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首页> 外文期刊>Soil Science Society of America Journal >Formation and Loss of Humic Substances During Decomposition in a Pine Forest Floor
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Formation and Loss of Humic Substances During Decomposition in a Pine Forest Floor

机译：松林地上腐殖过程中腐殖质的形成与损失

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Since twice as much C is sequestered in soils as is contained in the atmosphere, the factors controlling the decomposition rate of soil C are important to the assessment of the effects of climatic change. The formation of chemically resistant humic substances might be an important process controlling recycling of CO2 to the atmosphere. Our objectives were to measure the rate of formation and loss of humic substances during 13 yr of litter decomposition. We placed nets on the floor of a white pine (Pinus strobus) forest to separate each annual layer of litter for 13 yr and measured humic substance concentration using NaOH extraction followed by chromatographic fractionation. The humic acid fraction increased from 2.1% of the C in litterfall to 15.7% after 1 yr. On a grams per square meter (g m-2) basis the humic substance fraction increased during the first year and then declined, with a half decay time (t1/2) of 5.1 yr, which was significantly slower than the bulk litter (t1/2 = 3.9 yr). The carboxylic C concentration estimated from 13C nuclear magnetic resonance (NMR) increased in the litter over time, though total mass of carboxylic acid C in the forest floor also declined over the 13-yr period (t1/2 = 4.6 yr). While humic substances in the forest floor decomposed at a somewhat slower rate than bulk litter during Years 1 to 13, they decomposed much faster than has been calculated from 14C dating of the refractory fraction of organic matter in the mineral soil.
机译：由于固存在土壤中的碳的含量是大气中所含 的两倍，因此控制土壤C分解 速率的因素对于评估影响 气候变化。耐化学腐殖质 物质的形成可能是控制CO 2 循环到大气中的重要过程。我们的目标是测量凋落物分解的13年 中腐殖质形成和损失的速率。我们将蚊帐放在白色松树（Pinus strobus）森林的地板上，以分隔每年每 枯枝落叶层13年，并测量腐殖质浓度 使用NaOH提取，然后进行色谱分离。 1年后，腐殖酸含量从凋落物中的2.1％增加到15.7％。在每克克数（gm -2 ）的基础上， 第一年腐殖质含量 然后下降，下降了一半。时间（t 1/2 ）为5.1年， 比散装垃圾（t 1/2 = < /sup>3.9年）。根据 13 C核 磁共振（NMR）估算的羧酸C浓度随时间的推移随垫料的增加而增加， 在13年期间（t 1/2 = 4.6年），森林地层也 下降。尽管林地中的腐殖质 在1至13年间的分解速度 比散装垃圾慢，但它们分解 的速度却比以前快得多。 矿物质土壤中有机质的难熔部分的 14 C测年得出的。

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