Responses of Bacterial and Archaeal Communities to Nitrogen Fertilization in a Compost-Amended Soil

The use of organic compost associated with nitrogen (N) fertilization has been intensively studied, revealing the promotion of changes in soil microbial properties. However, few studies have reported the effect of N application in soil amended with organic compost in the long-term on soil microbial communities. This study assessed the responses of bacterial and archaeal communities to N application in soil with a long-term amendment of organic compost obtained from tannery sludge. The application of high and low rates of compost increased the abundance of Actinobacteria and Thaumarchaeota, respectively, while the application of N did not change the relative abundance of bacterial and archaeal groups. The long-term application of compost promoted an increased abundance of specific bacterial groups, including Solirubrobacter, Microvirga, and Geodermatophilus. Regardless of the application of N, higher microbial complexity and interconnection were observed with the application of compost. This study showed a small effect of N fertilization on the microbial community, which suggests that N may not be a limiting factor for microorganisms in soil under long-term amendment of organic compost. Our findings showed that compost application has a stronger impact on soil microbial communities than N fertilization, and it could be useful in agricultural productivity.