不同密度格木幼林的土壤理化与林下植被特征

为探索适合格木(Erythrophleum fordii)人工林在幼龄阶段的种植密度，在不同林分密度(2 m×1 m、2 m×2 m、2 m×3 m、3 m×3 m)的6 a生格木人工林下设置标准样地，采用土壤质量评价和灰色关联度等方法，探究不同密度下格木幼林的土壤理化与林下植被特征。结果表明，密度2 m×3 m下的林木胸径、树高最优，较最低水平高16.7%、27.9%；土壤总孔隙度最大，全N、硝态N、铵态N含量最高，灌木草本多样性最高。相关性分析表明土壤化学性质对灌木草本的多样性影响最大。不同林分密度下格木幼林土壤理化性质及林下植物多样性有显著差异，因此，选择合适的林分密度对人工林土壤肥力的可持续利用及林分的经营培育至关重要。

Characteristics of Soil Physicochemistry and Understory Vegetation in Young Plantation of Erythrophleum fordii Under Different Densities

To explore the suitable density for young plantations of Erythrophleum fordii, standard plots were set in 6-year-old Erythrophleum fordii plantation with different densities (2 m×1 m, 2 m×2 m, 2 m×3 m, 3 m×3 m), the characteristics of soil physicochemistry and understory vegetation in young plantation were studied by using soil quality evaluation and grey correlation method. The results showed that the DBH and height of trees under the density of 2 m×3 m were optimal, which were 16.7% and 27.9% higher than the lowest level, and the total porosity, total N, nitrate N and ammonium N contents of soil, as well as shrub and herb diversities also were the highest. After analyzing the correlation between soil physical and chemical properties and plant diversity, soil chemical properties had the greatest influence on shrub and herb diversity. There were significant differences in soil physical and chemical properties and understory plant diversity of E. fordii plantation among different stand densities. Therefore, it was very important to select appropriate density for the sustainable utilization of soil fertility, management and cultivation of plantations.