Earthworms stimulate organic nitrogen (N) mineralization and this is linked to plant N uptake and N loss from soil. Earthworms may also simultaneously transfer N-rich residues into physically protected soil fractions and temporarily increase N stabilization. This study evaluated soil N transformations and lettuce N uptake in soil microcosms amended with ¹⁵N-labeled rice straw, with and without earthworms (Metaphire guillelmi), during a 45-day period. We measured the amount of straw N absorbed by lettuce, lost as N₂O or in leachates, and remaining in bulk soil and aggregate fractions. Lettuce biomass increased significantly (P < 0.05) by 37% with earthworms, and a greater proportion of the N uptake by lettuce was from the soil native N pool rather than from straw N (soil-derived N in lettuce increased from 101 to 170 mg pot⁻¹ with earthworms). Earthworms did not change N losses by leaching. Total cumulative N₂O emissions were 29% greater with earthworms than without earthworms (P < 0.05), but the straw-derived cumulative N₂O emission was three times lower with earthworms than without earthworms. Straw N was recovered in large macroaggregates (> 2 mm) and earthworm tissues in the microcosms with earthworms. There was 4.5% more straw N remaining in soil with earthworms, suggesting that earthworms temporarily increased the residence time of straw N. We propose that M. guillelmi stimulates short-term mineralization of soil native N, which is available for uptake by lettuce and increases the risk of N loss as N₂O, while temporarily stabilizing straw N in the soil.

蚯蚓刺激有机氮 (N) 矿化，这与植物对氮的吸收和土壤中的氮流失有关。蚯蚓还可以同时将富含氮的残留物转移到受物理保护的土壤部分并暂时增加氮的稳定性。本研究在 45 天期间评估了土壤微观世界中土壤 N 转化和生菜 N 吸收，该土壤微观世界使用¹⁵ N 标记的稻草，有和没有蚯蚓 ( Metaphire guillelmi ) 修正。我们测量了生菜吸收的稻草 N 量，损失为 N ₂O 或在渗滤液中，并保留在散装土壤和聚集体部分中。莴苣生物量显着增加（P < 0.05）37%，莴苣吸收的 N 更多来自土壤天然 N 库，而不是来自秸秆 N（生菜中的土壤衍生 N 从 101 增加到 170 mg带蚯蚓的锅^{-1 ）。}蚯蚓没有通过浸出改变氮损失。有蚯蚓的总累积 N ₂ O 排放量比没有蚯蚓的高 29%（P < 0.05），但秸秆衍生的累积 N ₂有蚯蚓的 O 排放量比没有蚯蚓的低三倍。秸秆 N 在具有蚯蚓的微观世界中的大型宏观聚集体（> 2 毫米）和蚯蚓组织中回收。有蚯蚓的土壤中残留的秸秆 N 增加了 4.5%，这表明蚯蚓暂时增加了秸秆 N 的停留时间。我们建议M. guillelmi刺激土壤原生 N 的短期矿化，这可被莴苣吸收并增加N 损失为 N ₂ O 的风险，同时暂时稳定土壤中的秸秆 N。