Nitrogen (N) loss through ammonia (NH₃) volatilization (AV) has been a major agricultural and environmental concern. AV reduction is one of the main challenges to increase N-use efficiency and decrease environmental risks. The present research aimed to evaluate the effects of the addition of urea (URE) amended with compost (COM) and biochar (BC) to soil on the biochemical process of AV and the soil-urea microsite bacterial community composition. Soil microcosm assays were performed with the addition of URE, COM, and BC and their combination URE-COM and URE-BC under incubation conditions for 28 days. AV decreased significantly only in the URE-BC, reducing the N loss by approximately 40% compared to that in the URE. The results revealed that URE hydrolysis occurred within 5 days of incubation, and urease activity increased in all treatments with urea. Urease activity decreased significantly in the URE-COM and URE-BC. Bacterial 16S rRNA gene sequencing revealed a high abundance of reads classified to Sporosarcina, suggesting that organisms belonging to this genus might play an important ecological role in the soil-urea environmental niche. There was no effect of the COM or BC on the abundance of this genus or on the bacterial community composition at 5 and 28 days. This study shows that the addition of an acidic biochar amendment with urea is the key pathway to reduce N loss through AV.

氮 (N) 通过氨损失 (NH ₃) 挥发 (AV) 一直是一个主要的农业和环境问题。减少 AV 是提高氮利用效率和降低环境风险的主要挑战之一。本研究旨在评估向土壤中添加经堆肥 (COM) 和生物炭 (BC) 改良的尿素 (URE) 对 AV 的生化过程和土壤-尿素微生物群落组成的影响。土壤微观世界分析是通过添加 URE、COM 和 BC 以及它们的组合 URE-COM 和 URE-BC 在孵育条件下进行 28 天。仅在 URE-BC 中 AV 显着降低，与 URE 相比，N 损失减少了约 40%。结果表明，URE 水解发生在孵育的 5 天内，并且在所有尿素处理中脲酶活性均增加。URE-COM 和 URE-BC 中的脲酶活性显着降低。细菌 16S rRNA 基因测序显示高丰度的 reads 被归类为Sporosarcina，表明属于该属的生物可能在土壤 - 尿素环境生态位中发挥重要的生态作用。在第 5 天和第 28 天，COM 或 BC 对该属的丰度或细菌群落组成没有影响。该研究表明，添加尿素酸性生物炭改良剂是减少 AV 造成的氮损失的关键途径。