Fluxes of N2 and N2O and contributing processes in summer after grassland renewal and grassland conversion to maize cropping on a Plaggic Anthrosol and a Histic Gleysol
Fluxes of N2 and N2O and contributing processes in summer after grassland renewal and grassland conversion to maize cropping on a Plaggic Anthrosol and a Histic Gleysol
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DOI：
10.1016/j.soilbio.2016.06.028
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发表时间：
2016-10-01
影响因子：
9.7
通讯作者：
Well, Reinhard
中科院分区：
文献类型：
--
作者：
Buchen, Caroline;Lewicka-Szczebak, Dominika;Well, Reinhard
草地更新和将草地转为耕地是密集使用草地的常见农业做法，特别是在西北欧。然而，草地翻耕可导致土壤有机氮（N）矿化的冲击，由于土壤扰动，在耕作和分解残茬和根从旧的草地草地。这是已知的，导致增加一氧化二氮（N2 O）的排放量，但有关的基本微生物过程，特别是N2 O还原为N-2通过反硝化作用的作用，是稀缺的信息。因此，我们应用N-15气体通量法原位草地最近下耕玉米种植，更新的草地和永久性草地上的Histic潜育土和一个Plaggic人为土，不同的有机质含量和排水。我们使用针头注射N-15-标记的硝酸钾-在三个不同的深度在土壤中，以实现均匀的标签分布。标记添加后44天，测量N2 O和N-2的通量，矿物N浓度和N-15富集。总体而言，没有发现草地转换/更新和永久性草地之间的N2 O和N-2排放量的差异。当N2 O/（N2 O + N-2）比值较低时，反硝化作用的贡献很大。然而，N-15标记分布的异质性被证明是一个主要的困难，在水饱和的组织潜育土，并造成潜在的不确定性，在确定各种生产途径。较低的气体损失和较高的硝化潜力被检测到在阴坡人为土，表明草地转换/更新后可能浸出过量的矿物N的更高的威胁。(C)2016爱思唯尔有限公司版权所有
Grassland renewal and grassland conversion to arable land are common agricultural practices on intensively used grassland sites, especially in north-western Europe. However, grassland ploughing can cause a flush of soil organic nitrogen (N) mineralisation due to soil disturbance during tillage and decomposition of stubble and roots from the old grass sward. This is known to result in enhanced nitrous oxide (N2O) emissions, but information about the underlying microbial processes, especially the role of N2O reduction to N-2 via denitrification, is scarce. Therefore we applied the N-15 gas flux method in situ to grassland recently ploughed under for maize cropping, renewed grassland and permanent grassland on a Histic Gleysol and a Plaggic Anthrosol which differed in organic matter content and drainage. We used needle injection of N-15-labelled KNO3- at three different depths in the soil to achieve homogeneous label distribution. Fluxes of N2O and N-2, mineral N concentration and N-15 enrichment of these were measured for 44 days after label addition. Overall, no differences in N2O and N-2 emissions were found between grassland conversion/renewal and permanent grassland. N-2 emissions increased up to 9115 g N ha(-1) day(-1) on a single sampling day following grassland conversion to maize cropping on the Histic Gleysol, leading to a great contribution of denitrification when N2O/(N2O + N-2) ratio was low. However, heterogeneity of N-15 label distribution proved to be a major difficulty in the water-saturated Histic Gleysol and caused potential uncertainty in identification of various production pathways. Lower gaseous losses and higher nitrification potential were detected in the Plaggic Anthrosol, indicating a higher threat of possible leaching of excess mineral N following grassland conversion/renewal. (C) 2016 Elsevier Ltd. All rights reserved.