退化红壤重建森林初期细根特征及其作用机理研究

以江西泰和严重退化红壤上不同模式重建的森林第10年森林生态系统为对象，分析了细根分布特征及其与土壤性状相关性．结果表明,各重建森林模式的土壤细根主要分布在0～20 cm土层，占0～40 cm土层的73.39%～87.41%；不同重建森林模式细根的养分贮量有较明显差异，中等栽植密度晚松纯林细根的全N、全P和全K贮量远远高于其它林地，细根中全N、全P、全K、Ca、Mg贮量分别达84.47、5.55、38.42、17和10.76 kg·hm^-2；土壤有机质、全N、有效N、有效K、pH值与细根现存量相关显著(P<0.05)，细根对物理性状的影响主要体现在毛管孔隙度和总孔隙度上；植物细根显著提高了>5 mm土壤水稳性团聚体及>0.25 mm水稳性团聚体含量，从而增加了土壤结构的稳定性；土壤细根与土壤细菌和微生物总数相关性显著.

Fine-root character and its action mechanism of forest at its initial reestablished stage on degraded red soil

This paper studied the fine-root character and its action mechanism of forest reestablished by different models for 10 years on a seriously degraded red soil, and analyzed their correlation with soil property. The results showed that fine-roots mostly distributed in 0-20 cm soil layer, accounted for 73.39% -87.41% of those in 0-40 cm soil layer. There were notable differences in nutrient storage of fine-roots under different reestablishment models. The fine- roots of medium density pure Pinus serotina forest had a much higher storage of total nitrogen, phosphorus and potassium, with the content of total nitrogen, phosphorus, potassium, calcium and magnesium being 84.47, 5.55, 38.42, 17.00 and 10.76 kg hm(-2), respectively. Soil organic matter, total nitrogen, available nitrogen, available potassium and pH had significant correlations with fine-root biomass (P < 0.05). The effects of fine-roots on soil physical properties mainly reflected on soil capillary porosity and total porosity. Fine-roots obviously increased the contents of > 0.25 mm and > 5 mm soil waterstable aggregates, and improved soil structure-stability. The correlations between fine-roots and soil bacteria and microbial quantities were significant.