**Mohammad Yaghoubi Khanghahi \*, Pasqua Murgese, Sabrina Strafella and Carmine Crecchio**

Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, Via Amendola 165/a, 70125 Bari, Italy; patty.murgese@libero.it (P.M.); sabrina.strafella.bio@gmail.com (S.S.); carmine.crecchio@uniba.it (C.C.) **\*** Correspondence: mohammad.yaghoubikhanghahi@uniba.it; Tel.: +39-080-5442854

Received: 24 October 2019; Accepted: 8 November 2019; Published: 10 November 2019

**Abstract:** The current study was performed to investigate the effects of three different long-term land use intensities on adjacent soil plots, namely a winter wheat field, a grass-covered vineyard, and a cherry farm, on soil biochemical, microbial, and molecular parameters. The results showed the maximum content of soil organic matter (SOM) and microbial biomass carbon (MBC) observed in the grass-covered vineyard. Basal respiration (BSR) and the cumulated respiration (CSR) after 25 days of incubation were significantly higher in the grass-covered vineyard and cherry farm, respectively (BSR 11.84 mg CO2–C kg−<sup>1</sup> soil d−1, CSR 226.90 mg CO2–C kg−<sup>1</sup> soil). Grass-covered vineyard showed the highest soil biological fertility index (BFI) score (20) and ranked in the class IV (good) of soil biological fertility. Cereal field and cherry farm had lower BFI scores and the corresponding BFI class was III (medium). In addition, the maximum ribosomal RNA copy number and the highest abundance of oligotrophic bacterial groups (25.52% Actinobacteria, 3.45% Firmicutes, and 1.38% Acidobacteria) were observed in the grass-covered vineyard. In conclusion, the grass-covered vineyard is a more conservative system and could have a large potential to improve total carbon storage in soil, mainly because of the cover crop residue management and the low soil perturbation through the no-tillage system.

**Keywords:** bacterial community structure; biological fertility index; land use; microbial biomass; microbial respiration; ribosomal RNA copy numbers
