Drying and rewetting effects on soil microbial community composition and nutrient leaching
Drying and rewetting effects on soil microbial community composition and nutrient leaching
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DOI：
10.1016/j.soilbio.2007.08.008
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发表时间：
2008-02-01
影响因子：
9.7
通讯作者：
Bardgett, Richard D.
中科院分区：
文献类型：
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作者：
Gordon, Helen;Haygarth, Philip M.;Bardgett, Richard D.
研究了干湿复湿事件（D/RW）对相邻不同管理强度草地土壤微生物特性和养分释放的影响。这两种草地分别为无施肥史的低生产力草地和有大量施肥史的高产草地，分别称为未改良草地和改良草地。磷脂脂肪酸分析（PLFA）结果表明，改良草地土壤微生物生物量显著高于改良草地，真菌丰度高于细菌丰度。两种草地土壤保持55%持水能力（WHQ）或干燥至10%持水能力，再湿润至55%持水能力，再湿润后的第1、3、9、16、30和50天采样。D/RW胁迫显著降低了两种土壤微生物生物量碳(C)、真菌PLFA和真菌PLFA比。相比之下，D/RW增加了微生物活性，但对两种土壤的总PLFA和细菌PLFA没有影响。D/RW显著降低了两种土壤的微生物生物量氮(N)，但以改良草地的减少幅度最大。在养分淋溶方面，D/RW胁迫显著提高了改良土壤浸出液中溶解有机C和溶解有机N的浓度。该处理增加了两种土壤渗滤液中溶解无机氮的浓度，但这种效果在改良土壤中最为明显。总体而言，我们的数据表明，D/RW胁迫导致改良草地土壤的养分淋失量大于未改良草地土壤，而未改良草地土壤的微生物生物量和真菌丰度高于细菌。这一发现支持了这样一种观点，即在D/RW下，真菌群落丰富的土壤比真菌与细菌比例较低的土壤能更好地保留养分，并且D/RW可以增强养分淋滤，从而对水质产生潜在影响。(c) 2007 Elsevier Ltd.版权所有。
The effects of a dry-rewetting event (D/RW) on soil microbial properties and nutrient release by leaching from two soils taken from adjacent grasslands with different histories of management intensity were studied. These were a low-productivity grassland, with no history of fertilizer application and a high-productivity grassland with a history of high fertilizer application, referred to as unimproved and improved grassland, respectively. The use of phospholipid fatty acid analysis (PLFA) revealed that the soil of the unimproved grassland had a significantly greater microbial biomass, and a greater abundance of fungi relative to bacteria than did the improved grassland. Soils from both grasslands were maintained at 55% water holding capacity (WHQ or dried to 10% WHC and rewetted to 55% WHC, and then sampled on days 1, 3, 9, 16, 30 and 50 after rewetting. The D/RW stress significantly reduced microbial biomass carbon (C), fungal PLFA and the ratio of fun gal-to- bacterial PLFA in both soils. In contrast, D/RW increased microbial activity, but had no effect on total PLFA and bacterial PLFA in either soil. Microbial biomass nitrogen (N) was reduced significantly by D/RW in both soils, but especially in those of the improved grassland. In terms of nutrient leaching, the D/RW stress significantly increased concentrations of dissolved organic C and dissolved organic N in leachates taken from the improved soil only. This treatment increased the concentration of dissolved inorganic N in leachate of both soils, but this effect was most pronounced in the improved soil. Overall, our data show that D/RW stress leads to greater nutrient leaching from improved than from unimproved grassland soils, which have a greater microbial biomass and abundance of fungi relative to bacteria. This finding supports the notion that soils with more fungal-rich communities are better able to retain nutrients under D/RW than are their intensively managed counterparts with lower fungal to bacterial ratios, and that D/RW can enhance nutrient leaching with potential implications for water quality. (c) 2007 Elsevier Ltd. All rights reserved.