Lifei Sun, Yanci Qiao, Wolfgang Wanek, Daryl L. Moorhead, Yongxing Cui, Yujiao Peng, Liquan Song, Baoqing Hu, Tuo Zhang, Shuailin Li
{"title":"Nitrogen input decreases microbial nitrogen use efficiency in surface soils of a temperate forest in northeast China","authors":"Lifei Sun, Yanci Qiao, Wolfgang Wanek, Daryl L. Moorhead, Yongxing Cui, Yujiao Peng, Liquan Song, Baoqing Hu, Tuo Zhang, Shuailin Li","doi":"10.1016/j.geoderma.2024.117159","DOIUrl":null,"url":null,"abstract":"Microbial nitrogen use efficiency (NUE) reflects the allocation of microbially-acquired N between growth (anabolism) and the release of inorganic N to the environment (catabolism), and is central to understanding soil N cycling. However, the effects of N addition on microbial NUE are unclear. We determined microbial NUE in surface (0–10 cm) and subsurface (10–20 cm) soils in a temperate forest by the combined substrate-independent <ce:sup loc=\"post\">18</ce:sup>O-H<ce:inf loc=\"post\">2</ce:inf>O tracer technique and <ce:sup loc=\"post\">15</ce:sup>N isotope pool dilution in a multi-level N addition experiment. We found that high N treatment (75 kg N ha<ce:sup loc=\"post\">−1</ce:sup> yr<ce:sup loc=\"post\">−1</ce:sup> as urea fertilizer) significantly decreased NUE in surface soil, but not in the subsurface soil. The decrease in NUE in surface soil was related to soil acidification, likely induced by N addition, and to reduced phosphorus availability, suggesting increased phosphorus limitation to microbial metabolism with N addition. Microbial NUE was inversely related to inorganic N flux (as NH<ce:inf loc=\"post\">4</ce:inf><ce:sup loc=\"post\">+</ce:sup>) in both surface and subsurface soils and positively related to microbial biomass in surface soil. Our empirical evidence confirms that microbial NUE is a sensitive proxy and controlling branchpoint between soil microbial N immobilization and inorganic N cycling, which should be explicitly included in biogeochemical models to better predict soil N dynamics.","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"87 1","pages":""},"PeriodicalIF":5.6000,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geoderma","FirstCategoryId":"97","ListUrlMain":"https://doi.org/10.1016/j.geoderma.2024.117159","RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"SOIL SCIENCE","Score":null,"Total":0}
引用次数: 0
Abstract
Microbial nitrogen use efficiency (NUE) reflects the allocation of microbially-acquired N between growth (anabolism) and the release of inorganic N to the environment (catabolism), and is central to understanding soil N cycling. However, the effects of N addition on microbial NUE are unclear. We determined microbial NUE in surface (0–10 cm) and subsurface (10–20 cm) soils in a temperate forest by the combined substrate-independent 18O-H2O tracer technique and 15N isotope pool dilution in a multi-level N addition experiment. We found that high N treatment (75 kg N ha−1 yr−1 as urea fertilizer) significantly decreased NUE in surface soil, but not in the subsurface soil. The decrease in NUE in surface soil was related to soil acidification, likely induced by N addition, and to reduced phosphorus availability, suggesting increased phosphorus limitation to microbial metabolism with N addition. Microbial NUE was inversely related to inorganic N flux (as NH4+) in both surface and subsurface soils and positively related to microbial biomass in surface soil. Our empirical evidence confirms that microbial NUE is a sensitive proxy and controlling branchpoint between soil microbial N immobilization and inorganic N cycling, which should be explicitly included in biogeochemical models to better predict soil N dynamics.
微生物氮利用效率(NUE)反映了微生物获得的氮在生长(合成代谢)和向环境释放无机氮(分解代谢)之间的分配,是理解土壤氮循环的核心。然而,氮添加对微生物氮肥利用效率的影响尚不清楚。采用与底物无关的18O-H2O示踪技术和15N同位素池稀释相结合的多层次加氮实验,测定了温带森林表层(0-10 cm)和地下(10-20 cm)土壤的微生物氮肥利用效率。我们发现,高氮处理(75 kg N ha - 1 yr - 1作为尿素肥)显著降低了表层土壤的氮素利用效率,但对地下土壤没有影响。表层土壤氮素利用效率的下降与土壤酸化(可能是由N添加引起的)和磷有效性的降低有关,表明添加N增加了磷对微生物代谢的限制。微生物氮素利用效率与表层和地下土壤无机氮通量(如NH4+)呈负相关,与表层土壤微生物生物量呈正相关。我们的经验证据证实,微生物氮素利用效率是土壤微生物氮固定和无机氮循环之间的敏感代理和控制分支点,应明确将其纳入生物地球化学模型,以更好地预测土壤氮动态。
期刊介绍:
Geoderma - the global journal of soil science - welcomes authors, readers and soil research from all parts of the world, encourages worldwide soil studies, and embraces all aspects of soil science and its associated pedagogy. The journal particularly welcomes interdisciplinary work focusing on dynamic soil processes and functions across space and time.