不同林龄长白落叶松人工林土壤肥力

Soil Fertility in Korean Larch Plantations of Different Stand Age

基于吉林省汪清林业局金仓林场中15～52年生长白落叶松(Larix olgensis Herry.)人工林土壤肥力调查数据,分析和比较了不同林龄长白落叶松人工林的土壤物理和化学性质,并采用主成分分析评价了其土壤肥力状况。结果表明:①林龄对长白落叶松人工林土壤理化性质影响显著,随着林龄的增加,土壤密度和土壤pH值先降低后增加,而土壤含水量和养分质量分数先增加后减少,但其在不同林龄下的变化程度不同;②土壤肥力因子之间关系密切,土壤密度与含水量、有机质、全氮、全磷、速效钾呈极显著负相关,而与土壤pH值呈显著正相关;土壤养分质量分数之间具有不同程度的显著正相关关系;③采用主成分分析法对不同林龄长白落叶松人工林土壤肥力状况进行了评价,土壤肥力状况由高到低为:中龄林、幼龄林、成熟林、近熟林。建议在经营现有的长白落叶松人工林时,注意调整幼龄林和中龄林林分密度,控制近熟林和成熟林的采伐强度,及时进行林下补植更新,并营造针阔混交林,以改善长白落叶松人工林土壤的肥力状况。

An investigation was conducted to study and evaluate soil fertility in Korean larch plantations of different ages ranging from 15 to 52 years old in Jincang Forest Farm of Jilin Province. The soil physico-chemical properties were carried out in larch plantations of different stand ages. Soil fertility of these stands was further assessed by principal component analysis method. The results show that the stand age has significant effects on soil physico-chemical properties. With the increase of stand age, the soil bulk density and the soil pH firstly increase and then decrease, but the soil water content and the nu- trient content change with diverse variation degrees in larch plantations of different stand ages. There are close correlations between soil properties. Soil moisture content, soil organic matter, total N, total P and rapidly available K had very signif- icant negative correlations with soil bulk density, but significant positive correlations with soil pH. The correlations be- tween soil nutrient contents are significant positive, but in different degrees. The soil fertility assessment by principal com- ponent analysis shows soil fertility order of Korean ]arch plantation： middle-age forest〉young forest〉mature forest〉nearly mature forest. Therefore, adjusting stand density of young forest and middle-age forest, controlling cutting intensity and replanting nearly mature forest and mature forest with long-term located observations are the suggested methods to improve the general soil fertility of Korean larch plantations.