Identifying irrigation zones across a 7.5-ha 'Pinot noir' vineyard based on the variability of vine water status and multispectral images. (Special Issue: Advances in site-specific irrigation management and grapevine water requirements.)

摘要

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 identifying zones of similar yield within a 7.5-ha 'Pinot noir' vineyard. The two methods were based on: spatial distribution of average midday leaf water potential ( Psi _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 Psi _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 Psi _L and yield. The Psi _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 Psi _L when RDI is applied.