New trends in sugarcane fertilization: Implications for NH₃ volatilization, N₂O emissions and crop yields

Area of Science:

• Agricultural Science
• Environmental Science
• Soil Science

Background:

• Nutrient recycling in agriculture reduces environmental impact and climate change effects.
• Organo-mineral formulations combining concentrated vinasse (CV) with fertilizers are emerging in sugarcane cultivation for improved logistics and cost reduction.
• The environmental implications of these novel formulations on sugarcane fields require thorough investigation.

Purpose of the Study:

• To evaluate the effects of an organo-mineral formulation (CV + granular urea (UR)) with and without a nitrification inhibitor (NI) on sugarcane yield, NH3 volatilization, and N2O emissions.
• To compare the performance of the organo-mineral formulation against conventional urea fertilization.
• To assess the efficacy of nitrification inhibitors in mitigating greenhouse gas emissions from this fertilization strategy.

Main Methods:

• Field experiments conducted over two fertilization seasons (dry and wet).
• Treatments included control, UR, UR + NI, CV, CV + UR, and CV + UR + NI, with CV applied at 7 m³ ha⁻¹.
• All treatments (except control and CV) were balanced for Nitrogen (N) and Potassium (K) content.
• Measurements focused on crop yield, NH3 volatilization, and N2O emissions.

Main Results:

• The organo-mineral formulation (CV + UR) significantly decreased NH3 volatilization compared to UR alone (from 7% to 4% in dry season, 3.5% to 0.5% in wet season).
• N2O emissions increased with CV + UR in the wet season (1% to 2% of applied N) but not in the dry season.
• Nitrification inhibitors (NI) effectively reduced N2O emissions by 43–48% (dry season) and 71–84% (wet season).
• Sugarcane yield was positively influenced by UR or the organo-mineral formulation only in the dry season, with CV + UR yielding the highest.
• Emission intensities (kg CO2eq Mg⁻¹ of stalk) were generally highest for CV + UR.

Conclusions:

• The organo-mineral formulation effectively reduced NH3 losses but led to increased N2O emissions compared to standard urea fertilizer.
• Nitrification inhibitors proved effective in mitigating N2O emissions from the organo-mineral formulation in both dry and wet seasons.
• The organo-mineral formulation shows potential for improving sugarcane yield, particularly in dry conditions, while managing nitrogen losses requires further optimization, possibly through nitrification inhibitors.