亚热带常绿阔叶林土壤磷素空间分布特征及其影响因素

摘要

Soil and litter sam ples were obtained at an equal distance in a one-hectare plot of a subtropical evergreen broadleafforest (Lithocarpus glaber-C yclobalanopsis glauca) in D ashanchong ForestPark in C hangsha county,H unan Province. Phosphorus(P) concentrations in soil, litter and thatch sam ples were analyzed to investigate the spatial distribution ofsoiltotalP and available P concentrations and theirdriving factors.The Pearson’s correlation analysis of totalP and available P in soils with the elevation,convexity,litterbiom ass,and totalP contents oflitterand thatch was performed. The results show ed that total P in soils at a depth of 0-30 cm ranged from 0.200 to 0.402 g/kg soil and available P were 2.2-6.7 mg/kg soil. Soil total P exhibited a strip distribution. The high values occurred at the low -elevation valleys,w hile the low values were found on the high-elevation ridges.The distribution ofsoilavailable P show ed in irregularpatch patterns.The totalsoilP had significant,negative correlationswith the elevation (p <0.001)and convexity (p=0.009),butdid notshow significantcorrelations with litterbiom ass and totalP contents oflitterand thatch. Soilavailable P,how ever,was less affected by terrain factors,and was mainly affected by litterbiom ass (r=0.263,p=0. 008)and totalP contentofthatch (r=0.238,p=0.017).%在湖南省长沙县大山冲国有林场的青冈-石栎常绿阔叶林样地内，用等距离布点法采集土壤和凋落物样品，分析常绿阔叶林内土壤（0-30 cm）、凋落物和腐殖质层的磷素（P）含量，研究土壤全 P 和有效 P 含量的空间分布特征；对土壤全 P 和有效 P 与海拔、凹凸度、凋落物生物量、凋落物全 P 含量和腐殖质层全 P 含量等因素进行相关分析，探讨土壤全 P 和有效 P 在亚热带常绿阔叶林中的分布状况及其形成原因。结果表明，土壤（0-30 cm）全 P 含量范围为0.200-0.402 g/kg，有效 P 含量为2.2-6.7 mg/kg。林地土壤全 P 含量呈条带状的梯度变化，高值区出现在海拔较低的沟谷洼地，低值出现在山脊地带；有效 P 含量则呈斑块状分布，无明显分布规律。林地土壤全 P 含量与海拔和凹凸度均具有极显著负相关（p<0.01），而凋落物生物量、凋落物全 P 含量及腐殖质层全 P 含量对其影响不显著。土壤有效 P 含量受地形因子的影响较小，其与凋落物生物量具有极显著正相关（p<0.01）、与腐殖质层全 P 含量具有显著正相关（p<0.05）。