The abundance of nitrogen cycle genes and potential greenhouse gas fluxes depends on land use type and little on soil aggregate size
The abundance of nitrogen cycle genes and potential greenhouse gas fluxes depends on land use type and little on soil aggregate size
复制标题
DOI：
10.1016/j.apsoil.2017.11.026
复制
发表时间：
2018-04-01
影响因子：
4.8
通讯作者：
Banwart, Steve
中科院分区：
文献类型：
--
作者：
Blaud, Aimeric;van der Zaan, Bas;Banwart, Steve
已知土壤结构影响土壤中的微生物群落，而土壤团聚体是支持土壤功能的基本生态组织单元。然而，仍然知之甚少的微生物群落的分布和功能之间的土壤团聚体粒径与土地利用。因此，本研究的目的是确定与氮循环和潜在温室气体（GHG）通量相关的微生物群落的基因丰度在6种土壤团聚体大小（0-0.25，0.25-0.5，0.5-1.0，1-2，2-5，5-10 mm）的4种土地利用（即草地，农田，森林，幼林）。采用定量PCR（Q-PCR）研究细菌、古细菌和真菌的丰度，以及参与固氮（nifH基因）、硝化（细菌和古细菌amoA基因）和反硝化（narG、nirS和nosZ基因）的功能性行会。土地利用导致所分析的所有基因的丰度显着不同，其中农田地点除amoA细菌和古细菌外，所有基因的丰度最低。相比之下，没有一个单一的土地利用一贯表现出最高的基因丰度的所有基因的调查。聚集大小类之间的基因丰度的变化也被发现，但模式是基因特异性的，没有共同的趋势，在土地利用。然而，在0.5-1.0 mm的大小级别的聚集体显示出高的细菌16 S，nifH，amoA细菌，narG，nirS和nosZ基因丰度的两个森林网站，但不是真菌ITS和古菌16 S。潜在的温室气体通量的影响，土地利用，但影响远不如微生物基因丰度，土地利用和土壤团聚体不一致。然而，土壤团聚体大小之间的温室气体通量的差异不大。从这项研究中，土地利用出现的占主导地位的因素，解释了N功能社区和潜在的温室气体通量在土壤中的分布，不太明显，不太普遍的影响，总规模。
Soil structure is known to influence microbial communities in soil and soil aggregates are the fundamental ecological unit of organisation that support soil functions. However, still little is known about the distribution of microbial communities and functions between soil aggregate size fractions in relation to land use. Thus, the objective of this study was to determine the gene abundance of microbial communities related to the nitrogen cycle and potential greenhouse gas (GHG) fluxes in six soil aggregate sizes (0-0.25, 0.25-0.5, 0.5-1.0, 1-2, 2-5, 5-10 mm) in four land uses (i.e. grassland, cropland, forest, young forest). Quantitative-PCR (Q-PCR) was used to investigate the abundance of bacteria, archaea and fungi, and functional guilds involved in N-fixation (nifH gene), nitrification (bacterial and archaeal amoA genes) and denitrification (narG, nirS, and nosZ genes). Land use leads to significantly different abundances for all genes analysed, with the cropland site showing the lowest abundance for all genes except amoA bacteria and archaea. In contrast, not a single land use consistently showed the highest gene abundance for all the genes investigated. Variation in gene abundance between aggregate size classes was also found, but the patterns were gene specific and without common trends across land uses. However, aggregates within the size class of 0.5-1.0 mm showed high bacterial 16S, nifH, amoA bacteria, narG, nirS and nosZ gene abundance for the two forest sites but not for fungal ITS and archaeal 16S. The potential GHG fluxes were affected by land use but the effects were far less pronounced than for microbial gene abundance, inconsistent across land use and soil aggregates. However, few differences in GHG fluxes were found between soil aggregate sizes. From this study, land use emerges as the dominant factor that explains the distribution of N functional communities and potential GHG fluxes in soils, with less pronounced and less generalized effects of aggregate size.