Fluxo de óxido nitroso e amônia na cultura do milho (Zea mays) em função de fontes de nitrogênio

Abstract

Nitrogen (N) is the most demanded essential nutrient for agricultural production, especially in corn cultivation, being crucial for productivity but also the most susceptible to significant losses. These losses mainly occur through nitrate leaching (NO₃⁻), ammonia volatilization (NH₃), and nitrous oxide (N₂O) emissions, one of the main greenhouse gases (GHG). To mitigate these impacts, the agricultural sector relies on enhanced efficiency nitrogen fertilizers, developed to reduce N losses and increase productivity with lower environmental impact. This study aimed to evaluate different nitrogen sources applied to the surface in corn cultivation, comparing nitrous oxide and ammonia losses with regular urea. The experiment was conducted on a very clayey Red Latosol in Francisco Beltrão, PR, Brazil. The experimental design was a randomized block design with four replicates and five treatments: i) NA (100% N); ii) NA (70% N); iii) regular urea; iv) regular urea with NBPT inhibitor; and v) control (no N application). N losses through NH₃ volatilization and N₂O emissions were analyzed. Gas emissions were monitored using closed static chambers, with samples collected during crop development. The statistical analysis of the data was performed using analysis of variance, and means were compared by Tukey's test at a 5% significance level. Urea + NBPT and ammonium nitrate did not show significant differences in N₂O emissions compared to common urea, but were effective in reducing NH₃ volatilization, with losses of less than 2%, while common urea reached 12% of the total N applied. The N2O emission factor was lower than that proposed by the IPCC, indicating the importance of having regionalized studies.