诱导改造对大兴安岭低质林土壤理化性质的影响

2009年对大兴安岭地区的阔叶混交次生林及白桦萌生低质林进行不同带宽皆伐,将每条皆伐带分为3段,分别种植西伯利亚红松、落叶松和樟子松,2011年8月测定林分的土壤理化指标。结果表明:不同方式改造后土壤密度均不同程度地降低,而土壤毛管持水量、毛管孔隙度均不同程度地升高;与对照样地相比,阔叶混交次生林不同诱导改造后土壤全氮含量均升高(落叶松林升高98.26%,西伯利亚红松林升高72.70%,樟子松林升高44.91%),除落叶松林土壤全磷含量3.35g·kg-1保持不变外,西伯利亚红松林和樟子松林全磷含量均降低;与对照样地相比,白桦萌生低质林不同诱导改造后土壤全磷、全氮含量均有所降低,全磷含量降低程度表现为西伯利亚红松林降低38.90%、落叶松林降低33.15%、樟子松林降低11.78%,全氮含量降低程度表现为西伯利亚红松林降低36.02%、落叶松林降低36.75%、樟子松林降低37.68%;综合分析所有改造林,土壤有机质含量与全氮、全钾含量显著正相关(P﹤0.05);不同带宽西伯利亚红松林的土壤pH值、有机质含量、全氮含量及全钾含量变异系数最大,说明带宽对西伯利亚红松诱导林土壤理化性质有显著影响。

Impacts of Different Induced Transformation on Soil Physical and Chemical Properties of Low-Quality Forest in the Daxing'an Mountains

Clearcutting with varied width was carried out in a secondary growth mixed broadleaved forest and a low-quality birch coppice forest in the Daxing’an Mountains in 2009. Each cutting strip was divided into three sections. Pinus sibirica, Larix gmelinii and Pinus sylvestris var.mongolica were planted in each section, respectively. Soil physical and chemical properties were then analyzed in August, 2011. Results showed that soil density reduced while soil capillary water holding capacity and capillary porosity increased after clearcutting. Compared to the control site, soil total nitrogen increased in the whole experimental site in the mixed broadleaved forest(98.26%, 72.70%, and 44.91% increase in the larch forest, Siberian Korean pine forest and Mongolica pine forest, respectively). Soil total phosphorus decreased for both Siberian Korean pine and the Mongolica pine forests while it remains contant of 3.35 g·kg-1 in Larch forest. In comparison with the control site, both soil total nitrogen and total phosphorus decreased to a various degree. The soil total phosphorus decreased 38.90%, 33.15%, and 11.78% for Siberian Korean pine forest, Larch forest, and Mongolica pine forest, respectively. The soil total nitrogen decreased 36.02%, 36.75%, and 37.68% for Siberian Korean pine forest, Larch forest, and Mongolica pine forest, respectively. Generally, there was a significant positve correlation(P﹤0.05) between the soil organic matter content and soil total nitrogen and total potassium. The soil pH value, organic matter content, total nitrogen and total potassium content had the largest variation coefficient in Siberian Korean pine forest over different cutting widths, which suggested that cutting width had significant effects on soil physical and chemical properties of the induced Siberian Korean pine forest.