晋西黄土区林草复合系统刺槐根系分布特征

Distribution characteristics of Robinia pseudoacacia roots in silvopastoral system in the Loess region of west Shanxi

为了研究晋西黄土区林草复合系统树木根系分布特征,采用钻土芯法对刺槐×天然草复合系统0-100 cm土层中刺槐根系生物量、根长和根表面积进行了测定和分析。研究结果表明:同一坡向上刺槐根系生物量、根长和根表面积分布具有相似的特征,在垂直方向上,根系生物量、根长和根表面积均随土层深度的增加呈指数减少,且集中在0～60 cm的土层中;在水平方向上,离树行越近,刺槐根系生物量、根长和根表面积均越大。不同坡向刺槐根系差异显著,相同径级、相同位置阳坡刺槐根系生物量、根长和根表面积均小于阴坡,但根系消弱系数表明阳坡刺槐细根深层土壤生物量分布比例较阴坡多。

The objective of this study was to investigate distribution characteristics of Robinia pseudoacacia roots in silvopastoral system in the Loess Plateau of west Shanxi. Roots biomass, length and surface area of Robinia pseudoacacia in 0 - 100cm soil profile in silvopastoral system were measured and analyzed by using auger meth- od. The results of this paper showed as follows ： Distribution characteristics of biomass, length and surface area of Robinia pseudoacacia roots in silvopastoral system were similar in the same slope. Vertically, the roots declined exponentially with increased depth of soil and concentrated at the 0 - 60cm soil zone ; Horizontally, the roots in. creased with the decrease distance from the tree row. There were obvious differences of Robinia pseudoacacia roots distribution among different slopes. The biomass, length and surface area of Robinia pseudoacacia roots were lower on southern slope than on northern slope in the same condition, but the value of root extinction coeffi- cient showed that the distribution proportion of fine root biomass in deeper soil was higher on southern slope than on northern slope.