Smart Net-Zero

Introduction: Conventional urea is widely used because of its high nitrogen content and low cost, but substantial nitrogen can be lost through ammonia (NH₃-N) volatilization, reducing fertilizer effi ciency and increasing environmental impacts. This three-year field study evaluated whether en hanced-efficiency fertilizers—NBPT + Duromide-treated urea and slow-release urea-formalde hyde—could reduce NH₃-N losses and CO₂ emissions compared with conventional urea in a sandy soil integrated crop–livestock system (ICLS) in Brazil.

Key findings: Conventional urea produced the highest NH₃-N losses, reaching up to 33% of applied N. Urea-formaldehyde showed the most consistent performance, reducing NH₃-N losses by approx imately 45–57% across the three years and CO₂ emissions by up to 8% compared with conventional urea. NBPT + Duromide initially reduced NH₃-N losses by about 52%, but its effectiveness declined substantially over time, indicating that enhanced-efficiency fertilizer performance can vary with en vironmental and management conditions, particularly the presence of crop residues in ICLS.

Figure| Cumulative NH₃-N volatilization from three N fertilizers (UrConv, UrDuromide, and UrFormaldehyde) at 100, 200, and 400 kg N ha⁻¹ during 2020–2022, with corresponding climatic conditions.

Content adapted from Oliveira et al. | Image reproduced from the original article