Lashermes Gwenaëlle, Recous Sylvie, Alavoine Gonzague, Janz Baldur, Butterbach-Bahl Klaus, Ernfors Maria, Laville Patricia
Université de Reims Champagne Ardenne, INRAE, FARE, UMR A 614, 51097 Reims, France.
Université de Reims Champagne Ardenne, INRAE, FARE, UMR A 614, 51097 Reims, France.
Sci Total Environ. 2022 Feb 1;806(Pt 4):150883. doi: 10.1016/j.scitotenv.2021.150883. Epub 2021 Oct 12.
The emission of nitrous oxide (NO), a strong greenhouse gas, during crop residue decomposition in the soil can offset the benefits of residue recycling. The IPCC inventory considers agricultural NO emissions proportional to the amount of nitrogen (N) added by residues to soils. However, NO involves several emission pathways driven directly by the form of N returned and indirectly by changes in the soil induced by decomposition. We investigated the decomposition factors related to NO emissions under controlled conditions. Residues of sugar beet (SUB), wheat (WHT), rape seed (RAS), potato (POT), pea (PEA), mustard (MUS), red clover (RC), alfalfa (ALF), and miscanthus (MIS), varying by maturity at the time of collection, were incubated in two soils (GRI and SLU) at 15 °C with a water-filled pore space of 60%. The residues contained a wide proportion range of water-soluble components, components soluble in neutral detergent (SOL-NDS), hemicellulose, cellulose, and lignin. Their composition drastically influenced the dynamics of C mineralization and soil ammonium and nitrate and was correlated with NO flux dynamics. The net cumulative NO emitted after 60 days originated mostly from MUS (4828 ± 892 g N-NO ha), SUB (2818 ± 314 g N-NO ha) and RC (2567 ± 1245 g N-NO ha); the other residue treatments had much lower emissions (<200 g N-NO ha). For the first time NO emissions could be explained only by the residue content in the SOL-NDS, according to an exponential relationship. Residues with a high SOL-NDS (>25% DM) were also non-senescent and promoted high NO emissions (representing 1-5% of applied N), likely directly by nitrification and indirectly by denitrification in microbial hotspots. Crop residue quality appears to be valuable information for accurately predicting NO emissions and objectively weighing their other potential benefits to agriculture and the environment.
一氧化二氮（NO）是一种强效温室气体，在土壤中作物残茬分解过程中排放，这可能会抵消残茬循环利用的益处。政府间气候变化专门委员会（IPCC）清单认为农业NO排放与残茬添加到土壤中的氮（N）量成正比。然而，NO涉及多种排放途径，这些途径直接由归还的N形态驱动，间接由分解引起的土壤变化驱动。我们在受控条件下研究了与NO排放相关的分解因素。采集时成熟度不同的甜菜（SUB）、小麦（WHT）、油菜籽（RAS）、马铃薯（POT）、豌豆（PEA）、芥菜（MUS）、红三叶草（RC）、苜蓿（ALF）和芒草（MIS）残茬，在两种土壤（GRI和SLU）中于15℃下进行培养，土壤的水分填充孔隙度为60%。这些残茬含有比例范围广泛的水溶性成分、可溶于中性洗涤剂的成分（SOL-NDS）、半纤维素、纤维素和木质素。它们的组成极大地影响了碳矿化以及土壤铵和硝酸盐的动态变化，并与NO通量动态相关。60天后排放的净累积NO主要来自芥菜（4828±892 g N-NO/公顷）、甜菜（2818±314 g N-NO/公顷）和红三叶草（2567±1245 g N-NO/公顷）；其他残茬处理的排放量要低得多（<200 g N-NO/公顷）。根据指数关系，首次发现NO排放仅可由SOL-NDS中的残茬含量来解释。具有高SOL-NDS（>25%干物质）的残茬也是非衰老的，并且促进了高NO排放（占施用N的1-5%），可能直接通过硝化作用，间接通过微生物热点区域的反硝化作用。作物残茬质量似乎是准确预测NO排放以及客观权衡其对农业和环境的其他潜在益处的有价值信息。
