Development and Yield of Irrigated Sugarcane as Affected by Nitrogen Sources and Rate in Brazilian Cerrado Oxisol

Sugarcane is the most promising crop among renewable biofuels producers and one of the countries that produces the most green matter per unit area, whose greater limitations to productivity are mainly related to the adequate availability of water and mineral nutrients, in particular nitrogen (N). Based on the hypothesis that the source and the availability of nitrogen influence the growth, development and yield of irrigated sugarcane in the cerrado region. The objective of this study was evaluate the biometric variables and yield of irrigated sugarcane, in the cane-plant cycle, as affected by source and nitrogen rate. The soil utilized was an Oxisol (Rhodic Hapludox), cerrado (savannah) phase. The experiment was carried out at Farm of the Raízen Mill, located in the municipality of Jataí, Goias State, Brazil. The variety IACSP95-5000 was used in a randomized block design, analyzed in a split-split-plot scheme, with three replicates. The treatments were four N rates (0, 60, 120 and 180 kg ha-1); two fertilizer sources (urea and ammonium nitrate). The factors evaluated were in the plots of four doses of N (0, 60, 120 and 180 kg ha-1). In the subplot two sources of N (urea and ammonium nitrate) and as sub-subplot were represented by four evaluation periods (210, 250, 290 and 330 days after the planting-DAP). The irrigation was by sprinkling, in a central pivot. The evaluated variables were: plant height, stalk diameter, total number of leaf, leaf area, number of industrializable tillers, stalk yield, pointer yield and total recoverable sugars. The highest stalk yield, pointer yield and total recoverable sugars occurred at the average dose of 143.61 kg ha-1 of N, with an average increase of 25.87%.