The potential of high spatial resolution information to define within-vineyard zones related to vine water status

Abstract

Abstract. The goal of this study was to test the usefulness of high-spatial resolution information provided by airborne imagery and soil electrical properties to define plant water restriction zones within-vineyards. The main contribution of this is to propose a study on a large area representing the regions' vineyard diversity (different age, different varieties and different soils) located in southern France (Languedoc-Roussillon region, France). Nine non-irrigated plots were selected for this work in 2006 and 2007. In each plot, different zones were defined using the high-spatial resolution (1m 2 ) information provided by airborne imagery (Normalised Difference Vegetation Index, NDVI). Within each zone, measurements were conducted to assess: (i) vine water status (Pre-dawn Leaf Water Potential, PLWP), (ii) vine vegetative expression (vine trunk circumference and canopy area), (iii) soil electrical resistivity and, (iv) harvest quantity and quality. Large differences were observed for vegetative expression, yield and plant water status between the individual NDVI-defined zones. Significant differences were also observed for soil resistivity and vine trunk circumference, suggesting the temporal stability of the zoning and its relevance to defining vine water status zones. The NDVI zoning could not be related to the observed differences in quality, thus showing the limitations in using this approach to assess grape quality under non-irrigated conditions. The paper concludes with the approach that is currently being considered: using NDVI zones (corresponding to plant water restriction zones) in association with soil electrical resistivity and plant water status measurements to provide an assessment of the spatial variability of grape production at harvest.

Are precision agriculture tools and methods relevant at the whole-vineyard scale?

“…This result is in agreement with experiments carried out under similar conditions in terms of significant water restriction (Acevedo-Opazo et al, 2008a, Ojeda et al, 2005. Lack of correspondence between berry composition and zoning is due to the complexity of the processes that affect berry composition: despite the zoning proposed in this study indirectly integrates some the factors that affect berry composition (shoot growth, water status, nitrogen level), it does not take into account some other factors, such as fruit load, that also affect berry composition (Keller et al, 2008).…”

“…Assuming temporal stability of the spatial variability of vigour (Tisseyre et al, 2008), the image of 2007 was used to define the sampling of additional data, whereas the image of 2008 was used for the analysis of these additional data in relation to NDVI values (see next sections). The 30 cm image pixels were aggregated into 3 m pixels, which approximates the "mixed pixel" row spacing approach of Lamb et al, (2004), using the methodology outlined in Acevedo-Opazo et al (2008a).…”

“…Since the earliest studies in the 1990s, there have been significant improvements in both the spatial resolution of remotely obtained information, currently of the order of centimetres (Hall et al, 2010) and in the mathematical analyses performed with the information acquired (Pedroso et al, 2010, Paoli et al, 2007. To date, precision agriculture tools and methods have been mainly applied at the field level, and much research has highlighted the ability of high resolution data to match within field variability at this scale (Acevedo-Opazo et al, 2008a, Acevedo-Opazo et al, 2008b, and the potential benefits of its management according to the obtained zoning , Taylor, 2004, Arnó et al, 2009. The field level corresponds to a production unit that has the same age, variety and rootstock, and is usually managed uniformly in terms of fertilization, pruning, irrigation, etc.…”

Benefit of ancillary data acquired at the cooperative level to study soil type and climatic zone influence on berry composition: a case study in Rioja appellation

“…Images were corrected for camera-induced geometric and radiometric distortions (Lamb et al, 2004). Image rectification (assigning map coordinates to individual image pixels), following the methodology proposed by Acevedo-Opazo et al (2008) was then completed using 16 ground control points. These points were readily identifiable features, of known dGPS coordinates, in the images, consisting of ends of selected vine rows.…”

Vineyard Detection and Vine Variety Discrimination from Very High Resolution Satellite Data

“…In particular, apart from the within-field crop analysis and the estimation of the spatial variability in wine-grape composition and yield [17][18][19][20][21][22][23], there is plenty of research towards the classification, identification and delineation of crops in remote sensing data [24][25][26][27]. However, despite recent research efforts towards the detection and delineation on medium [28][29][30] and high resolution [31,32] spatial scales, the development and validation of efficient classification frameworks for operational vineyard detection in high resolution data and over large agricultural regions still remain a challenge.…”