摘要
为掌握立地条件对樟子松(Pinus sylvestris var.mongolica)人工林土壤生态化学计量的影响,以浑善达克沙地不同坡向、坡度、坡位上的林龄12 a樟子松人工林为研究对象,测定0～50 cm土层土壤物理性质及土壤C、N、P等化学计量,研究其垂直分布特征及在不同立地条件的变化规律.结果表明:(1)平坡、阳向缓坡、阴向缓坡、阳向斜坡、阴向斜坡、阳向陡坡、阴向陡坡土壤pH值、含水量、毛管孔隙度、非毛管孔隙度随土层深度增加而减少,土壤有机碳(SOC)含量随土层深度增加而降低,且土壤SOC、全氮(TN)、全磷(TP)最小值均出现在阳向缓坡的40～50 cm土层,分别为0.90 g.kg-1、0.08 g.kg-1、0.07 g.kg-1;(2)樟子松人工林土壤C:N、C:P、N:P含量变化范围分别为0.54～22.31、2.06～73.03、0.90～4.86,且立地条件、土层深度对SOC、TN、TP影响交互作用显著;(3)土壤SOC、TN与C:N、C:P、N:P均呈极显著相关,说明樟子松人工林土壤生态化学计量比主要受SOC、TN的调控.
Abstract
In order to clarify the effects of site conditions on the ecological stoichiometry,taking 12-year Pinus syl-vestris var.mongolica plantation with different slope direction,slope degree and slope position in Hunshandake Sandy Land as research object,the soil physical propoties and C,N and P stoichiometric characteristics at a depth of 0-50 cm were measured to sutdy the vertical distribution characteristics of C,N and P and their changing rules in different site conditions.The results showed:(1)The pH value,water content,capillary porosity and non-capillary porosity of flat slope,sunny gentle slope,shady gentle slope,sunny steep slope and shady steep slope decreased with the increase of soil depth.The SOC content decreases with the increase of soil depth.The minimum value of SOC,TN and TP all appeared at the soil layer of 40-50 cm in sunny gentle slope,which was 0.90 g.kg-1,0.08 g.kg-1 and 0.07 g.kg-1,respectively.(2)The variable range of C:N,C:P and N:P of soil in Pinus sylvestris var.mon-golica forest was 0.54-22.31,2.06-73.03 and 0.90-4.86,respectively.The interaction between site conditions and soil depth effected significantly on SOC,TN and TP.(3)There was a significant correlation between soil SOC,TN and C:N,C:P,N:P.The soil ecological stoichiometric ratio of Pinus sylvestris var.mongolica plantation was mainly regulated by SOC and TN.
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