Industrial Quality of Sugarcane Under Fertigation with Nitrogen and Zinc

Both the excess and deficiency of nutrients in the soil can influence the technological quality of sugarcane stalks, and affect the quality of the juice, the fiber content, and the concentration of sucrose, which directly impact the quality and quantity of products derived from sugarcane. Thus, this study aimed to investigate the effect of nitrogen and zinc fertigation, irrigated by a central pivot, on various parameters that affect the industrial quality of sugarcane (IACSP 95-5000), in the plant and first ratoon crop cycles in a Cerrado Red Latosol soil in Brazil. The experiment was conducted under field conditions at an average altitude of 907 m in an area of the Rio Paraiso II farm of the Raizen Mill, in the municipality of Jatai, Goias (GO). The experiment was conducted in a randomized complete blocks design and analyzed in a scheme of 4 × 5 subdivided plots, with three repetitions. The treatments consisted of four nitrogen doses (0, 60, 120, and 180 kg ha−1) and five zinc doses (0, 2.5, 5.0, 7.5, and 10.0 kg ha−1), on plant cane and first ratoon cane. Urea served as the source of nitrogen fertilizer and was applied in three dosages (treatments) 60 days after planting. Zn sulfate served as the zinc source and was applied in four dosages (treatments) at a single time in the planting. At harvest, ten stalks were randomly sampled from each plot and sent to the Raizen Mill agro-industrial laboratory in Jatai-GO for analysis and to determine the polarizable amount of sugar per cane (Pol % cane), polarizable amount of sugar in the juice (Pol % juice), total soluble solids (Brix %), apparent purity, wet bagasse weight (WBW), reducing sugars, total recoverable sugar (TRS), and fiber content. The highest doses of zinc (10 kg ha−1) and nitrogen (180 kg ha−1) had the greatest effects on sugarcane WBW and TRS.