Soil fertility promotes decomposition rate of nutrient poor, but not nutrient rich litter through nitrogen transfer
Soil fertility promotes decomposition rate of nutrient poor, but not nutrient rich litter through nitrogen transfer
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DOI：
10.1007/s11104-016-3072-1
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发表时间：
2017-03-01
期刊：
影响因子：
4.9
通讯作者：
Rao, Maria A.
中科院分区：
文献类型：
--
作者：
Bonanomi, Giuliano;Cesarano, Gaspare;Rao, Maria A.
凋落物分解是陆地生态系统中的一个重要过程，了解土壤肥力对凋落物分解速率的影响具有重要的生态意义。在这里，我们测试的假设，N从土壤转移到凋落物将促进N贫，但不是N丰富的凋落物types.Methods的衰减率，包括广泛的生化质量的C/N和木质素/N的比例，10个有机底物，分解在三个不同的N含量的土壤类型的缩影，但接种相同的微生物。有机基质的特点是质量损失，C和N含量，以评估N从土壤到litter.Results衰减率对土壤肥力的反应是有关其初始N含量：积极的基板，初始N含量少，并不显着的N丰富的植物残留物。凋落物C/N和木质素/N比值与凋落物分解呈不同程度的相关性，在富氮和贫氮土壤中，二者之间存在正相关和负相关，在低氮和高氮土壤中，二者之间存在正相关和负相关。结论富N凋落物的分解与土壤肥力无关，而贫N凋落物的分解速率与土壤肥力无关基质，无论是木质素贫乏或丰富，控制土壤肥力可能是由于氮转移。凋落物C/N和木质素/N比是贫氮土壤中凋落物质量的可靠指标，但在富氮土壤中不能预测凋落物的腐烂速率。
Background and aims Litter decomposition is a critical process in terrestrial ecosystems and understanding the effects of soil fertility on the litter decay rate is of great ecological relevance. Here we test the hypothesis that N transfer from soil to litter will promote the decay rate of N poor but not N rich litter types.Methods Ten organic substrates, encompassing a wide range of biochemical quality in terms of C/N and lignin/N ratios, were decomposed in microcosms over three soil types with different N content, but inoculated with the same microbiome. Organic substrates were characterized for mass loss, C and N content to assess N transfer from soil to litter.Results The decay rate response to soil fertility was related to their initial N content: positive for substrates with little initial N content and not significant for N rich plant residues. A significant N transfer, generally larger from N rich soil to N poor substrates, was found. Litter C/N and lignin/N ratios showed variable relationships with the litter decay according with the soil fertilitygradient, with positive and negative correlations in N rich and N poor soils, respectively.Conclusions Our study demonstrated that the decomposition of N rich litter proceeded irrespective of soil fertility while the decay rate of N poor substrates, either lignin poor or rich, was controlled by soil fertility likely as a result of N transfer. Litter C/N and lignin/N ratios were reliable indicators of litter quality to predict their decay rate in N poor soil, but not in N rich soils.