Soil organic nitrogen (N) mineralization not only supports ecosystem productivity but also weakens carbon and N accumulation in soils. Recalcitrant (mainly mineral‐associated organic matter) and labile (mainly particulate organic matter) organic materials differ dramatically in nature. Yet, the patterns and drivers of recalcitrant (MNrec) and labile (MNlab) organic N mineralization rates and their consequences on ecosystem N retention are still unclear. By collecting MNrec (299 observations) and MNlab (299 observations) from 57 15N tracing studies, we found that soil pH and total N were the master factors controlling MNrec and MNlab, respectively. This was consistent with the significantly higher rates of MNrec in alkaline soils and of MNlab in natural ecosystems. Interestingly, our analysis revealed that MNrec directly stimulated microbial N immobilization and plant N uptake, while MNlab stimulated the soil gross autotrophic nitrification which discouraged ammonium immobilization and accelerated nitrate production. We also noted that MNrec was more efficient at lower precipitation and higher temperatures due to increased soil pH. In contrast, MNlab was more efficient at higher precipitation and lower temperatures due to increased soil total N. Overall, we suggest that increasing MNrec may lead to a conservative N cycle, improving the ecosystem services and functions, while increasing MNlab may stimulate the potential risk of soil N loss.

中文翻译：

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土壤顽固但不稳定的有机氮矿化有助于微生物氮固定和植物氮吸收

土壤有机氮（N）矿化不仅支持生态系统生产力，而且削弱土壤中碳和氮的积累。顽固性（主要是矿物相关有机物）和不稳定（主要是颗粒有机物）有机材料在性质上存在显着差异。然而，顽抗的模式和驱动因素（中号内雷克) 和不稳定 (中号国家实验室）有机氮矿化率及其对生态系统氮保留的影响仍不清楚。通过收集中号内雷克（299 个观察结果）和中号国家实验室（299 条观察结果）来自 5715氮追踪研究发现，土壤pH值和全氮是控制氮的主要因素。中号内雷克和中号国家实验室， 分别。这与显着较高的比率一致中号内雷克在碱性土壤和中号国家实验室在自然生态系统中。有趣的是，我们的分析表明中号内雷克直接刺激微生物氮固定和植物氮吸收，同时中号国家实验室刺激土壤总自养硝化作用，阻碍铵的固定并加速硝酸盐的产生。我们还注意到中号内雷克由于土壤 pH 值增加，在降水量较低和温度较高时效率更高。相比之下，中号国家实验室由于土壤总氮的增加，在较高降水量和较低温度下效率更高。总体而言，我们建议增加中号内雷克可能会导致保守的氮循环，改善生态系统服务和功能，同时增加中号国家实验室可能会激发土壤氮流失的潜在风险。