Most soil N transformations studies are carried out using soil incubations without plants, despite the fact that plant-soil interactions potentially influence soil N dynamics. In this study, gross N transformation rates were quantified using a subtropical acidic forest with and without plants (and under different soil storage conditions). The results showed that the gross rates of N mineralization in air-dried and rewetted soil significantly increased, while the gross rates of nitrification and immobilization decreased, compared with fresh soil. Soil storage for more than one month at 4 °C (typical refrigerated conditions) and room temperature (25 °C) did not affect the gross rates of soil N mineralization and immobilization but significantly inhibited heterotrophic nitrification rates. Moreover, plants grown in the soil significantly stimulated gross rates of N mineralization, autotrophic and heterotrophic nitrification, and NO₃⁻ immobilization. Plant NH₄⁺ uptake rates (3.74 mg N kg⁻¹ d⁻¹) were 374 times greater than the NH₄⁺ immobilization rate (0.01 mg N kg⁻¹ d⁻¹). The competition for NH₄⁺ between plants and soil microorganisms led to strong feedback effects on soil N transformations. Based on our results we recommend to carry out ¹⁵N tracing studies with plants to more realistically mimic field conditions. ¹⁵N tracing techniques in combination with ¹⁵N-tracing models, such as Ntrace_Plant, provide a robust method to quantify soil N transformations and plant N uptake rates in plant-soil systems.

尽管植物与土壤之间的相互作用可能会影响土壤氮素的动态，但大多数土壤氮素转化的研究都是在没有植物的条件下进行的。在这项研究中，总氮转化率通过使用带和不带植物的亚热带酸性森林（以及在不同的土壤储存条件下）进行定量。结果表明，与新鲜土壤相比，风干和再湿润的土壤中N矿化的总速率显着提高，而硝化和固定化的总速率却降低。土壤在4°C（典型的冷藏条件）和室温（25°C）下储存一个月以上不会影响土壤氮矿化和固定化的总速率，但会显着抑制异养硝化率。而且，₃ ^-固定。植物的NH ₄ ⁺吸收率（3.74 mg N kg ^-1 d ^-1）是NH ₄ ⁺固定率（0.01 mg N kg ^-1 d ^-1）的374倍。植物与土壤微生物之间的NH ₄ ⁺竞争导致对土壤氮转化的强烈反馈作用。根据我们的结果，我们建议对植物进行¹⁵ N示踪研究，以更实际地模拟田间条件。^15种N跟踪技术与^15种N跟踪模型结合使用，例如Ntrace _Plant，提供了一种可靠的方法来量化植物-土壤系统中土壤氮的转化和植物对氮的吸收率。