Straw return affects the soil N supply; however, the mechanisms underlying the effects of different straw types and substance additions on soil N availability remain elusive. This study compared net N mineralization (NNM) in soils with various straw management histories under rotations rice-fallow (RF), rice-wheat (RW) and rice-potato with straw mulch (RP) during 2003–2017. The soils were then subjected to four substrate additions, including the no-substrate control, +N [(NH₄)₂SO_4, 0.2 mg N kg⁻¹ dry soil], +G (glucose, 0.6 mg C kg⁻¹ dry soil) and +G+N (both). The responses of the soil NNM to substrate additions varied depending on the soils’ different straw histories. The direction of NNM was affected by substrate addition, but the magnitude depended on crop rotation and straw management. The NNM in the +G treatment ranged from 15.5 to 71.5 mg kg⁻¹ in the soils with various straw histories, with RW and RP having 299% and 366% greater NNM than RF, respectively. Conversely, the addition of +N and +G+N decreased the soil NNM significantly in the soil with RW and RP straw histories, being 70~75% and 28~39% lower in the +N and +G+N treatments, respectively, than in the soil without straw history (RF). In addition, long-term straw return (RP and RW) significantly increased the soil ammonium N, amino acid N, and microbial biomass C and extracellular enzyme activity, while the addition of N and C substrates altered the decomposition of soil organic N. The long-term straw history also affected the soil bacterial community and formed a significant grouping compared to RF. In general, the soil from RF was dominated by heterotrophic bacteria such as Actinobacteria, Bacteroidetes and Proteobacteria, while the soils of RP and RW were mainly Firmicutes involved in straw glycolysis and part of Proteobacteria involved in N metabolism. Adding inorganic N altered bacteria in Proteobacteria, and the relative abundance of Proteobacteria had a negative relationship with the concentration of available N, indicating that bacteria induced by exogenous N were not involved in inherent N mineralization in soil. The addition of glucose enhanced the bacterial communities involved in N mineralization. The results imply that the soil N supply capability was enhanced with straw history under N deficiency and that an excess supply of N fertilizers was immobilized to minimize leaching losses.

秸秆还田影响土壤氮供应；然而，不同秸秆类型和物质添加对土壤氮可用性影响的潜在机制仍然难以捉摸。本研究比较了 2003 年至 2017 年在稻谷-休耕（RF）、稻-小麦（RW）和稻-马铃薯（RP）轮作下，具有不同秸秆管理历史的土壤中的净氮矿化（NNM）。然后对土壤添加四种底物，包括无底物对照、+N [(NH ₄ ) ₂ SO _4, 0.2 mg N kg ^-1干燥土壤]、+G（葡萄糖，0.6 mg C kg ^-1干土）和+G+N（两者）。土壤 NNM 对底物添加的反应因土壤不同的秸秆历史而异。NNM的方向受基质添加的影响，但大小取决于轮作和秸秆管理。+G 处理中的 NNM 范围为 15.5 至 71.5 mg kg ^-1在具有不同秸秆历史的土壤中，RW 和 RP 的 NNM 分别比 RF 高 299% 和 366%。相反，添加 +N 和 +G+N 显着降低了具有 RW 和 RP 秸秆历史的土壤中的 NNM，在 +N 和 +G+N 处理中分别降低了 70~75% 和 28~39% , 而不是在没有秸秆历史 (RF) 的土壤中。此外，长期秸秆还田（RP 和 RW）显着增加了土壤铵态氮、氨基酸 N 和微生物生物量 C 和胞外酶活性，而 N 和 C 底物的添加改变了土壤有机 N 的分解。长期的秸秆历史也影响了土壤细菌群落，并与 RF 相比形成了一个显着的群体。总的来说，RF 的土壤以异养细菌为主，如放线菌、拟杆菌和变形菌，而RP和RW的土壤主要是参与秸秆糖酵解的厚壁菌和参与氮代谢的部分变形菌。在变形菌中添加无机氮改变细菌，变形菌的相对丰度与有效氮浓度呈负相关，表明外源氮诱导的细菌不参与土壤中固有的氮矿化。添加葡萄糖增强了参与 N 矿化的细菌群落。结果表明，在 N 缺乏的情况下，随着秸秆历史的发展，土壤 N 供应能力得到增强，并且固定了过量的 N 肥料供应，以最大限度地减少浸出损失。在变形菌中添加无机氮改变细菌，变形菌的相对丰度与有效氮浓度呈负相关，表明外源氮诱导的细菌不参与土壤中固有的氮矿化。添加葡萄糖增强了参与 N 矿化的细菌群落。结果表明，在 N 缺乏的情况下，随着秸秆历史的发展，土壤 N 供应能力得到增强，并且固定了过量的 N 肥料供应，以最大限度地减少浸出损失。在变形菌中添加无机氮改变细菌，变形菌的相对丰度与有效氮浓度呈负相关，表明外源氮诱导的细菌不参与土壤中固有的氮矿化。添加葡萄糖增强了参与 N 矿化的细菌群落。结果表明，在 N 缺乏的情况下，随着秸秆历史的发展，土壤 N 供应能力得到增强，并且固定了过量的 N 肥料供应，以最大限度地减少浸出损失。添加葡萄糖增强了参与 N 矿化的细菌群落。结果表明，在 N 缺乏的情况下，随着秸秆历史的发展，土壤 N 供应能力得到增强，并且固定了过量的 N 肥料供应，以最大限度地减少浸出损失。添加葡萄糖增强了参与 N 矿化的细菌群落。结果表明，在 N 缺乏的情况下，随着秸秆历史的发展，土壤 N 供应能力得到增强，并且固定了过量的 N 肥料供应，以最大限度地减少浸出损失。