Effects of simulated nitrogen deposition on soil microbial biomass and community structure in a young plantation of Castanopsis hystrix
By using fumigation-extraction method and phospholipid fatty acid technique,the effects of simulated nitro-gen deposition on soil microbial biomass and community structure in a young Castanopsis hystrix plantation of subtropi-cal 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 pH 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 the ratio 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 bacte-rial PLFAs.Besides,all the N addition treatments significantly decreased the relative abundance of gram-negative bacte-rial PLFAs,but significantly increased the relative abundance of actinomycetes PLFAs.However,only High-N treat-ment significantly decreased the relative abundance of gram-positive bacterial PLFAs.In addition,Medium-N and High-N addition treatments significantly increased the biomass ratio of fungal to bacterial.We also found that N addition sig-nificantly 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 un-der simulated N deposition was significantly correlated to the variations in MBN and soil pH.These results suggest that nitrogen deposition could significantly influence the stability of soil microbial community and thus negatively affect soil health and fertility in the young plantation of C.hystrix.
Young plantationsimulated nitrogen depositionsoil microbial biomasssoil microbial community struc-turesouth subtropical China
NETL
NSTL
万方数据
维普
