ORIGINAL PAPER Identifying irrigation zones across a 7.5-ha ‘Pinot noir’ vineyard based on the variability of vine water status and multispectral images J. Bellvert • J. Marsal • M. Mata • J. Girona Received: 12 August 2011 / Accepted: 4 January 2012 / Published online: 23 August 2012 Ó Springer-Verlag 2012 Abstract Vine water status, yield and berry composition are variables within a vineyard. There is current interest in defining zones of similar yield and berry composition. The aim of this study was to compare two methods for identi- fying zones of similar yield within a 7.5-ha ‘Pinot noir’ vineyard. The two methods were based on: spatial distri- bution of average midday leaf water potential (W L ) and plant cell density (PCD = near-infrared/red) which is a vegetation index. A proposal for splitting the vineyard into eight new irrigation zones was assessed. A ‘blind’ zonation based on regular polygons of equal sizes was also established as a standard for comparison. Coefficients of variation (C v ) in yield for both methods were compared with that of the blind zonation. In 2006 and 2007, a k-means cluster analysis indicated that variability in W L was mainly effected by soil properties. In both years, the vineyard was fully irrigated (100 % ET c ). The two methods did not improve yield C v for full irrigation in 2006 and 2007 compared to blind zonation. In 2009, regulated deficit irrigation (RDI) was applied resulting in higher variability in W L and yield. The W L method of zonation significantly reduced coefficient of variation under RDI but PCD method did not despite the reduction in C v by 16.7 %. We recommend irrigation zonation based on W L when RDI is applied. Introduction In semi-arid regions of the Mediterranean basin, efficient irrigation management is necessary to obtain high-quality grapes. There is current interest in obtaining homogeneity in terms of yield and berry composition within vineyards. Grapevine water status has a direct effect on yield (e.g. Intrigliolo and Castel 2009) and on berry composition (e.g. Basile et al. 2011) but soil physical properties are deemed as being foremost important in causing spatial variability. Soil properties may influence grapevine water status if irrigation requirements are not met. Differences in yield (Bramley and Hamilton 2004) and berry composition (Bramley 2005) have been reported across irrigated vineyards. Variability in canopy vigour, yield and fruit composition within a vineyard can be the result of grapevines responding differently to the same irrigation protocol across different vineyard zones. Designing an irrigation system without taking into account spatial variability of the soil and plant water status can potentially increase variability in yield and berry composi- tion across a vineyard. A widespread problem in many vineyards is that awareness of the faulty irrigation design happens after the system is set up. The problem of variability within a vineyard has sometimes been addressed by splitting the block into sev- eral individual plots and treating each plot as a single management unit for cultivation and harvest (Bramley and Lamb 2003; Bramley and Hamilton 2004; Johnson et al. 2001). Another approach is applying different irrigation amounts in various zones of a vineyard. For instance, Proffitt and Malcolm (2005) managed irrigation in vigorous areas differently from less vigorous areas in order to reduce vegetative growth in the former. Information about the causes of spatial vineyard variability was provided by Ortega et al. (2003) and Taylor et al. (2005). But Communicated by V. Sadras. J. Bellvert  J. Marsal  M. Mata  J. Girona (&) Irrigation Technology, Institut de Recerca i Tecnologia Agroalimenta `ries (IRTA), Centre UdL-IRTA, 191 Av. Rovira Roure, 25198 Lleida, Spain e-mail: joan.girona@irta.es 123 Irrig Sci (2012) 30:499–509 DOI 10.1007/s00271-012-0380-y