Crescimento e produtividade da cana-de-açúcar submetida a doses de nitrogênio

Abstract

Due to the economic importance the sugarcane agroindustry there has been an interest in the investigation of variables that allow achieving the “maximum efficiency the fertilization”, especially nitrogen fertilizer utilization for the culture to gaining high productivity and reduction in N. This study aimed to assess the growth and productivity cane sugar subjected to increasing doses of nitrogen. The work was developed in the farm Flor da Ribeira, Lot 01, in sugarcane plant Sumaúma, localized in the municipality of Marechal Deodoro in the state of Alagoas. The variety used was the planted RB92579 on 30 January 2012 in combined spacing (1.50 x 0.90). The study was divided into five treatments with four replications, and the study design was randomized blocks where been applied five N rates (0, 30, 60, 90 and 120 kg ha-1) in the shape of urea. At 60, 90 and 120 DAP was held counting the number of tillers and 240 DAP measurement of height, culm diameter, reading using the SPAD-502 leaf collection and +3 for leaf analysis. Was estimated production in tons per hectare (TCH and TPH) and was cleaned the characterization of technological quality of sugar cane where was obtained the data from Brix, PC, fiber, purity and ATR. Data were subjected to analysis of variance and F test through of the statistical program SAEG 5.0. For parameters that showed statistical difference was applied regression and the results were presented in graphical form. Nitrogen fertilization did not influence the number of tillers per meter, height and culm diameter at the plant cane cycle; promoted increases foliar N resulting in na increase in chlorophyll content in the leaf +3; Use of the SPAD is an efficient technique for indirect determination of N once the readings show a strong correlation positive with the content in the leaves of cane sugar and can serve as a reference for recommending N fertilization.Nitrogen fertilization at planting potentiated the TATRH, TCH and TPH in the plant cane cycle elevating the productivity of sugarcane field, the higher dose of N applied was not sufficient to achieve maximum peaks of TCH and TPH showing possibility of response to higher doses ; the practice of nitrogen fertilization should be adopted in the management of plant cane, it provides a greater economic return of the crop increasing the profitability of sugarcane plantation.