黄土丘陵区植被次生演替灌木种群的土壤养分效应

Effect of shrub species during vegetation secondary succession on soil nutrient on the hilly-gullied loess region

【目的】研究黄土丘陵区植被次生演替灌木群落形成过程中土壤养分的变化情况。【方法】以白羊草群落为对照,选取杠柳、狼牙刺、丁香、虎榛子和柠条5种乡土树种为研究对象,测定其土壤养分含量,计算灌木群落形成变化过程中的土壤养分指数(Soil Nutrient Index,SNI),分析了各养分因子间的线性相关关系。【结果】不同灌木初期对土壤养分的适应能力大小顺序为:柠条(0.072)>狼牙刺(0.114)>杠柳(0.163)>丁香(0.172)>虎榛子(0.292)。不同植被物种群落土壤SNI值大小顺序为:虎榛子群落(0.979)>狼牙刺群落(0.535)>柠条群落(0.457)>丁香群落(0.341)>杠柳群落(0.333)>白羊草群落(0.145)。从不同灌木群落形成过程所产生的土壤养分改善效应来看,各参试群落相对于白羊草群落土壤养分的增幅分别为:虎榛子(4.740倍)、狼牙刺(2.909倍)、柠条(2.661倍)、杠柳(1.169倍)和丁香(1.168倍)。各土壤养分因子间除土壤全磷与有效磷和有效钾的相关性不显著外,其余各土壤养分因子间均表现出极显著的线性相关关系(P<0.01)。【结论】不同灌木种群所需的适宜土壤养分条件和对土壤养分的改善效应存在较大差异;植被次生演替灌丛阶段的土壤养分明显优于草本阶段,植被次生演替过程土壤养分呈逐步改善的趋势。

[Objective] This paper studied the change of soil nutrients during the process of shrub community forming vegetation secondary succession on the hilly-gullied loess region. [Method] The soil nutrient is detected in five shrub trees, namely Periploca sepium, Sophora davidii, Syringa pekinensis, Ostryopsis davidiana, Caragana intermedia and comparative Bothriochloa ischaemum community. We have evaluated comprehensively on soil nutrient index during the process of shrub community form and analyzed the linear correlation of soil nutrient factors. [Result] The results indicated that different shrub trees in early stage has different adaptability of soil nutrient in the order of C. intermedia （0. 072）〉 S. davidii （0. 114）〉P, sepium （0. 163）〉S. pekinensis （0. 172）〉O. davidiana （0. 292）. Soil nutrient index of different shrub community in the order of O. davidiana （0. 979）〉S. davidii （0. 535）〉C. interrnedia （0. 457）〉 S. pekinensis （0. 341）〉P. sepium （0. 333）〉B. ischaemum（0. 145）. In term of effect of different shrub tree the process of its community form on soil nutrient improved,its related to soil nutrient increasing amplitude of B. ischaernurn community separately were O. davidiana （4. 740 times）,S, davidii （2. 909 times）, C. interrnedia （2. 661 times）,P, sepiurn （1. 169 times）,S, pekinensis（1. 168 times）. Correlation analysis showed that soil nutrient factors were significantly correlated each other（P〈0.01） ,but didn＇t show significant correlation with total P and available P,as well as available K. Different shrub tree were differente in proper soil nutrients of plant ecesis and improvement of soil nutrients. [Conclusion]Shrub community was better than herb community in soil nutrient. The process of vegetation secondary succession has an improved trend of soil nutrient.