Analysis of vineyard differential management zones and relation to vine development, grape maturity and quality

J A Martinez-Casasnovas,M C Ramos,J Agelet-Fernandez,J Arno

doi:10.5424/sjar/2012102-370-11

Abstract

The objective of research was to analyse the potential of Normalized Difference Vegetation Index (NDVI) maps from satellite images, yield maps and grapevine fertility and load variables to delineate zones with different wine grape properties for selective harvesting. Two vineyard blocks located in NE Spain (Cabernet Sauvignon and Syrah) were analysed. The NDVI was computed from a Quickbird-2 multi-spectral image at veraison (July 2005). Yield data was acquired by means of a yield monitor during September 2005. Other variables, such as the number of buds, number of shoots, number of wine grape clusters and weight of 100 berries were sampled in a 10 rows × 5 vines pattern and used as input variables, in combination with the NDVI, to define the clusters as alternative to yield maps. Two days prior to the harvesting, grape samples were taken. The analysed variables were probable alcoholic degree, pH of the juice, total acidity, total phenolics, colour, anthocyanins and tannins. The input variables, alone or in combination, were clustered (2 and 3 Clusters) by using the ISODATA algorithm, and an analysis of variance and a multiple rang test were performed. The results show that the zones derived from the NDVI maps are more effective to differentiate grape maturity and quality variables than the zones derived from the yield maps. The inclusion of other grapevine fertility and load variables did not improve the results.

Highlights

Vineyard variability is a known phenomenon of which viticulturists are generally aware, understanding that vine performance varies within their vineyards (Bramley & Hamilton, 2004; Bramley et al, 2011)
Yield is the variable with the highest coefficients of variation (30.1 and 32.2%, respectively), which indicate a potential for Precision Viticulture (PV) applications as zonal management or selective harvesting (Bramley & Hamilton, 2004)
The values of the basic statistics of the sampled variables are within the range of variability found by Bramley (2005) in Cabernet varieties in Australia, who observed more homogeneity in properties as probable alcoholic degree or pH than acidity, colour or phenolics content

Summary

Introduction

Vineyard variability is a known phenomenon of which viticulturists are generally aware, understanding that vine performance varies within their vineyards (Bramley & Hamilton, 2004; Bramley et al, 2011). The development of the spatial information technologies tools in the last decades and the advent of grape yield sensors and monitors has allowed obtaining information on vine performance as well as soil variability across the vineyard fields (Proffitt & Malcolm, 2005; Proffitt et al, 2006). Selective harvesting only based on intrafield yield variability may not correspond with wine grapes of significant different qualities (Hall et al, 2003). This makes interesting to analyse relationships between wine grape quality properties and other spatial variables that could influence grape yield and quality, helping in the delineation of management zones

Methods

Results

Conclusion