Feedback interactions between needle litter decomposition and rhizosphere activity
Feedback interactions between needle litter decomposition and rhizosphere activity
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DOI：
10.1007/s00442-004-1540-4
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发表时间：
2004-03
期刊：
影响因子：
2.7
通讯作者：
J. Subke;V. Hahn;G. Battipaglia;S. Linder;N. Buchmann;M. F. Cotrufo
中科院分区：
文献类型：
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作者：
J. Subke;V. Hahn;G. Battipaglia;S. Linder;N. Buchmann;M. F. Cotrufo
本研究的目的是确定地上凋落物分解与根际活动之间的相互作用。实验方法将标记凋落物（δ13C=−37.9‰）放置与森林围育相结合，得到GL（围育，凋落物）、GNL（围育，无凋落物）、NGL（不围育，凋落物）和NGNL（不围育，无凋落物）4种不同的处理组合。2002年5月至10月间每月对土壤co2流出量和土壤呼吸co2的δ13C进行采样，将通量划分为来自标记凋落物的通量和来自原生土壤有机质和根系的通量。森林围篱对土壤co2通量的影响从6月开始（围篱发生在4月），到8月下旬，GNL通量约为NGNL通量的50%。在试验的前2个月，凋落物的存在导致了通量的显著增加，而在同一时期，非围育地块的凋落物衍生通量显著增加，围育和凋落物处理之间存在显著的相互作用。对于NGL项圈，发现额外的外排仅部分来自凋落物分解，但也来自原生土壤有机质的腐烂。在GL衣领中，这种启动效应不显著，表明根际在土壤启动中起积极作用。因此，研究结果表明凋落物分解与根际活性之间存在着相互的正反馈关系。土壤生物分析（微生物和真菌生物量）表明，在NGL领以下有机质层的活性最大，我们认为这种增加表明了根际活性与凋落物分解之间的相互正反馈机制。然而，与NGNL处理相比，消除来自地上和地下（GNL）的新鲜C输入也导致了更高的真菌丰度，这表明真菌群落结构可能发生了变化。A3B2显示$132#?>e。从共生到腐坏物种丰度的转变)。
The aim of our study was to identify interactions between the decomposition of aboveground litter and rhizosphere activity. The experimental approach combined the placement of labelled litter (δ13C=−37.9‰) with forest girdling in a 35-year-old Norway spruce stand, resulting in four different treatment combinations: GL (girdled, litter), GNL (girdled, no litter), NGL (not girdled, litter), and NGNL (not girdled, no litter). Monthly sampling of soil CO2efflux and δ13C of soil respired CO2between May and October 2002 allowed the partitioning of the flux into that derived from the labelled litter, and that derived from native soil organic matter and roots. The effect of forest girdling on soil CO2efflux was detectable from June (girdling took place in April), and resulted in GNL fluxes to be about 50% of NGNL fluxes by late August. The presence of litter resulted in significantly increased fluxes for the first 2 months of the experiment, with significantly greater litter derived fluxes from non-girdled plots and a significant interaction between girdling and litter treatments over the same period. For NGL collars, the additional efflux was found to originate only in part from litter decomposition, but also from the decay of native soil organic matter. In GL collars, this priming effect was not significant, indicating an active role of the rhizosphere in soil priming. The results therefore indicate mutual positive feedbacks between litter decomposition and rhizosphere activity. Soil biological analysis (microbial and fungal biomass) of the organic layers indicated greatest activity below NGL collars, and we suppose that this increase indicates the mechanism of mutual positive feedback between rhizosphere activity and litter decomposition. However, elimination of fresh C input from both above- and belowground (GNL) also resulted in greater fungal abundance than for the NGNL treatment, indicating likely changes in fungal community structure (i.<?A3B2 show $132#?>e. a shift from symbiotic to saprotrophic species abundance).