The objective of this work was to model DRIS functions and k factor on foliar diagnosis of mango crops. Ten commercial orchards, at yield stage, in the São Francisco River valley were monitored, monthly, during a two-year period, by means of collecting leaf samples to determine N, P, K, Ca, Mg, B, Fe, Mn, Zn and Cu concentrations. Data were tested for normality and bivariate relationships between nutrient concentrations were used to calculate DRIS norms. Mean, variance as well as minimum and maximum values were calculated for each relationship within the population. Nutrients were classified as follows: highly responsive macronutrients (HRMa) (N, P and K); rarely responsive macronutrients (RRMa) (Ca and Mg); highly responsive micronutrients (HRMi) (B, Fe, Mn and Zn), and rarely responsive micronutrients (RRMi) (Cu). DRIS functions were developed for each nutrient class. Results showed that the developed model expresses the nutritional balance adjusted for each nutrient, and reflects the expected biological behavior of plants as a result of variation in the availability of nutrients.
Mangifera indica; DRIS norms; foliar diagnosis
