ABSTRACT

Emission of nitrous oxide (N₂O) can be reduced using enhanced efficiency nitrogen fertilizers (EEFs), such as urease inhibitors and coating technologies. In this study, we evaluated the potential of EEFs to reduce N₂O emissions in maize in a clayey Inceptisol subjected to no-till management under summer subtropical conditions, in southern Brazil. The EEF sources used included urea containing N-(n-butyl) thiophosphoric triamide (UR-NBPT), polymer-coated urea (UR-pol), in addition common urea (UR), nitrate (CN) and control treatment without the application of nitrogen fertilizer. N₂O emissions were assessed using the static chamber method during one maize season and analyzed through non-linear regression, using a logistic model. The accumulated emission was 0.817, 0.613, 0.457 and 0.393 kg N₂O ha⁻¹, for CN, UR, UR-pol and UR-NBPT, respectively. The maximum daily emission of N₂O did not vary between amidic forms, however for CN it occurred on the 4th day after application (DAA), while for urea forms it occurred on average at 5.3 DAA. The average N₂O emission factor (FE-N₂O) was 0.51%, approximately half the standard factor proposed by the Intergovernmental Panel on Climate Change (IPCC), which is 1%. The application of nitrogen increased the maize yield in relation to the control, but the sources of nitrogen did not differ, with an average yield of 10,455 kg ha⁻¹. Based on our findings, the use of UR-NBPT and UR-pol in subtropical agroecosystems provides environmental benefits, by reducing N₂O emissions in comparison with conventional nitrogen fertilizers (CN and UR), however, the EEFs did not offer agronomic advantages in maize yield.

摘要

使用高效氮肥 (EEF)，例如脲酶抑制剂和涂层技术，可以减少一氧化二氮 (N ₂ O) 的排放。在这项研究中，我们评估了 EEF 在减少巴西南部夏季亚热带条件下免耕管理的粘土 Inceptisol 中玉米中N ₂ O 排放量的潜力。使用的 EEF 来源包括含 N-（正丁基）硫代磷酰三胺 (UR-NBPT) 的尿素、聚合物涂层尿素 (UR-pol)，此外还有普通尿素 (UR)、硝酸盐 (CN) 和未施用的对照处理氮肥。N ₂在一个玉米季节使用静态室方法评估 O 排放，并使用逻辑模型通过非线性回归进行分析。CN、UR、UR-pol 和 UR-NBPT的累积排放量分别为 0.817、0.613、0.457 和 0.393 kg N ₂ O ha ^-1。N ₂ O的最大日排放量在酰胺形式之间没有变化，但是对于 CN，它发生在施用后的第 4 天 (DAA)，而对于尿素形式，它发生在平均 5.3 DAA 时。平均 N ₂ O 排放因子 (FE-N ₂O) 为 0.51%，大约是政府间气候变化专门委员会 (IPCC) 提出的标准系数 1% 的一半。与对照相比，施氮增加了玉米产量，但氮源没有差异，平均产量为10,455 kg ha ^-1。根据我们的研究结果，与传统氮肥（CN 和 UR）相比，在亚热带农业生态系统中使用 UR-NBPT 和 UR-pol 通过减少 N ₂ O 排放来提供环境效益，但是，EEF 在玉米产量。