Sufficiency ranges (sr) and deviation from optimum percentage (dop) references for leaf blade and petiole analysis in ‘Red Grenache’ grapevines

Aim: To obtain specific references for the nutritional diagnosis of ten essential nutrients for leaf blade and petiole of ‘red Grenache’ (Vitis vinifera L.). Methods and results: Leaf blades and petioles from 36 vineyards of ‘red Grenache’ (Vitis vinifera L.) grafted on Richter 110 were collected and analyzed at flowering and veraison between 1992 and 2008. Using the compiled data bank, nutritional references for ten elements (N, P, K, Ca, Mg, Fe, Mn, Zn, Cu and B were calculated. Optimal values were those around the central data (µ ± 0.25σ), while excessive and deficient values were those beyond the tails of the distribution (µ ± 0.84σ). Percentile calculation was performed when transformations to normal distributions became unlikely. Conclusion: References for Sufficiency Ranges (SR) and Deviation from Optimum Percentage (DOP) methods were obtained for those ten nutrients studied. Significance and impact of the study: The proposed ‘red Grenache’ references for leaf blade and petiole contribute to the improvement of the accuracy of ‘red Grenache’ grapevine nutrient diagnosis based on tissue analysis. These references are a guide to assess the nutritional status of ‘red Grenache’ grapevine around the world in general and, with higher accuracy, for the Rioja region and areas with similar vineyard conditions