DRIS NORMS AND CRITICAL LEAF NUTRIENT LEVELS FOR ‘NIAGARA ROSADA’ GRAPE IN JUNDIAÍ REGION, SÃO PAULO (BRASIL)

ABSTRACTPreliminary Diagnosis and Recommendation Integrated System (DRIS) norms and critical leaf nutrient levels (CLN) for ‘Niagara Rosada’ grape grafted on the rootstock ‘IAC 766’ growing in the region of Jundiaí, State of São Paulo (Brazil) are presented. DRIS norms and CLN were established from a data bank of leaf nutrient concentration(N, P, K, Ca and Mg) and fruit yield with 116 records. The data bank gets information from fertilizationexperiments and from a field survey comprising four crop cycles. The data were divided into high-yielding (>26 t/ha) and low-yielding (<26 t/ha) subpopulations and norms were computed using standard DRIS procedures. Even with the diversity of cropping conditions, the relationship between the nutrient balance index from DRIS and fruit yield was highly significant (R2 = 0.48, p<0.0001), indicating that part of the variation in productivity of vineyards can be credited to nutritional status of the plants. The CLNs were derived using multiple linear regressions relating to the foliar nutrient concentration with DRIS indices of all nutrients. The CLNs for N, P, K, Ca, and Mg were 38.0, 3.0, 11.4, 13.7, and 3.5 g/ kg, respectively.