Uso do DRIS na avaliação do estado nutricional da cana-de-açúcar

Abstract

The objective of this work had established DRIS norms for sugarcane crop in different yields levels. Results of the chemical analysis of leaves for N, P, K, Ca, Mg, S, B, Cu, Fe, Mn and Zn was used, with your respective yield of 78 commercial fileds collected in Cocal usin, in Paraguaçu Paulista, São Paulo state, Brazil, between October and November of 2007. For the database formation to divided in six yield levels, of 100, 110, 120, 130, 140 and 150 Mg ha-1, with the establishment of all the binary relationships among the nutrients studied, then calculated the average, the standard deviation and the variance for each nutrient concentration, as well as for the relationships among these, in each sub-population, being maintained 55 relationships, the ones that presented the largest reason in the variance among the sub-populations. It was calculated the index of each nutrients, IBN of each population and the potential of answer to nutrient application. There were found significant differences between the nutrients contents and the yields to different varieties, being RB 935744 the most productive. The binary relationships among nutrients presented different values in populations studied. The yield level of 140 Mg ha-1 presented higher correlation between IBN and the productivity, being selected for DRIS norms definition. The nutrient order to nutrient supply was: B>Mn>Cu>S.