Norma DRIS e diagnóstico de fertilidade do solo para milho no nordeste baiano

Abstract

The establishment of regional DRIS norms for maize is an effective instrument for diagnosing nutritional balance in maize, as it supports decision-making regarding fertilization management and productivity maximization. The objective of this study was to establish a regional DRIS norm for maize, based on DRIS calculations derived from soil analysis attributes in commercial fields in the northeastern region of Bahia. The study was conducted using 140 soil analyses from 140 commercial fields distributed across the municipalities of Inhambupe, Itapicuru, Olindina, Aporá, Água Fria, and Euclides da Cunha, Bahia, under plant populations ranging from 50,000 to 60,000 plants ha−1. The database was initially divided into two groups with the same hybrid, corresponding to high and low productivity levels, adopting 9.3 t ha−1 as the cutoff value for the hybrid P3707 VYH (Pioneer®). Subsequently, the lower productivity group was subdivided into four subgroups: subgroup A (8.7 and 9.0 t ha−1), subgroup B (8.1 and 8.4 t ha−1), subgroup C (7.8 t ha−1), and subgroup D (< 7.5 t ha−1). The norm was established by calculating the ratios among the parameters of the reference group. The results revealed high variability in micronutrients, especially Mn, Zn, and Cu, as well as imbalances associated with excess K, Mg, and Cu and Ca deficiency. The groups exhibited distinct nutritional patterns, with subgroups A and D showing the highest Nutritional Balance Index (NBI) values, indicating greater imbalance, whereas subgroup B presented greater equilibrium. The application of the fertilizer response potential method confirmed calcium as the main limiting nutrient in subgroup A. Therefore, the adoption of regionalized DRIS norms proved essential for more accurate diagnoses and for guiding more efficient soil fertility management practices.