field Variability (TSWFV) for the most routinely measured vine parameters. In the context of precision viticulture TSWFV is of importance to know whether or not it is relevant to use the within-field variability of the year « n » to design a site-specific management strategy for the year « n+1 ».

Methods and results: The experiment was based on 6 vine parameters measured at 30 sites located within a non-irrigated vineyard block. Parameters measured included indicators of a vine capacity to produce biomass (pruning weight, yield and size of the canopy) as well as indicators of harvest quality (sugar content, pH and Total Titrable Acidity). For each parameter a significant temporal variability of the field average was observed from one year to another. This temporal variability led us to define the TSWFV as the occurrence of consistently high value or low value zones within the field. The definition of high and low values is done according to the average field value of the year for each parameter.

Conclusion: TSWFV analysis allows the parameters to be classified into two distinct types. Type 1 parameters (pruning weight, yield and canopy size) which present a significant TSWFV and type 2 parameters (sugar, Total Titrable Acidity and pH) which present no TSWFV.

Significance and impact of study: For precision viticulture management these results are significant. They show that yield or vigour (pruning weight, size of the canopy) maps of the previous years are relevant in designing site-specific management strategies in the year « n+1 » or subsequent years. Conversely, maps of quality parameters from previous years are not useful in determining how to manage harvest quality in the year « n+1 ».