Microbial activity differentially regulates the vertical mobility of nitrogen compounds in soil
Microbial activity differentially regulates the vertical mobility of nitrogen compounds in soil
复制标题
DOI：
10.1016/j.soilbio.2012.05.003
复制
发表时间：
2012-10-01
影响因子：
9.7
通讯作者：
Jones, D. L.
中科院分区：
文献类型：
--
作者：
Abaas, E.;Hill, P. W.;Jones, D. L.
在许多农业生态系统中，溶解有机氮（DON）与硝酸盐一起是一个重要的氮素损失途径。为了更好地了解控制土壤中DON淋溶的因素，我们跟踪了N-15标记的NO3-，NH 4+，丙氨酸和三丙氨酸在填充土柱中的垂直运动，以响应模拟降雨事件。我们发现，在高压灭菌（无菌）土壤中，吸附被认为是占主导地位的调节因素，淋溶遵循系列NO3- >三丙氨酸>丙氨酸> NH 4+。在非无菌填充土柱中，NO3-浸出的快速速率不受影响，而氨基酸，肽和NH 4+的运动几乎完全阻止由于微生物固定化。我们的研究结果支持了以下观点：（1）农业土壤中DON的损失主要以柠檬酸盐化合物（如腐殖酸DON）的形式发生，而不是以不稳定的低分子量DON（如寡肽和氨基酸）的形式发生;（2）尽管硝酸盐是生物可利用的，但它不是C限制的微生物生物量的优选N形式。(C)2012爱思唯尔有限公司保留所有权利。
Alongside nitrate, dissolved organic nitrogen (DON) represents a significant N loss pathway in many agroecosystems. To better understand the factors controlling DON leaching in soil we followed the vertical movement of N-15-labeled NO3-, NH4+, alanine and trialanine in packed soil columns in response to a simulated rainfall event. We show that in autoclaved (sterile) soil where sorption is assumed to be the dominant regulating factor, leaching followed the series NO3- > trialanine > alanine > NH4+. In the non-sterile packed soil columns, the rapid rate of NO3- leaching was unaffected whilst the movement of the amino acid, peptide and NH4+ was almost completely prevented due to microbial immobilization. Our results support the view that (1) DON loss from agricultural soils occurs mainly in the form of recalcitrant compounds (e.g. humic DON) rather than in the form of labile low MW DON (e.g. oligopeptides and amino acids), and (2) that although nitrate was bioavailable, it was not a preferred N form for the C-limited microbial biomass. (C) 2012 Elsevier Ltd. All rights reserved.