延安燕沟流域刺槐根系分布特征

摘要

Root distribution characters represent special ecological significance, as they indicate the adaptability and improvement of trees to the environment. Soil drilling method was adopted to investigate the root distribution characters of Robinia pseudoacacia in northern hillside of Yangou watershed. The results indicated that.① fine roots were concentrated in the soil layer of 0 -60 cm , coarse root density distribution appeared in "high - low- high" three-density areas, and 80-100 cm soil was the low-density area; ②the horizontal distribution of fine and coarse root biomass can be described by "parabola"; ③ with the increase of the distance away from the trunk, the value of root extinction coefficientβ for fine roots gradually increased, the maximum value ofβ was 0. 994 in the 150 cm and for the coarse root was 0. 992 in the 100 cm; ④ within the horizontal range of 0-150 cm, the fine root extinction coefficientβ(0. 992) was greater than the coarse root (0. 990), showing that the depth distribution of fine root was greater than coarse roots, which expanded the space of absorption and utilization for locust on moisture and nutrients.%根系分布特征有着特殊的生态意义,它反映出林木适应和改善环境的功能.采用土钻法对延安燕沟流域阴坡刺槐根系分布特征进行调查和研究.结果表明,①细根集中分布在表层0～60 cm土层,粗根根系密度分布呈"高-低-高"3个密度区,且80～100 cm土层为低密度区;②细根和粗根生物量水平分布均可用"抛物线"描述;③随着距树干距离的增加,细根根系消弱系数β值逐渐增大,150 cm处β值达到最大,为0.994,而粗根根系消弱系数卢在100 cm处达到最大,为0.992;④水平方向0～150 cm范围内,细根根系消弱系数β值(0.992)大于粗根根系消弱系数β值(0.990),说明细根的分布深度大于粗根,这种分布特征扩大了刺槐对水分养分的吸收利用空间.