Normas e funções DRIS para avaliação do estado nutricional do algodoeiro (Gossypium hirsutum r latifolium)

Abstract

With the advent of Diagnose and Recommendation Integrated System (DRIS) by Beaufils (1973), researchers were setting to this system of nutritional diagnosis in order to increase their efficiency. However, evolution has brought a number of possibilities for calculation of DRIS‟ norms and functions, that need to be tested to determine the best combination of methodology. The aim of this work was to study the ways of calculating DRIS‟ norms and functions, in order to obtain the best combination of methodology for the system that seeks greater efficiency in the nutritional diagnosis of cotton crop. The work was conducted an grower´s fields of cotton from 2004 - 2005 crop season, at the South region from Mato Grosso. The database consisted of 108 samples of whole leaf and the yield of seed cotton in the plots of grower´s fields with an average of 100 ha. The F value norms and Jones‟ functions (1981) was the best combination of methodologies, obtaining the best efficiency in nutritional diagnosis. All the methodologies combination were able to diagnose the nutrition state of the cotton crop. Both the norms developed by logarithm function and the choice of relations by F value, may be recommended for assessing the nutritional status of the cotton crop in the south region from state of Mato Grosso, both being effective to diagnose the nutritional status. The two criteria (F value and logarithm function) were effective to diagnose deficiencies and is not diagnostic deficiencies at random, but by the ableness of the method that has been tested by chi-square. The agreement between the methodologies to assess nutritional status was between 92.59 to 100%, except for S which had 74.07% agreement.