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以华北落叶松人工林为对象,研究不同林分密度下(分别为740、1480、2000和2170株.hm-2)各土层的土壤有机碳含量、有机碳密度、养分特征以及它们之间的相关关系。结果表明:土壤有机碳含量及碳密度随着土壤深度增加而减少,呈明显的垂直分布特征;当林分密度增大到2170株.hm-2时,土壤有机碳含量及碳密度显著增加至最大,分别为25.45g.kg-1和15.68kg.m-2,并与740株.hm-2林地土壤有机碳含量及碳密度差异显著。当林分密度由740株.hm-2增加到2170株.hm-2时,各种养分变化规律不尽一致,但当林分密度为2170株.hm-2时,0-60cm深度的土壤全氮、全磷及速效钾含量均保持在一个相对较高的水平,而土壤全钾和有效磷含量仅在0-20cm土层较高。对于落叶松人工林地整个土壤剖面,土壤有机碳含量及碳密度与土壤全氮、全磷、速效钾含量均呈显著或极显著正相关。从林地土壤固碳的角度,建议将华北落叶松人工林的林分密度控制在2170株.hm-2。
The Larix principis-rupprechtii plantation was used to study the characteristics of soil organic carbon (SOC), organic carbon (SOC) and nutrient contents in different soil layers (740, 1480, 2000 and 2170.hm-2) The relationship between. The results showed that soil organic carbon content and carbon density decreased with the increase of soil depth, showing a vertical distribution. When the stand density increased to 2170 plants.hm-2, the soil organic carbon content and carbon density increased significantly The maximum values were 25.45g.kg-1 and 15.68kg.m-2, respectively, which were significantly different from the soil organic carbon content and carbon density of 740 plant species .hm-2. When the stand density was increased from 740 hm-2 to 2170 hm-2, the variation of various nutrients was not uniform. However, when the stand density was 2170 hm-2, Total nitrogen, total phosphorus and available potassium content were maintained at a relatively high level, while soil total potassium and available phosphorus content in 0-20cm soil layer only higher. For the whole soil profiles of Larix gmelinii plantations, there was a significant or very significant positive correlation between soil organic carbon content and carbon density and soil total nitrogen, total phosphorus and available potassium. From the perspective of soil carbon sequestration in the forest, it is proposed to control the stand density of Larix principis-rupprechtii plantation at 2170 plants.hm-2.