**5. Conclusions**

As far as we know, this is the first study focusing on the effects of land uses intensities on both bacterial communities and biological fertility index in soil cropped in Southern Italy, a typical Mediterranean region. The number of bacterial gene abundances was negatively regulated by soil microbial respiration. As indicated by qPCR and sequencing analyses, different land uses altered bacterial abundance and community structure; in particular, copiotrophic bacterial groups in the grass-covered vineyard decreased, while oligotrophic bacterial taxa increased along with a conservative managing of crop residues and no-tillage. In addition, the determination of SOM and microbial activity parameters allowed deriving relevant conclusions about the effect of land use intensities on the three studied ecosystems. The grass-covered vineyard demonstrated the highest amount of SOM and MBC, while respiration activity, qM, and CUE were higher in the cherry farm. The BFI indicated a higher soil biological fertility in the grass-covered vineyard, which can be reasonably assumed by the preservation of this ecosystem, with none or lower disturbance. These results could be useful to farmers in decisions about the best practices to avoid or reduce the negative impacts of land use intensities. Thus, the BFI could be an effective indicator system in the perceptions and assessment of

soil fertility. More in-depth studies could validate the results of the present research under changing climate conditions and agro-ecosystems and allow the use of the biological fertility index to assess soil quality in agricultural soils.

**Author Contributions:** Conceptualization: M.Y.K. and C.C.; methodology: M.Y.K., P.M., and S.S.; software: M.Y.K.; validation: C.C.; formal analysis: M.Y.K. and C.C.; investigation: M.Y.K., P.M., and S.S.; resources: C.C.; data curation: M.Y.K. and C.C.; writing—original draft preparation: M.Y.K. and C.C.; writing—review and editing: C.C.; visualization: C.C.; supervision: C.C.; project administration: M.Y.K.; funding acquisition: M.Y.K. and C.C.

**Funding:** This research was funded by Global Doc project-CUP H96J17000160002- financed by Regione Puglia, Italy.

**Acknowledgments:** The authors thank Matteo Spagnuolo and Mr. Nicola Carella for scientific and technical assistance, respectively.

**Conflicts of Interest:** The authors declare no conflict of interest.
