ADUBAÇÃO SUPLEMENTAR DE NITROGÊNIO NA CULTURA DA CANA DE AÇÚCAR

Abstract

Nitrogen is one of the most required elements in the cultivation of sugarcane, therefore, information on applications via soil and foliar of this nutrient in the culture are discrepant and that is why it is important to study its behavior. Thus, the objective was to evaluate the fertilization of leaf N and via soil in the culture of sugarcane. The experiment was installed at the Araporã Bioenergia S.A plant, at Fazenda Santa Rita. A 5 x 5 factorial scheme was adopted with 4 replications, with 5 doses of ammonium nitrate via soil (0, 50, 100, 150 and 200 kg ha-1) and 5 doses of N Amidic polymer, via leaf (0; 3.3, 6.6, 9.9 and 13.2 L ha-1). The extraction of nutrients by the plant, initial and final total chlorophyll index for the experiment, biometric indexes and industrial quality indexes were analyzed in sugarcane. For statistical analysis of the data, a specific program was used to perform the Shapiro-Wilk W normality test and F test (p <0.05). Afterwards, regression analysis (p <0.05) was performed and the most representative model was selected according to the significance and determination coefficient for the variables that showed difference. Ammonium nitrate doses provided difference for fiber, broth pol extracted, total recoverable sugar, ° brix, magnesium and zinc from sugar cane, however, the doses of leaf polymer did not provide a significant effect on all analyzed characteristics. There was no increase in production variables when the nitrogen supply in the soil was increased, where rainfall variation occurred during the experiment. On the other hand, there was an increase in the levels of zinc in the leaves. There was also an increase in magnesium levels in sugarcane leaves.