水分生态环境对刺槐细根垂直分布的影响

采用土钻法，对安塞县和长武县的刺槐细根面积垂直分布特征进行调查研究，结果表明:（1）刺槐细根的垂直分布与水分生态环境密切相关，现存的细根密度是对具体生境逐步适应调整的结果。（2）刺槐在遗传特性上表现为深根性树种。刺槐细根的垂直分布除了受树种遗传特性的影响，很大程度上受水分生态环境的影响。（3）刺槐细根的垂直分布区域与降雨的补偿深度基本一致，如果土壤中的水分得不到很好的补偿，将对刺槐的生长造成很大影响。因此，黄土高原营造人工林，应充分考虑降水对土壤含水量的补偿深度和补偿程度，以水分生态环境中所能容纳的适宜细根密度为依据确定造林密度，才能使树木达到最大生产力。

Effect of Soil Water Environment on Vertical Fine Root Distribution of Robinia pseudoacacia

Method of soil auger was used to research vertical fine root distribution of Robinia Pseudoacacia under different climates(Ansai county and Changwu county).The results showed as follows:(1)Vertical fine root density distribution of Robinia Pseudoacacia is influenced by soil water condition.The fine root density of Robinia Pseudoacacia is decided by the habitat where they live.(2)Robinia Pseudoacacia is a deep root tree.The characteristic of vertical fine root density distribution of Robinia Pseudoacacia is not only influenced by the heredity characteristic,but also influenced by the soil water condition.(3)The area of vertical fine root distribution of Robinia Pseudoacacia is consistent with the area where the soil water can retrieve from rainfall.If the soil water can not retrieved well from rainfall,the tree will not grow well.So on the Loess Plateau,the extent and degree of soil water retrieving from rainfall should be taken into account when planting trees.The density of tree should be decided by the fine root density that is fit to the soil moisture environment in order to exert the best productivity of tree.