The transition year from tillage to no tillage in semiarid areas and its effects on nitrous oxide (N₂O) emissions and related microbial communities, as well as the potential interaction with N management, including enhanced-efficiency fertilisers, are not well studied despite their economic and environmental implications. In tilled and nontilled plots, the effectiveness of the double DMPSA + NBPT inhibitor (applied with urea at basal fertilisation) and that of DMPSA (applied with calcium ammonium nitrate at top-dressing) in the mitigation of N₂O emissions were evaluated in a rainfed barley (Hordeum vulgare L.) crop in central Spain. Crop yield, nitrogen (N) uptake, the abundances of key genes involved in nitrification and denitrification processes and meteorological conditions and soil ancillary properties were monitored. In addition, the composition of bacterial communities was determined by sequencing the 16S rRNA gene. Fertilisers with inhibitors decreased cumulative N₂O emissions and yield-scaled N₂O emissions by 53% and 56%, respectively, with respect to those without inhibitors, which coincided with a trend of increasing grain and biomass yield and aboveground N uptake (by 11.3%, 9.2% and 7.2%, respectively). The highest N₂O emissions were measured 49 days after harvest (immediately after a rainfall event that like reactivated soil microorganisms), reaching 15 mg N m⁻² d⁻¹ for the treatment with fertiliser without inhibitor combined with tillage. This peak was linked to a remarkable increase in the abundance of denitrifiers. The abundance of nitrifiers and denitrifiers successfully explained the N₂O dynamics observed after basal fertilisation (i.e. an increase in the amoA/nosZ ratio in fertilised plots with inhibitors, where the highest emissions were observed). Our results also showed a reduction in the abundance of the phylum Nitrospirae throughout the cropping period in the plots that received inhibitors. No tillage led to a higher abundance of Cyanobacteria, Verrucomicrobia and Bacteroidetes and resulted in better implantation of the crop and higher plant density compared with tillage, thus increasing yields and N use efficiency and decreasing N₂O emissions. Under the conditions of our study, shifting from conventional tillage to no tillage enhanced the balance between N use efficiency and yield-scaled N₂O emissions in the first year of conversion, particularity with the use of the double inhibitor with urea at basal fertilisation and DMPSA with CAN at dressing.

半干旱地区从耕作到免耕的过渡年及其对一氧化二氮 (N ₂ O) 排放和相关微生物群落的影响，以及与氮管理的潜在相互作用，包括增效肥料，尽管它们的研究尚未得到很好的研究。经济和环境影响。在耕地和非耕地中，双重 DMPSA + NBPT 抑制剂（在基础施肥时与尿素一起施用）和 DMPSA（在追肥时与硝酸铵钙一起施用）在减缓 N ₂ O 排放方面的有效性在雨养大麦（Hordeum vulgareL.) 西班牙中部的作物。监测作物产量、氮 (N) 吸收、参与硝化和反硝化过程的关键基因的丰度以及气象条件和土壤辅助特性。此外，通过对 16S rRNA 基因进行测序，确定了细菌群落的组成。与没有抑制剂的肥料相比，使用抑制剂的肥料使累积 N ₂ O 排放量和按产量规模的 N ₂ O 排放量分别减少了 53% 和 56%，这与谷物和生物量产量以及地上 N 吸收增加的趋势相吻合（通过分别为 11.3%、9.2% 和 7.2%）。最高 N ₂收获后 49 天测量 O 排放（在降雨事件后立即重新激活土壤微生物），在没有抑制剂的肥料与耕作相结合的处理中达到 15 mg N m ^-2 d ^{-1 。}这个峰值与反硝化菌丰度的显着增加有关。硝化菌和反硝化菌的丰度成功地解释了在基础施肥后观察到的 N ₂ O 动态（即，在使用抑制剂的施肥地块中，amoA / nosZ比率增加，其中观察到最高排放）。我们的结果还显示硝化螺菌门的丰度减少在接受抑制剂的地块的整个种植期间。与耕作相比，免耕导致蓝细菌、疣微菌和拟杆菌的丰度更高，并导致作物更好的植入和更高的植物密度，从而提高产量和氮利用效率并减少 N ₂ O 排放。在我们的研究条件下，从常规耕作转向免耕提高了转换第一年氮利用效率和产量规模的 N ₂ O 排放之间的平衡，特别是在基础施肥时使用尿素双重抑制剂和DMPSA 与 CAN 在敷料。