Greenhouse gases (GHGs) emissions from livestock systems are important because of their significant contribution to global warming. Nitrogen fertilization can improve system production; however, it alters soil gas emissions. We evaluated soil nitrous oxide (N₂O), methane (CH₄), and carbon dioxide (CO₂) emissions to investigate how they are affected by increasing levels of N fertilizer (urea) in a productive Marandu grass [Urochloa brizantha (Hochst ex A. Rich) Stapf] pasture subjected to continuous grazing by young Nellore beef cattle (Bos indicus). The N₂O, CH_4, and CO₂ emissions were significantly affected by increasing N fertilizer levels. The seasons also affected GHGs emissions. Nitrogen fertilizer favored CH₄ consumption relative to the control plot without N, with mean emission of 23.7 μg CH₄−C m⁻² h⁻¹ in the fertilized plots compared to 61.6 μg CH₄−C m⁻² h⁻¹ in the control. The N‐fertilized areas presented higher CO₂ emissions compared to the control plot without N. The areas that received N fertilization showed a positive linear association between the water‐filled pore space and N₂O emission. Soil temperature drove CO₂ emissions. Increasing N fertilization in grazed marandu grass increases N₂O and CO₂ emissions during the growing season, while reducing CH₄. The effect of fertilization during the transition season was not apparent, and perhaps other factors could provide a better explanation for the GHG emissions during this period.

中文翻译：

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受氮肥管理影响的热带草原温室气体排放

牲畜系统产生的温室气体排放很重要，因为它们对全球变暖做出了重大贡献。氮肥可提高系统产量；但是，它改变了土壤气体的排放。我们评估了土壤一氧化二氮（N ₂ O），甲烷（CH ₄）和二氧化碳（CO ₂）的排放量，以研究生产性Marandu草[ Urochloa brizantha（Hochst） ex。A. Rich）Stapf]牧场受到内洛尔（Nellore）肉牛犊（Bos indicus）的不断放牧。N ₂ O，CH ₄和CO ₂氮肥水平的提高显着影响了温室气体的排放。季节也影响了温室气体的排放。氮肥青睐CH ₄相对于消耗不具有N-对照区，具有23.7微克CH平均发射₄ -C米^-2 ħ ^-1在相对于61.6微克CH受精重复₄ -C米^-2 ħ ^-1在控制。与没有施氮的对照区相比，施氮的区域呈现出更高的CO ₂排放。施氮的区域显示出充满水的孔隙空间与N ₂ O排放之间呈线性正相关。土壤温度使CO ₂升高排放。放牧的马兰杜草中增加的氮肥在生长季节增加了N ₂ O和CO _2的排放，同时减少了CH ₄。过渡季节施肥的影响尚不明显，也许其他因素可以更好地解释这一时期的温室气体排放。