N2O emission from cropland field soil through fungal denitrification after surface applications of organic fertilizer
N2O emission from cropland field soil through fungal denitrification after surface applications of organic fertilizer
复制标题
DOI：
10.1016/j.soilbio.2013.10.044
复制
发表时间：
2014-02-01
影响因子：
9.7
通讯作者：
Senoo, Keishi
中科院分区：
文献类型：
--
作者：
Wei, Wei;Isobe, Kazuo;Senoo, Keishi
农田是大气中氧化亚氮（N2O）的最大人为来源之一。真菌被认为对陆地环境中的N2O排放有很大贡献；然而，真菌在农业领域的贡献程度以及相关真菌群落的系统发育和生理性质在很大程度上是未知的。本研究的重点是在地表施用颗粒有机肥后，农田土壤中大量的N2O排放。施用颗粒有机肥明显被真菌菌丝覆盖。建立了模拟田间观测的土壤微观环境试验。添加真菌抑制剂环己亚胺（cycloheximide）和细菌抑制剂链霉素（streptomycin）后，表面有机肥处理后N2O排放量分别减少了84%和20%，表明真菌是N2O排放的主要来源。采用菌落计数、变性梯度凝胶电泳及随后的系统发育分析等方法测定了田间表肥和非表肥土壤中真菌的种群密度和群落组成。从土壤中分离到34株真菌，并对其产N2O活性进行了分析。表层施肥土壤真菌种群密度（2.6 × 10(6) CFU/g）显著高于未施肥土壤（1.0 × 105 CFU/g）。此外，土壤真菌群落组成也存在差异。线虫放线菌（Actinomucor elegans）、黑孢镰刀菌（bionecia ochroleuca）、avenaceum镰刀菌（Fusarium equiseti）、oxysporum镰刀菌（Fusarium oxysporum）、solani镰刀菌（Fusarium solani）和Nectria sp.)在施肥土壤中占主导地位，它们的产N2O活性得到了证实。上述结果表明，农田表面施用颗粒有机肥后N2O排放主要由真菌反硝化作用引起。(C) 2013 Elsevier Ltd.版权所有。
Agricultural fields are one of the largest anthropogenic sources of atmospheric nitrous oxide (N2O). Fungi have been suggested to contribute substantially to N2O emission in terrestrial environments; however, the extent of the fungal contribution and the phylogenetic and physiologic nature of related fungal communities in agricultural fields are largely unknown. This study focused on the large N2O emission from cropland soil that occurs after granular organic fertilizers were applied to the surface. The granular organic fertilizers applied were evidently covered by fungal mycelia. An experiment using a soil microcosm was established to imitate the field observations. N2O emissions following surface organic fertilization were suppressed by 84 and 20% after the addition of cycloheximide (a fungal inhibitor) and streptomycin (a bacterial inhibitor), respectively, suggesting that fungi provide the main contribution to the observed N2O emission. The population density and community composition of fungi in the surface-fertilized and non-fertilized soils in the field were determined using colony counting, denaturing gradient gel electrophoresis and subsequent phylogenetic analyses. Thirty-four fungal strains were isolated from the soils, and their N2O producing activities were analyzed. Fungal population density in the surface-fertilized soil (2.6 x 10(6) CFU/g) was much higher than that in the non-fertilized soil (1.0 x 105 CFU/g). In addition, the fungal community compositions of the soils differed. Actinomucor elegans, Bionectria ochroleuca, Fusarium avenaceum, Fusarium equiseti, Fusarium oxysporum, Fusarium solani and Nectria sp. dominated the surface-fertilized soil, and their activity in producing N2O was confirmed. These results suggested that N2O emission after the surface application of granular organic fertilizers in the cropland field mainly resulted from fungal denitrification. (C) 2013 Elsevier Ltd. All rights reserved.