Soil Nitrogen Mineralization And Microbial Community Characteristics In Different Age Of Tea Plantation

Management practice such as pruning and fertilization changed the soil nutrient status,which consequently alter the soil microbial community of tea plantation.In order to investigate the effect of tea plantation ages on soil nitrogen mineralization and microbial community,soil samples were collected from tea plantation with two soil depths at 20,25,38 and 48 year of tea plantation ages.Controlled laboratoryincubation experiment was used to determine the nitrogen mineralization rate.The soil bacterial and fungal communities were analyzed by T-RFLP and real-time PCR to explore the role of soil bacteria and fungi in soil nitrogen mineralization.The main results are as follows:(1)Tea plantation significantly changed soil physicochemical properties,where soil pH decreased and the nutrient content increased depending on plantation ages.The soil organic carbon,available nitrogen and available phosphorus content increased during 38 years of age and then decreased.The net nitrification rate of tea plantation was significantly higher than that of T0,the net nitrification rate and net nitrogen mineralization rate increased during 38 years of age and then decreased in 0?20cm soil.Soil ?-glucosidase,urease and invertase play an important role in soil ammonification.(2)Bacterial communities are more sensitive to tea plantation age than fungal communities.Tea plantation significantly changed the structure of soil bacterial and fungal community,the bacterial community structure showing significant differences among different plantation ages but the fungal community structure was not significantly different.The bacterial diversity index showed a downward trend with the increase of tea plantation age,while the fungal diversity index had no significant difference.The abundance of bacterial and fungal communities were higher within a certain period of time,afterwards decreased with the increasing of tea plantation age.(3)Soil available nitrogen and phosphorus are the key factors affecting soil bacterial community structure while organic carbon content is the main factor to alter soil fungal community structure depending on tea plantation age.Fungi play an important role in soil nitrogen mineralization,and their contribution to soil net nitrification and net nitrogen mineralization is greater than that of bacteria.