火烧对大兴安岭落叶松天然林土壤团聚体有机碳和黑碳的影响

发布时间：2018-09-07 19:49

【摘要】：为了揭示不同强度火烧对大兴安岭落叶松天然林土壤团聚体有机碳和黑碳的影响,本文选取大兴安岭落叶松天然林重度、中度、轻度火烧迹地为研究对象,并以未火烧落叶松天然林为对照,进行相关研究,结果表明：(1)土壤有机碳和黑碳具有明显的表聚特征,0-5 cm层全土有机碳和黑碳含量显著高于5-10和10-20 cm层(P0.05.)。重度火烧明显增加表层土壤有机碳和黑碳含量。和对照样地相比,在0-5 cm层,重度火烧迹地全土有机碳增加了41.56%,黑碳增加了156.44%,黑碳含量增加显著(P0.05)：中度火烧迹地有机碳含量降低了6.63%,黑碳增加了46.85%,黑碳含量差异显著(P0.05)；轻度火烧迹全土有机碳和黑碳没有明显变化。说明重度火烧对土壤有机碳和黑碳含量的影响较大,主要在0-5 cm层。(2)大兴安岭落叶松天然林土壤干筛团聚体和水稳性团聚体以2mm级为主,经不同强度火烧,团聚体组成特征表现出异质趋向,干筛团聚体和水稳性团聚体PAo.25表现出降低的趋势,PADo.25和D表现出增大的趋势,主要表现在表层土壤。水稳性团聚体的比表面积(MWSSA)随火烧强度增加而降低,为155.60～169.27 cm2/g,是干筛处理的4倍左右。水稳性团聚体的MWSSA随火烧强度的变化规律与干筛处理相反。说明不同强度的火烧降低了团聚体的团聚作用,降低了土壤的机械稳定性和水稳性,重度和中度火烧表现尤为明显。(3)4种林型各粒径干筛团聚体有机碳含量表现为随粒径增大而增加,随土层深度的增加而降低的趋势。同对照样地相比,重度火烧显著提高了0～5 cm土层内5mm和0.053 mm团聚体有机碳含量(P0.05),增幅达177.76%和127.27%。而0.25～2 mm团聚体有机碳含量在3个土层内较对照均有不同程度的降低,中度与轻度火烧迹地干筛团聚体有机碳含量变化与重度火烧迹地相似。重度火烧增加了0-5 cm层各级水稳性团聚体有机碳含量,而中度、轻度火烧迹地各粒径水稳性团聚体有机碳含量变化不明显。(4)干筛团聚体中黑碳的分布规律与有机碳相似。重度火烧迹地0-5 cm层5mm、2～5 mm、0.053～0.25 mm、＜0.053 mm干筛团聚体黑碳含量分别增加了4.92、4.19、1.06、0.44 g/kg,与对照之间的差异均达显著水平(P0.05)。中度和轻度火烧迹地干筛团聚体黑碳含量变化与重度火烧迹地相似。重度火烧明显增加了三个土层各粒径水稳性团聚体黑碳含量(P0.05),中轻度火烧迹地水稳性团聚体黑碳含量变化较小。(5)各级团聚体BC/SOC比值在0.05～0.45之间,且不同强度火烧明显增加了各级干筛团聚体和水稳性团聚体的BC/SOC比值。(6)相关分析表明,全土有机碳和黑碳以及各粒径干筛团聚体有机碳和黑碳含量之间有显著的线性关系,而水稳性团聚体有机碳和黑碳之间线性相关性较低。
[Abstract]:In order to reveal the effects of different burning intensities on soil aggregates organic carbon and black carbon in Larix gmelinii natural forest, the heavy, moderate and light burned areas of Larix gmelinii natural forest were selected as the research objects, and the unfired Larix gmelinii natural forest as the control, the results showed that: (1) Soil organic carbon and black carbon were correlated. The contents of organic carbon and black carbon in 0-5 cm layer soil were significantly higher than those in 5-10 and 10-20 cm layers (P (P 0.05): The content of organic carbon decreased by 6.63%, black carbon increased by 46.85%, black carbon content was significantly different (P 0.05); the content of organic carbon and black carbon had no significant change in the whole soil of light burning. Dry-sieve aggregates and water-stable aggregates were mainly of 2mm grade, and the compositions of aggregates showed heterogeneous tendency after different burning intensities. Dry-sieve aggregates and water-stable aggregates PAo.25 showed a decreasing trend, while PADo.25 and D showed an increasing trend, mainly in surface soil. Specific surface area (MWSSA) of water-stable aggregates increased with fire. The variation of MWSSA of water-stable aggregates with fire intensity was contrary to that of dry sieve treatment. The results showed that the agglomeration of aggregates was reduced by different intensity of fire, and the mechanical stability and water stability of soil were decreased, especially in severe and moderate fire. (3) The organic carbon content of dry sieve aggregates increased with the increase of grain size and decreased with the increase of soil depth. Compared with the control plots, the organic carbon content of 5 mm and 0.053 mm aggregates in 0-5 cm soil layers increased significantly (P 0.05), with an increase of 177.76% and 127.27%. The content of organic carbon in dry-sifted aggregates in moderate and light burning sites was similar to that in severe burning sites. The content of organic carbon in water-stable aggregates in 0-5 cm layers was increased by severe burning, while that in water-stable aggregates in moderate and light burning sites was increased by moderate and light burning. (4) The distribution of black carbon in dry-sieve agglomerates was similar to that of organic carbon. The black carbon content of 0-5 cm layer, 2-5 mm, 0.053-0.25 mm, 0.053 mm and < 0.053 mm dry-sieve agglomerates increased by 4.92, 4.19, 1.06, 0.44 g/kg, respectively, and the difference between the two groups was significant (P 0.05). The change of black carbon content of aggregates was similar to that of heavy burning. The heavy burning significantly increased the black carbon content of water-stable aggregates with different particle sizes in three soil layers (P 0.05), and the change of black carbon content of water-stable aggregates with moderate and light burning was small. (5) The BC/SOC ratio of all kinds of aggregates ranged from 0.05 to 0.45, and the different burning intensities significantly increased the dryness of all grades. (6) Correlation analysis showed that there was a significant linear relationship between organic carbon and black carbon in the whole soil and the content of organic carbon and black carbon in the dry-sieve aggregates with different sizes, while the linear correlation between organic carbon and black carbon in the water-stable aggregates was lower.
【学位授予单位】：东北林业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S714.2

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