侧柏、山毛桃单栽及侧柏-山毛桃混栽幼苗根际土壤环境特征

侧柏（Platycladus orientalis）和山毛桃（Prunus davidiana）均属太行山地区植被恢复的先锋树种。以侧柏和山毛桃幼苗为研究对象，利用盆栽试验比较不同种植模式（侧柏单栽、山毛桃单栽和侧柏-山毛桃混栽）对根际土壤养分状况和微生物数量特征的影响。结果表明，山毛桃单栽和侧柏-山毛桃混栽显著降低了根际土壤pH（p<0.05），提高了土壤养分的有效性。相对单栽，混栽种植显著提高了根际土壤有机质、全氮和速效钾的含量（p<0.05）。单栽及混栽种植均在一定程度上提高了根际区土壤速效磷含量，但并未造成显著性差异（p>0.05）。通过分析根际微生物数量发现，侧柏-山毛桃混栽显著提高了根际土壤细菌和放线菌的数量，显著降低了根际土壤真菌的数量（p<0.05），而山毛桃单栽则显著提高了根际土壤放线菌和真菌的数量（p<0.05）。综合分析表明混栽幼苗能有效改善根际土壤养分状况和微生物活性，因而，侧柏纯林引种山毛桃可作为防止土壤退化的一种有效措施。

Rhizospheric Soil Environmental Characteristics under Pure and Mixed Plantations of Platycladus orientalis and Prunus davidiana Seedlings

Platycladus orientatil and Prunus davidiana are two dominant tree species in Taihang mountainous area.A pot experiment was adopted to compare the effects of planting patterns (pure and mixed) on rhizospheric soil available nutrients,as well as soil microorganism populations.The results showed that the pure planting of P.davidiana and mixed planting of two species significantly decreased rhizospheric soil pH (p<0.05).Relative to the pure planting,the mixed planting significantly increased rhizospheric soil organic matter,TN and rapidly available potassium contents (p<0.05).Pure and mixed planting patterns all tended to increase soil available phosphorus content,while the difference was not significant (p>0.05).Furthermore,from the analysis of rhizospheric soil microbial population,we found that mixed planting could significantly increase rhizospheric soil bacteria and actinomyces populations while decrease fungus amount (p<0.05).In addition,pure planting of P.davidiana had significantly increased the population of actinomyces and fungi in rhizosphere soil (p<0.05).Comprehensively,the mixed planting pattern could effectively improve rhizospheric soil available nutrient status and soil microbial activity;therefore,to introduce P.davidiana to pure P.orientatil plantation was suggested as a practicable way to prevent soil degradation.