Microbial Community Diversities Of Upland Red Soil Under Different Land Use Patterns

Soil microbial community plays a crucial role in ecological sustainability in response to land-use of upland red soil. Ammonia-oxidizing bacteria (AOB) and archaea (AOA) communities under different land use patterns of farmland (F), tea garden (T) and natural forest (G) were investigated. The land use pattern of red soil was a long-term experiment which was set up in 1996 in Taoyuan Agro-ecosystem Research Station (110°72"E,28°52"N). T-RFLP and Clone library methods was conducted to study the diversities of bacteria and AOA/AOB based on amoA genes. The land use patterns showed significant effects on the diversities of AOA and AOB. The diversities of AOA and AOB presented a similar order with farmland=tea garden> natural forest (P<0.05). The variations of soil physical and chemical properties under the land use patterns determined the soil AOA and AOB community structure. Farmland soil possessed the highest nitrification potential followed by tea garden, while natural forest showed the lowest rate. Correlation analysis indicated that the diversity indexes of ammonia-oxidizing bacteria and ammonia-oxidizing archaea were significantly correlated with the potential nitrification rates (PNR), among them ammonia-oxidizing archaea was the most correlated. The BLAST software of Genbank, the nucleotide sequences obtained in this study were checked and analyzed for close relatives and showed that most of the AOA amoA sequences were high related to uncultured Crenarcheota while the remainder belonged to unclassified Archaea. The AOB amoA sequences were most similar to Nitrosospira. These results indicated that land use patterns had significant effected on Ammonia oxidizers which caused the corresponding changes of PNR.