Root detritusphere is one of the most important sources of N₂O, however, understanding of how N₂O emission from the detritusphere is influenced by soil properties remains elusive. Here, we evaluated the effects of pore architecture and soil moisture on N₂O emission during the decomposition of in-situ grown roots of switchgrass, an important bioenergy crop. We combined dual isotope labeling (¹⁵C and ¹⁵N) with zymography to gain insights into the location of the microbial N₂O production in soils with contrasting pore architectures. In the studied soil, the effect of soil pore architecture on N₂O emissions was 6 times greater than that of soil moisture. Soil dominated by > 30 μm Ø pores (i.e., large-pore soil) had higher chitinase activity than the soil dominated by < 10 μm Ø pores (i.e., small-pore soil), especially near the decomposing roots. The chitinase activity on the decomposing roots was positively correlated with emission of root-derived N₂O, indicating that N released from root decomposition was an important source of N₂O. Greater N₂O and N₂ emission was induced by switchgrass roots in soils dominated by the large- compared to the small-pore soils. The microenvironment developed near decomposing roots of the large-pore soil also resulted in positive N₂O priming. Our study challenged the traditional view on soil moisture as the main factor of N₂O production. Production and emission of N₂O was most intensive in microbial activity hotspots (i.e., rhizosphere legacy) in the large pores, where decomposed roots release mineral N as the main N₂O source.

_{根碎屑层是 N 2} O的最重要来源之一，然而，了解碎屑层的 N ₂ O 排放如何受土壤特性的影响仍然难以理解。在这里，我们评估了重要的生物能源作物柳枝稷原位生长根系分解过程中孔隙结构和土壤水分对 N ₂ O 排放的影响。我们将双同位素标记（¹⁵ C 和¹⁵ N）与酶谱学相结合，以深入了解具有对比孔隙结构的土壤中微生物 N _{2 O 产生的位置。}在研究的土壤中，土壤孔隙结构对 N _2的影响O 排放量是土壤水分排放量的 6 倍。以> 30 μm Ø 孔隙为主的土壤（即大孔隙土壤）比以< 10 μm Ø 孔隙为主的土壤（即小孔隙土壤）具有更高的几丁质酶活性，尤其是在分解根附近。分解根的几丁质酶活性与根源性N 2 O的排放呈正相关，_{表明根分解}释放的N是N 2 O的_重要来源。与小孔隙土壤相比，以大孔隙土壤为主。大孔隙土壤腐烂根部附近形成的微环境也导致N _2为正O 启动。我们的研究挑战了将土壤水分作为 N ₂ O 产生的主要因素的传统观点。_{N 2} O的产生和排放在大孔隙中的微生物活动热点（即根际遗留物）最为密集，其中分解的根释放矿物N 作为主要的N ₂ O 来源。