摘要
采用氯仿熏蒸浸提法和磷脂脂肪酸法(phospholipid fatty acid,PLFA)研究了我国南亚热带地区新造红椎(Castanopsis hystrix)人工幼龄林土壤微生物生物量与群落结构对模拟氮沉降的响应。施氮量分别为0 kg/(hm2·年)(对照)、50 kg/(hm2·年)(低氮)、100 kg/(hm2·年)(中氮)和150 kg/(hm2·年)(高氮),所施氮素为NH4NO3,试验周期为17个月。结果表明,中氮和高氮处理显著提高了土壤氮素的有效性,但显著降低了土壤p H。所有氮处理均未对土壤有机碳含量产生显著影响,但中氮和高氮处理显著降低了土壤碳氮比,并且显著升高了土壤可浸提有机碳含量。中氮和高氮处理显著降低了土壤微生物生物量碳含量,但显著升高了微生物生物量氮(MBN)含量。再者,中氮和高氮处理显著降低了土壤微生物总PLFAs量、细菌PLFAs量和真菌PLFAs量。3个施氮水平均显著降低了革兰氏阴性菌PLFAs的相对丰度,均显著升高了放线菌PLFAs的相对丰度,但仅高氮处理显著降低了革兰氏阳性菌PLFAs的相对丰度。此外,中、高氮处理均显著升高了真菌细菌PLFAs量比。主成分分析结果表明,3个模拟氮沉降水平均显著影响了红椎人工幼龄林土壤微生物群落结构。冗余分析结果表明,氮沉降下红椎人工幼龄林土壤微生物群落结构的变化与MBN和p H显著相关。以上结果表明,氮沉降显著影响了红椎人工幼龄林土壤微生物群落的稳定性,进而对土壤健康和肥力产生消极影响。
By using fumigation-extraction method and phospholipid fatty acid technique,the effects of simulated nitrogen deposition on soil microbial biomass and community structure in a young Castanopsis hystrix plantation of subtropical China were determined through a field N addition experiment. Nitrogen was added at rate of 0 kg /( hm2·year)( Control),50 kg /( hm2·year)( Low-N),100 kg /( hm2·year)( Medium-N) and 150 kg /( hm2·year)( High-N),respectively for 17 months. The main results were as follows: Medium-N and High-N treatments significantly increased soil N availability,but significantly decreased soil p H in the test plantation. In addition,all the N addition treatments did not significantly influenced the content of SOC,while Medium-N and High-N treatments significantly decreased theratio of soil C / N,but significantly increased the content of soil extractable DOC. Medium-N and High-N treatments significantly decreased the content of MBC,but significantly increased the content of MBN compared with the control plots. Moreover,Medium-N and High-N treatments significantly decreased soil total PLFAs,fungal PLFAs,and bacterial PLFAs. Besides,all the N addition treatments significantly decreased the relative abundance of gram-negative bacterial PLFAs,but significantly increased the relative abundance of actinomycetes PLFAs. However,only High-N treatment significantly decreased the relative abundance of gram-positive bacterial PLFAs. In addition,Medium-N and HighN addition treatments significantly increased the biomass ratio of fungal to bacterial. We also found that N addition significantly affected soil microbial community structure through PCA analysis of 27 individual PLFAs detected in the test soils. Moreover,the redundancy analysis( RDA) demonstrated that the shift of soil microbial community structure under simulated N deposition was significantly correlated to the variations in MBN and soil p H. These results suggest that nitrogen deposition could significantly influence the stability of soil microbial comm
出处
《山东大学学报（理学版）》
CAS
CSCD
北大核心
2016年第5期18-28,共11页
Journal of Shandong University(Natural Science)
基金
国家科技支撑计划资助项目(2012BAD22B01)
关键词
人工幼龄林
模拟氮沉降
土壤微生物生物量
土壤微生物群落结构
南亚热带
Young plantation
simulated nitrogen deposition
soil microbial biomass
soil microbial community structure
south subtropical China
