六盘山林区土壤物理性质分布特征

Distribution of soil physical properties in forest of Liupan Mountains

研究了六盘山林区土壤物理性质分布特征及其与海拔和林型的关系，结果表明：六盘山林区阔叶林地土壤有机质和饱和导水率显著高于针叶林地，土壤容重显著低于针叶林地，阔叶林地0～10 cm和10～20 cm土层土壤有机质和饱和导水率分别比针叶林地高27．7％、21．2％和38．0％、42．2％，容重比针叶林地低13．8％和7．6％；高海拔处林地土壤有机质含量较高，容重较低；研究区土壤饱和导水率不受海拔影响，土壤水稳性团聚体分布不受林型和海拔的影响；阔叶林地0～20 cm土层土壤平均重量直径和几何平均直径平均值分别比针叶林地高3．46％和5．21％，但不受海拔影响，大团聚体数量与饱和导水率极显著正相关。研究表明六盘山林区阔叶林地土壤物理性状显著优于针叶林地，林地土壤结构的改良主要体现在大团聚体增加方面。

The objectives of this study were to explore the distribution of soil physical properties and their influenc-ing factors in forest of the Liupan Mountains .The distribution of major soil properties in forest of Liupan Mountains ,and the relationships between soil physical properties ,elevation and forest species were studied .Additionally ,the relation-ships among soil physical properties were analyzed .The results showed that the contents of organic matter and saturated hydraulic conductivity were significantly higher in soils under broadleaf forest than those under conifer forest ,but the bulk density was lower in soils under broadleaf forest than that under conifer forest .The organic matter content and saturated hydraulic conductivity in broadleaf forest were 27 .7% and 21 .2% higher in 0~10 cm and 10~20 cm depth ,and 38%and 42 .2% higher in 0~10 cm and 10~20 cm depth ,respectively ,than those in conifer forest .However ,the soil bulk densities under broadleaf forest in 0~10 cm and 10~20 cm depth were 13 .8% and 7 .6% lower than those under conifer forest ,respectively .Further ,organic matter content was relatively higher ,while bulk density was relatively lower in soils at higher elevation than those in lower elevation conditions .Besides the saturated hydraulic conductivity was not affected by elevation conditions .The mean values of MWD and GMD through 0~20 cm depth were 3 .46% and 5 .21%higher in broadleaf soils than conifer soils ,respectively .But they were unaffected by elevation conditions .Correlation analysis revealed that the amount of macroaggregate was signifcantly positively correlated with saturated hydraulic conduc-tivity .This finding indicated that the physical properties of soils under broadleaf forest were better than those under conifer forest in the Liupan Mountain region by the increasing amount of macroaggregate .