Short and long-term effects of elevated CO2 on Lolium perenne rhizodeposition and its consequences on soil organic matter turnover and plant N yield
Short and long-term effects of elevated CO2 on Lolium perenne rhizodeposition and its consequences on soil organic matter turnover and plant N yield
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DOI：
10.1016/j.soilbio.2005.10.002
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发表时间：
2006-06-01
影响因子：
9.7
通讯作者：
Soussana, J. F.
中科院分区：
文献类型：
--
作者：
Allard, V.;Robin, C.;Soussana, J. F.
目前尚不清楚CO2浓度升高是否会增加植物根系分泌，从而影响土壤微生物生物量。CO2浓度升高对老土壤有机质库中C和N的去向的影响也不清楚。在这项研究中，短期和长期的CO2浓度升高对C和N库和通量的影响进行了评估，在温室中的高浓度和环境大气CO2和使用的土壤从新西兰FACE网站，有超过4年的暴露于CO2富集的分离植物的黑麦草（Lolium perenne）。利用（CO2）-C-14脉冲标记技术，研究了CO2浓度升高对植物-土壤系统中C分配的影响。在CO2浓度升高的情况下，在标记后48 h，在土壤和微生物生物量中发现了更多的根源性C。基质有效性的增加显着刺激土壤微生物的生长，并作为启动效应，促进原生土壤有机质的分解，无论矿质氮供应。尽管有迹象表明，在CO2浓度升高的土壤中的N循环更快，但植物的N可用性保持不变。土壤以前暴露于CO2浓度升高表现出较高的N循环速率，但再次有植物N吸收没有影响。关于。尽管将温室实验结果外推到田间存在困难，但我们得出结论，在CO2浓度升高的情况下，田间观察到的粗有机物的积累可能不是由C和N之间的不平衡造成的，而是可能是由于涉及土壤中型动物和/或其他养分限制的更复杂的现象。(c)2005爱思唯尔有限公司保留所有权利。
It is still unclear whether elevated CO2 increases plant root exudation and consequently affects the soil microbial biomass. The effects of elevated CO2 on the fate of the C and nitrogen (N) contained in old soil organic matter pools is also unclear. In this study the short and long-term effects of elevated CO2 on C and N pools and fluxes were assessed by growing isolated plants of ryegrass (Lolium perenne) in glasshouses at elevated and ambient atmospheric CO2 and using soil from the New Zealand FACE site that had > 4 years exposure to CO2 enrichment. Using (CO2)-C-14 pulse labelling, the effects of elevated CO2 on C allocation within the plant-soil system were studied. Under elevated CO2 more root derived C was found in the soil and in the microbial biomass 48 h after labelling. The increased availability of substrate significantly stimulated soil microbial growth and acted as priming effect, enhancing native soil organic matter decomposition regardless of the mineral N supply. Despite indications of faster N cycling in soil under elevated CO2, N availability to plants stayed unchanged. Soil previously exposed to elevated CO2 exhibited a higher N cycling rate but again there was no effect on plant N uptake. With respect to. the difficulties of extrapolating glasshouse experiment results to the field, we concluded that the accumulation of coarse organic matter observed in the field under elevated CO2 was probably not created by an imbalance between C and N but was likely to be due to more complex phenomena involving soil mesofauna and/or other nutrients limitations. (c) 2005 Elsevier Ltd. All rights reserved.