Phenological Stage and Tissue Type of Grapevines Affect Concentrations and Variability of Mineral Nutrients

Background and goals There is currently no consensus on the ideal tissue type or on the ideal phenological stage at which to sample grapevine mineral nutrients. The goal of this study was to assess the concentrations and variability of nutrients in leaf blades and petioles during differing phenological stages and in different vineyards.

Methods and key findings The study was conducted in the Finger Lakes region of New York State. Multivariate analysis showed that phenology, tissue type, vineyard site, and year all influence vine nutrient status. Tissue type accounted for more than twice the proportion of variance within the model than site, even though these vineyards consisted of different soil types, ages, rootstocks, and training systems. Within tissue type, leaf blade samples had lower variability than petioles; petiole samples had 30% greater variability in nutrient concentrations than leaf blades. Tissue samples taken at bloom had 66% greater variability than those sampled at veraison.

Conclusions and significance The differences in nutrient concentrations among different tissue types and phenological time points underscore the importance of basing recommended nutrient concentrations on specific tissue types and time points. We concluded that nutrient recommendations should be developed based on leaf blade samples to assess vine nutrient status more precisely. Sampling tissue at veraison provided samples with lower variability. However, logistical considerations such as obtaining grapevine nutrient reports with sufficient time to address deficiencies within the current growing season, may be of greater importance to growers. The results within this study may be region- and/or cultivar-specific.