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树种通过改变凋落物输入与周转及根系活动影响土壤的理化和生物学性质及固碳功能。合理选择树种是碳汇林业中一个亟待解决的理论和实践问题。为了减少林分特征和立地条件差异的影响,2004年在相同气候、土壤和经营历史的立地上建立了东北地区常见树种同质园,10年(2013–2014年)后测定了其中的3种阔叶树(白桦(Betula platyphylla)、胡桃楸(Juglans mandshurica)、水曲柳(Fraxinus mandshurica))和两种针叶树(落叶松(Larix gmelinii)、樟子松(Pinus sylvestris var.mongolica))人工纯林的土壤有机碳(SOC)及土壤容重、全氮、微生物生物量碳、微生物生物量氮、p H值等相关因子,旨在比较探索树种对SOC含量及其垂直分布的影响。结果表明:(1)树种显著影响0–40 cm土层SOC总密度(p<0.05)。其中,0–10 cm土层SOC密度变化范围为2.79–3.08 kg·m–2,表现为胡桃楸林>水曲柳林>白桦林>落叶松林>樟子松林;10–20 cm土层变化范围为1.56–2.19kg·m–2,表现为樟子松林>胡桃楸林>水曲柳林>白桦林>落叶松林;20–30 cm土层变化范围为1.17–2.10 kg·m–2,表现为白桦林、水曲柳林显著高于其他树种纯林;30–40 cm土层变化范围为0.84–1.43 kg·m–2,表现为白桦林显著高于其他树种纯林。(2)SOC密度垂直分布格局因树种和土层而异。胡桃楸林、落叶松林0–10 cm土层SOC密度占0–40 cm土层总密度的相对量显著高于其他树种纯林,白桦林20–40 cm土层的SOC密度相对量显著高于其他树种纯林,这说明不同层次SOC密度的主控因子因树种而异。(3)不同树种纯林SOC浓度、容重差异显著,且两者呈负相关。胡桃楸林、水曲柳林和落叶松林SOC密度与土壤微生物生物量、土壤p H值均呈正相关关系。5个树种纯林SOC密度均与全氮密度呈正相关关系。研究表明,树种通过改变土壤理化性质和微生物活动而显著影响SOC密度,不同树种SOC密度垂直变化格局可能是由不同树种在各个土层中的SOC密度主控因素不同所致。
Species affected soil physicochemical and biological properties and carbon sequestration by altering litter input and turnover and root activity. Reasonable choice of species is a theoretical and practical problem to be solved in carbon sink forestry. In order to reduce the impact of differences in stand characteristics and site conditions, a common tree species homogenate in northeastern China was established on the site of the same climate, soil and operating history in 2004. Three of these species were determined after 10 years (2013-2014) (Betula platyphylla, Juglans mandshurica, Fraxinus mandshurica) and two types of conifer (Larix gmelinii, Pinus sylvestris var. Mongolica) Soil organic carbon (SOC) and soil bulk density, total nitrogen, microbial biomass carbon, microbial biomass nitrogen, p H value and other related factors were compared to explore the effect of species on the SOC content and its vertical distribution. The results showed that: (1) Species significantly affected SOC total density in 0-40 cm soil layer (p <0.05). Among them, the range of SOC density in 0-10 cm soil layer ranged from 2.79 to 3.08 kg · m-2, which represented as Juglans mandshurica> Fraxinus mandshurica> Betula platyphylla forest> Larix gmelinii forest> Pinus sylvestris var. Mongolica. Ranged from 1.56 to 2.19 kg · m-2, showing Pinus sylvestris> Juglans mandshurica> Fraxinus mandshurica> Betula platyphylla forest> Larix gmelinii forest. The range of 20-30 cm soil layer was 1.17-2.10 kg · m-2, The results showed that the Betula platyphylla and Quercus mongolica were significantly higher than the pure forests of other species; the range of 30-40 cm soil layer was 0.84-1.43 kg · m-2, which showed that the Betula platyphylla was significantly higher than the pure forest of other species. (2) The vertical distribution of SOC density varies with tree species and soil layers. Compared with pure forest of other species, the relative density of SOC density in 0-40 cm layer of 0-10 cm soil layer in Juglans mandshurica forest and Larix gmelinii forest was significantly higher than that of other tree species. The relative density of SOC density in 20-40 cm layer of Betula platyphylla forest was significantly higher Other species of pure forest, indicating that different levels of SOC density of the main control factors vary with species. (3) There was a significant difference in SOC concentration and bulk density among different tree species, and the two were negatively correlated. The SOC density of Juglans mandsulata forest, Manchurian ash forest and Larix gmelinii forest had a positive correlation with soil microbial biomass and soil p H value. The SOC density of five tree species pure forests was positively correlated with total nitrogen density. The results showed that tree species significantly affected SOC density by changing soil physico-chemical properties and microbial activities. The vertical variation of SOC density of different tree species was probably caused by the different controlling factors of SOC density in different soil layers.