河流底泥施用对土壤微生物群落功能多样性和小麦生长的影响

设置0（对照）、20、60和100g·kg-1 3个底泥施用量水平，研究施用底泥对冬小麦籽粒Cd含量以及土壤微生物群落功能多样性的影响。结果表明，60和100g·kg-1底泥施用处理小麦穗质量和千粒重显著高于对照（P〈0．05）。各处理间小麦籽粒cd含量无显著差异。与对照相比，施用底泥并没有显著改变土壤中可培养细菌、真菌和放线菌的数量。整个培养过程中土壤微生物平均颜色变化率（IAWCD）以及96h时微生物多样性指数（Shannon指数、Simpson指数、McIntosh指数）在对照与底泥施用处理间无显著差异。主成分分析（PCA）表明，仅有占总变量方差14．22％的PC3能识别出对照土壤微生物群落碳源利用谱与底泥施用处理间的差异，而PCI（21．76％）、PC2（16．32％）和PC4（11．62％）则无法将对照与底泥施用处理区分开来。可见，该试验条件下合理的底泥施用量并不会对小麦籽粒Cd含量、微生物功能多样性和土壤质量产生显著影响。

Effects of River Sediment Application on Functional Diversity of Soil Microbial Community and Growth of Winter Wheat.

Soil microbial organisms are important components of farmland ecosystems, and soil microbial community structure and activity reflects quality of soil to some extent. A pot experiment was conducted to investigate effects of application of river sediment on population and functional diversity of soil microbe and Cd content of winter wheat grain under four dif- ferent sediment application levels, 0 （control）, 20, 60 and 100 g ~ kg-1. Results show that spike quality and 1 000-grain weight of wheat were much higher （ P 〈 0. 05 ） in Treatments 60 and 100 g . kg -1 than in control and no significant differ- ence was found in grain Cd content between the four river sediment application rates. Compared with control, application of river sediment had no significant influence on populations of bacteria, fungi and actinomyce, and no significant influ- ence on average well color development （IAwcD） , Shannon index （H＇） , Simpson index （D） and McIntosh index （U） of microbe at 96 h, either. Principal component analysis （PCA） demonstrated that only by PC3 which explains 14. 22% of the total variable variance, can the differences between control and the treatments be distinquished in carbon utilization of soil microbial community, while PC1, PC2 and PC4 which explains 21.76%, 16. 32% and 11.62%, respectively, of the total variable variance are useless in this aspect. All of the above imply that in this study river sediment application rate has no significant effects on Cd content of winter wheat grain, functional diversity of soil microbe and soil quality.