Decomposition of nitrogen-15 labeled hoop pine harvest residues in subtropical Australia
Decomposition of nitrogen-15 labeled hoop pine harvest residues in subtropical Australia
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DOI：
10.2136/sssaj2004.1751
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发表时间：
2004-09-01
影响因子：
2.9
通讯作者：
Saffigna, PG
中科院分区：
文献类型：
--
作者：
Blumfield, TJ;Xu, ZH;Saffigna, PG
采伐剩余物分解的信息可能有助于维持第二轮（2 R）箍松人工林（南洋杉艾顿ex A.狡猾。）产于亚热带澳大利亚。本试验旨在研究秸秆分解的动力学和秸秆源氮的去向。我们使用N-15标记箍松叶，分支，茎材料在微区，在30个月的时间收获后。我们研究了每个组件的分解单独和组合，并使用C-13交叉极化和魔角旋转核磁共振（C-13 CPMAS NMR）图表C变换分解树叶。残留物衍生的N-15被固定在0至5厘米的土壤层，约40%的N-15在土壤中的回收率从结合残留物的30个月期间结束。残留物和土壤中N-15的总回收率在60 - 80%之间变化，结合残留物微区，20 - 40%的残留物N-15明显丢失。当残留物结合在微小区内的树叶分解率下降了30%，而分支和茎分解率增加了50%和40%，这些组件分别分解时的速率相比。残留物分解研究应包括混合残留物处理。利用C-15 CPMAS NMR谱对落叶腐解产物进行分析，得到了甲氧基碳、芳基碳、碳水化合物碳和酚类碳与残体质量、N-15富集量和全N的良好相关性。碳水化合物C与甲氧基C的比值可作为箍松林采伐残留物分解的指标。
Information on decomposition of harvest residues may assist in the maintenance of soil fertility in second rotation (2R) hoop pine plantations (Araucaria cunninghamii Aiton ex A. Cunn.) of subtropical Australia. The experiment was undertaken to determine the dynamics of residue decomposition and fate of residue-derived N. We used N-15-labeled hoop pine foliage, branch, and stem material in microplots, over a 30-mo period following harvesting. We examined the decomposition of each component both singly and combined, and used C-13 cross-polarization and magic-angle spinning nuclear magnetic resonance (C-13 CPMAS NMR) to chart C transformations in decomposing foliage. Residue-derived N-15 was immobilized in the 0- to 5-cm soil layer, with approximately 40% N-15 recovery in the soil from the combined residues by the end of the 30-mo period. Total recovery of N-15 in residues and soil varied between 60 and 80% for the combined-residue microplots, with 20 to 40% of the residue N-15 apparently lost. When residues were combined within microplots the rate of foliage decomposition decreased by 30% while the rate of branch and stem decomposition increased by 50 and 40% compared with rates for these components when decomposed separately. Residue decomposition studies should include a combined-residue treatment. Based on C-15 CPMAS NMR spectra for decomposing foliage, we obtained good correlations for methoxyl C, aryl C, carbohydrate C and phenolic C with residue mass, N-15 enrichment, and total N. The ratio of carbohydrate C to methoxyl C may be useful as an indicator of harvest residue decomposition in hoop pine plantations.