Effect of ground mulch managements on soil bacterial community structure and diversity in the non-irrigated apple orchard in Weibei Loess Plateau

Abstract:

Abstract:［Objective］We studied the changes in soil bacterial communities induced by ground mulch managements at different apple growth periods.［Methods］We adopted the denaturing gradient gel electrophoresis (DGGE) with PCRamplified 16S rRNA fragments to determine soil bacterial community structure and diversity.［Results］ Soil bacterial community structure with different ground mulch managements were significantly different． Both the mulch management strategies and apple growth periods affected the predominant groups and their abundance in soil bacterial communities．Grass mulch and cornstalk mulch treatments had higher bacterial diversity and richness than the control at young fruit period and fruit expanding period，whereas film mulch treatment had no significant difference compared with the control．During mature period，bacterial diversity in the control reached its maximum，which may be ascribed to the rapid growth and reproduction of the r-selection bacteria． The clustering and detrended correspondence analysis revealed that differences in soil bacterial communities were closely correlated to apple growth periods and ground mulch managements．Soil samples from the grass mulch and cornstalk mulch treatments clustered together while those mulched with plastic film treatment were similar to the control．The most abundant phylum in soil bacterial community was Proteobacteria followed by Bacteroidetes． Some other phyla were also detected，such as Acidobacteria，Firmicutes，Actinobacteria and Chloroflexi． ［Conclusion］ Mulching with plant (Grass/Cornstalk) had great effects on soil bacterial community structure and enhanced the diversity while film mulch management had no significant effects．

Key words:Keywords: apple orchard，mulching，bacterial community，PCR-DGGE，cloning and sequencing