DRIS NORMS INTERPRETATION FOR PLANT TISSUE AND SOIL FOR "PÊRA" ORANGE IN THE GOIÁS STATE CENTRAL REGION

Abstract

The Diagnosis and Recommendation Integrated System (DRIS) is a method based on the average relations among nutrients and the respective variation coefficients, in a high yield population, establishing the DRIS norms. The study aimed to generate DRIS norms for nutritional diagnosis of the orange tree [Citrus sinensis (L.) Osbeck] cv. Pêra, grafted on Clove lemon tree, on the cerrado area, in the central region of Goiás State, Brazil. Leaf samples on fruit-bearing branches and soil samples were collected and the yield was estimated in commercial orchards at Inhumas, Goiânia, and Goianápolis municipalities, during the 2004/2005 growing season. The databank was made up of 303 analysis, where the proportion of N, P, K, Ca, Mg, S, Cu, Fe, Mn, Zn, and B was analyzed, in the leaves, and OM, P, K, Ca, Mg, S, Cu, Fe, Mn, Zn, and B in the soil. The norms were generated from a reference population with fruit yield above 22 t ha-1, and were compared with those available in the specialized literature. It was concluded that the DRIS norms for the region are different from those obtained for other sites. The results also showed that it is important the development of regional norms, instead of their universalization, for DRIS application.

KEY-WORDS: Orange tree; DRIS norms; nutritional balance.