When applied to soils, ‘biodiesel co-product’ (BCP) functions as a labile source of organic C for microorganisms and promotes immobilisation of inorganic N (otherwise susceptible to leaching). However, the effects on biological N transformations and greenhouse gas (GHG) emissions, have not yet been investigated. Therefore, we investigated these effects with BCP amendment of soils at water contents ranging from 40 to 100% water holding capacity (WHC). The BCP applications significantly increased soil microbial biomass C, N, and ATP contents at all soil moistures, but maximally at 60% WHC. Amendment with BCP increased the abundance of nosZ genes coding for N₂O reductase, and temporarily increased emissions of N₂O up to day 3, but from day 7 onwards, emissions of N₂O at all water contents almost stopped. Consequently, BCP suppressed total N₂O emissions from waterlogged soil (100% WHC) by about 40% at 56 days, while the greatest emissions of N₂O were still observed at 80% WHC. BCP significantly increased the abundance of ammonia oxidising archaea (AOA) and ammonia oxidising bacteria (AOB) at lower moisture contents (40% and 60% WHC) at day 7. In summary, our results suggest that BCP disproportionately increased the genetic capacity for the final reactions of denitrification by nosZ compared with those genes more implicated in early reactions of denitrification (nirS and nirK).

当应用于土壤时，“生物柴油副产品”（BCP）可作为微生物有机C的不稳定来源，并促进无机N的固定化（否则易于浸出）。但是，尚未研究对生物氮转化和温室气体（GHG）排放的影响。因此，我们研究了在含水量为40％至100％持水量（WHC）的土壤中BCP改良剂对土壤的这些影响。BCP施用显着增加了所有土壤湿度下土壤微生物生物量的C，N和ATP含量，但最高达到60％WHC。BCP修正案增加了编码N ₂ O还原酶的nosZ基因的丰度，并暂时增加了N _2的排放O直到第3天，但从第7天开始，所有含水量的N ₂ O排放都几乎停止了。因此，BCP在56天时抑制了淹水土壤（100％WHC）中的N ₂ O排放总量约40％，而在WHC 80％时仍观察到最大的N ₂ O排放量。在较低的水分含量（40％和60％WHC）下，BCP在第7天显着增加了氨氧化古细菌（AOA）和氨氧化细菌（AOB）的丰度。总而言之，我们的结果表明，BCP不成比例地增加了BCP的遗传能力。与nosZ反硝化作用的最终反应相比，nosZ的最终反应与反硝化作用的早期反应（nirS和nirK）牵涉更多的那些基因相比。