DESENVOLVIMENTO, PRODUTIVIDADE E QUALIDADE INDUSTRIAL DA CANA-DE-AÇÚCAR FERTIRRIGADA COM NITROGÊNIO E ZINCO

Abstract

Sugarcane is one of the main Brazilian agricultural crops, evidencing as a culture of great importance to the Brazilian economy, mainly because of the export of sugar, alcohol and energy. The objective of this study was to evaluate the growth and development, stalk productivity, technological quality, yield of sugar and ethanol of sugarcane (IACSP 95- 5000 variety) irrigated by central pivot, submitted to fertirrigation with nitrogen and zinc, in the cane-plant cycle, in Red Oxisol of Cerrado (savannah) phase. The experiment was conducted in field conditions in an area of the Rio Paraiso II Farm belonging to the Raízen industry, in the municipality of Jataí-GO, Brazil. The soil of the experimental area is classified as dystroferric Red Oxisol (Rhodic Hapludox), very clayey, cerrado (savannah) phase. The experimental design used was randomized block, analyzed in split-split-plot 4 x 5 x 4, with three replicates. The treatments consisted of four nitrogen doses (0, 60, 120 and 180 kg ha-1 ) as urea; five doses of zinc (0, 2.5, 5.0, 7.5 and 10 kg ha-1 ) as zinc sulphate; four evaluations times (210, 250, 290 and 330 day after planting - DAP) in sugarcane of first year. The plots consisted of six lines of sugarcane of 5 m long, spaced 1.50 m apart. The area used by plot was two central lines of each plot, disregarding 2 m at each end. The variables evaluated were plant height, stalk diameter, productivity, soluble solids (Brix), bagasse weight (BW), juice reducing sugar (AR%CE), reducing sugar (AR%CA), industrial fiber (FIB), apparent purity (AP), juice apparent sucrose (Pol %juice), apparent sucrose (Pol %cane), total recoverable sugar (TRS), yield of sugar and ethanol. A central pivot realized the irrigation. The application of different doses of nitrogen and zinc by fertirrigation influences the growth and development of sugarcane promoting increases in stalk productivity and technological quality.