莠去津对野生植物群落下土壤微生物功能多样性的影响

为探明亚致死剂量农药对土壤微生物多样性影响，基于大田控制试验，采用Biolog-ECO微平板技术分析喷施亚致死剂量的莠去津对野生植物群落下土壤微生物群落功能多样性的影响.结果表明:① 莠去津的喷施浓度对土壤微生物群落利用全部碳源的能力无显著影响（P>0.05），但与喷施处理后第30天相比，处理后第60天的土壤微生物群落利用全部碳源的能力有所降低，其中处理Ⅰ〔喷施浓度（以质量浓度计）为1 200 g/hm2〕、处理Ⅲ（喷施浓度为300 g/hm2）显著下降（P < 0.05），而CK（对照组）、处理Ⅱ（喷施浓度为600 g/hm2）降低程度不显著（P>0.05），并且其各处理间土壤微生物群落对全部碳源的利用能力大小为CK >处理Ⅲ >处理Ⅱ >处理Ⅰ.② 喷施处理后第30天土壤微生物群落对碳水化合物类碳源的利用能力最强，对羧酸类碳源的利用能力相对较弱；喷施处理后第60天土壤微生物群落对碳水化合物类碳源的利用能力降幅最大，处理Ⅰ、处理Ⅱ、处理Ⅲ分别下降了0.63、0.78、0.85、0.76.③ 喷施除草剂后第30天处理Ⅱ的Shannon-Wiener指数和Simpson指数显著低于其他处理（P < 0.05），而第60天各处理间多样性指数无显著差异；与喷施处理后第30天相比，第60天各处理多样性指数都有所下降，但没有显著差异（P>0.05）.④ 对土壤微生物群落碳源利用能力进行主成分分析结果显示，提取的与土壤微生物碳源利用相关的主成分累积贡献率为86.6%，主成分1能够区分喷施处理后两个时期的土壤微生物群落特征.⑤ 冗余分析（RDA）表明，pH是土壤微生物利用碳源能力差异的重要影响因素之一.研究显示，除草剂莠去津的施用可在一定程度上降低野生植物群落下土壤微生物群落功能多样性. 

Effects of Atrazine on Soil Microbial Functional Diversity of Wild Weed Communities

Abstract: To evaluate the impacts of atrazine on soil microbial communities under wild weed communities, the functional diversity of soil microbial communities in different treatments was investigated with Biolog-ECO micro-plates. The results showed that spraying concentrations of atrazine had no significant influence on soil microbial carbon utilization (P>0.05). Compared with the 30^th day after spraying, the soil microbial carbon utilization ability was reduced in the 60^th day. The I and III treatments were reduced significantly (P<0.05), while the CK and II treatments had no significant reduction (P>0.05). After spraying herbicide, the order of the ability of soil microbial carbon utilization after 60 days was CK>III>II>I. The utilization abilities of different types of carbon sources were different after spraying herbicide. 30 days after spraying, the soil microbial communities mostly used carbohydrates as carbon source, and used Carboxylic acid least. 60 days after spraying, the ability to use carbohydrates as carbon source was largely declined, with treatments declined by 0.63,0.78,0.85,0.76 respectively. 30 days after spraying herbicide, the Shannon-Wiener and Simpson indices of soil microbial community in treatment II were significant less than other treatments (P<0.05), but the diversity indices showed no significant differences among treatments 30 days after spraying herbicide. Compared with the 30^th day after spraying, the diversity index was decreased in the 60^th day after spraying, but the differences were not significant (P>0.05). Principal component analysis demonstrated that the principal components extracted from 31 carbon sources were related to soil microbial carbon source utilization; the principal components accounted for 86.6% of the total variables variance. Principal component 1 could separate characteristics of soil microbial community after spraying. Redundancy Analysis showed that pH was the main factor that was most highly correlated with variance of soil microbial carbon utilization. The functional diversity of soil microbial communities will be changed by spraying the herbicide atrazine.