What to Choose? Mineral or Organic Nitrogen to Improve Sugarcane Yield Parameters?
摘要
The adoption of sustainable practices, including the rational application of nitrogen (N) fertilizers, is increasingly encouraged in sugarcane cultivation due to the high cost of mineral fertilizers. An eminent alternative is the use of poultry litter, a readily available nitrogen source. This study tested the hypothesis that poultry litter, as an organic nitrogen source (ON), can meet the N requirements of sugarcane, either as a substitute for or in combination with a mineral nitrogen source (ammonium nitrate, MN). The effects of varying ON application rates (0, 2, 4, 6, and 8 t ha−1) and MN rates (0, 40, 80, 120, and 160 kg ha−1), as well as their interaction, were evaluated over two crop seasons. The study analyzed N, P, and K contents, technological quality, and sugar production in the stalks. Results confirmed that poultry litter can replace ammonium nitrate for supplying N, P, and K to sugarcane. However, higher rates of ON and MN negatively impacted juice quality parameters, including °Brix, apparent sucrose content (POL), and purity. Excessive ON-MN combinations also reduced total sugar recovery. A balanced application of 4.2 t ha−1 of ON combined with 120 kg ha−1 of MN resulted in the highest sugar yield, averaging 22.845 t ha−1. While combining ON and MN can optimize sugar yields, excessive N application—whether organic or mineral—diminishes juice quality by reducing sucrose content.