Our understanding of how plants influence the gross rates of specific soil N transformations in plant-soil systems is still rudimentary, providing the incentive for our current study. A ¹⁵N tracing study was carried out with plants known for their NH₄⁺-preference to quantify the gross soil N transformation and gross plant N uptake rates. Significant interactions between plants and gross rates of soil N transformations were observed. The rates of NH₄⁺ uptake by sugarcane (3.74 mg N kg⁻¹ d⁻¹) and tea (3.34 mg N kg⁻¹ d⁻¹) were much higher than microbial NH₄⁺ immobilization rates (0.01, and 0.27 mg N kg⁻¹ d⁻¹, respectively), suggesting that NH₄⁺-preferring plants outcompeted microbial NH₄⁺ acquisition. The gross rates of NO₃⁻ immobilization increased with decreasing gross NH₄⁺ immobilization rates, indicating a switch towards microbial NO₃⁻ uptake under high plant NH₄⁺ demand. Moreover, the gross rates of autotrophic nitrification, the classical NO₃⁻ production pathway, was generally low in the studied acidic soil (average 0.40 mg N kg⁻¹ d⁻¹ in plant treatments), and was insufficient to meet the total NO₃⁻ demand (average 2.37 mg N kg⁻¹ d⁻¹). Gross rates of heterotrophic nitrification, ranging from 0.31 to 0.57 mg N kg⁻¹ d⁻¹, were stimulated by the presence of plants and were generally responsible for 49–69% of total NO₃⁻ production in the plant treatments, while this rate was negligible in the absence of plant. Heterotrophic nitrification might provide additional NO₃⁻ to meet N requirements of plants and microorganisms. This is supported by the positive correlation of gross heterotrophic nitrification coupled with gross NO₃⁻ immobilization and plant N uptake rates. Interactions between plant N acquisition and soil N transformations exist and plant-soil studies are key to identify feedbacks between plants and soil microbes.

我们对植物如何影响植物-土壤系统中特定土壤氮转化的总速率的理解仍然是基本的，为我们当前的研究提供了动力。一个¹⁵ N种描绘研究，为他们的NH称为植物进行了₄ ⁺ -preference量化总土壤氮转化和总植株氮的吸收率。观察到植物与土壤氮转化的总速率之间存在显着的相互作用。甘蔗（3.74 mg N kg ^-1 d ^-1）和茶（3.34 mg N kg ^-1 d ^-1）对NH ₄ ^+的吸收速率远高于微生物NH ₄ ⁺固定化率（分别为0.01和0.27 mg N kg ^-1 d ^-1），这表明优选NH ₄ ^+的植物胜过微生物NH ₄ ^+的吸收。NO的总速率₃ ^-固定化随毛NH增加_4分⁺固定化率，这表明朝向微生物NO开关₃ ^-摄取在高植物NH ₄ ⁺的需求。此外，自养硝化的总速率，古典NO ₃ ^-生产途径，是在所研究的酸性土通常较低（平均0.40毫克N-千克^-1 d^-1在植物处理），并不足以满足总NO ₃ ^-的需求（平均2.37毫克N-千克^-1 d ^-1）。异养硝化的总速率，范围从0.31至0.57毫克N-千克^-1 d ^-1，由植物的存在刺激和普遍负责总NO的49-69％₃ ^-生产在植物处理中，而此速率在没有植物的情况下微不足道。异养硝化作用可能会提供额外的NO _3- ^，以满足植物和微生物对氮的需求。总异养硝化与总NO ₃的正相关性支持了这一点。⁻固定化和植物氮吸收率。植物氮素吸收与土壤氮素转化之间存在相互作用，植物土壤研究是确定植物与土壤微生物之间反馈的关键。