Diagnose nutricional e teor de Ca-ligado em mangueira no Submédio do Vale do São Francisco

Abstract

Mango (Mangifera indica L.) is one of the most economically important tropical fruits worldwide, where the São Francisco Valley region in Brazil stands out in the production and export of this product. Fruit quality is an extremely relevant factor, where calcium (Ca) has been synonymous with fruit quality. Efficient nutritional management is essential for maximizing productivity. Diagnostic methods such as the Integrated Diagnosis and Recommendation System (DRIS), modified DRIS (M-DRIS), Nutritional Composition Diagnosis (CND) and mathematical chance, allow diagnosing nutritional imbalances based on the balance of nutrients. The objectives of this work were: a. establish DRIS standards and perform specific nutritional diagnoses for mango cultivars Tommy Atkins, Kent and Keitt and phenological stage, as well as for the set of these cultivars; b. compare the specific DRIS standards for each cultivar and the generic standards established for mango plants in the São Francisco Valley region in the semiarid region of Northeast Brazil. c. establish optimum levels and nutritional ranges by different diagnostic methods and compare them with each other and with the values in the literature; d. identify which diagnostic method was most efficient in determining nutritional imbalances; e. select the nutrients that best respond to the application of the diagnostic method; f. identify the order of hierarchical limitation of nutrients; identify the most limiting nutrients to the production and quality of mango fruits; g. verify the relationship between Ca-bound and the concentration of nutrients in soil, leaf and mango fruits and h. to evaluate the influence of the nutritional status of mango on the Ca-linked concentration. Two studies were carried out. The first study was carried out on seven commercial mango farms in the Middle of São Francisco Valley in the post-harvest and pre-flowering phases. The second study was carried out at two commercial mango farms, located in the municipalities of Cana Nova and Juazeiro, in the São Francisco Valley. Specific DRIS rules for cultivating the phenological phase were established. The DRIS indices, the Nutritional Balance Index, as well as the average Nutritional Balance Index were calculated and the optimal levels and optimal ranges were determined. Subsequently, the nutrients were classified as deficient, balanced or excessive. The levels and optimal ranges established in each phase were compared with each other and with the values recommended in the literature. Subsequently, nutrients were ranked in order of limitation. The correlation between DRIS indexes and productivity per cultivar and phenological phase was evaluated. The concentrations of Ca-linked were correlated with the nutritional contents in the soil, leaf and fruit and the dry matter. The levels of Ca-linked were correlated with the DRIS indices, the IBNm and the values of productivity and dry matter. The use of specific rules for each cultivar was more consistent. The DRIS Beaufils-Maia and M-DRIS Beaulfis-Maia methods were more efficient in nutritional diagnosis. Nutritional diagnoses differed by cultivar and phenological phases. The Ca-linked concentration was positively influenced by the total nutrient content in the fruit. The nutritional balance in the mango leaves was not important for the concentration of Ca-linked in the fruit.