通过硝化抑制剂（NI）与肥料的混合施用来抑制硝化作用，是一种降低肥料导致氧化亚氮（N₂O）排放的有效方法。3,4-二甲基吡唑磷酸盐（DMPP）对氨氧化细菌（AOB）的抑制效果明显大于氨氧化古菌（AOA），AOB和AOA分别在碱性和酸性土壤中主导硝化作用。然而，氮源与土壤性质的相互作用对DMPP 功效的影响仍不清楚。因此，我们通过施加不同浓度的DMPP，选用digestate和尿素作为肥料，对三种pH不同的中国典型农田土壤（潮土、黑土和红土）进行了微宇宙试验。在碱性潮土中，施用尿素和digestate均引发N₂O排放高峰（60 ug N kg^-1 day^-1），这与施肥后3天内快速的硝化作用相一致。DMPP减少了约90% N₂O排放峰，尽管硝化速率仅降低50%。在酸性黑土中，只有digestate能促进N₂O排放，其排放量随时间逐渐增加，在5-7天后出现排放高峰（20 ug N kg^-1 day^-1）。在黑土中，DMPP对硝化速率和N₂O排放均有轻微的抑制，N₂O产率(N₂O-N/NO₂^-+NO₃^--N )高达3.5%，表明digestate诱导了异养反硝化作用。在酸性红壤中，digestate和尿素处理的N₂O排放峰值分别为50和10 ug N kg^-1 day^-1，DMPP使该速率大幅下降近70%。与0.5% DMPP处理相比，更高浓度的DMPP（1.0-1.5%）在这些土壤中（包括digestate和尿素）对N₂O排放的抑制作用均不显著（P<0.05）。我们的研究强调了氮源、土壤性质和NI的匹配对高效减少N₂O排放的重要性。

The inhibition of nitrification by mixing nitrification inhibitors (NI) with fertilizers is emerging as an effective method to reduce fertilizer-induced nitrous oxide (N₂O) emissions.  The additive 3,4-dimethylpyrazole phosphate (DMPP) apparently inhibits ammonia oxidizing bacteria (AOB) more than ammonia oxidizing archaea (AOA), which dominate the nitrification in alkaline and acid soil, respectively.  However, the efficacy of DMPP in terms of nitrogen sources interacting with soil properties remains unclear.  We therefore conducted a microcosm experiment using three typical Chinese agricultural soils with contrasting pH values (fluvo-aquic soil, black soil and red soil), which were fertilized with either digestate or urea in conjunction with a range of DMPP concentrations.  In the alkaline fluvo-aquic soil, fertilization with either urea or digestate induced a peak in N₂O emission (60 μg N kg^–1 d^–1) coinciding with the rapid nitrification within 3 d following fertilization.  DMPP almost eliminated this peak in N₂O emission, reducing it by nearly 90%, despite the fact that the nitrification rate was only reduced by 50%.  In the acid black soil, only the digestate induced an N₂O emission that increased gradually, reaching its maximum (20 μg N kg^–1 d^–1) after 5–7 d.  The nitrification rate and N₂O emission were both marginally reduced by DMPP in the black soil, and the N₂O yield (N₂O-N per NO₂^–+NO₃^–-N produced) was exceptionally high at 3.5%, suggesting that the digestate induced heterotrophic denitrification.  In the acid red soil, the N₂O emission spiked in the digestate and urea treatments at 50 and 10 μg N kg^–1 d^–1, respectively, and DMPP reduced the rates substantially by nearly 70%.  Compared with 0.5% DMPP, the higher concentrations of DMPP (1.0 to 1.5%) did not exert a significantly (P<0.05) better inhibition effect on the N₂O emissions in these soils (either with digestate or urea).  This study highlights the importance of matching the nitrogen sources, soil properties and NIs to achieve a high efficiency of N₂O emission reduction.