*3.1. Chemical and Microbial Parameters*

Results of the soil chemical parameters and microbial activity in different land use are summarized in Table 3. There was no difference among the three land uses in terms of soil pH and texture. However, cherry farm soil had a slightly lower sand and silt content and higher pH than the other soils. The results showed that soil organic carbon (SOC) of the samples from grass-covered vineyard and from cereal field was significantly greater than that from the cherry farm. In particular, SOC was 1.82% and 1.69% in the grass-covered vineyard and cereal field, respectively, which was 1.33 and 1.24 times more than that in the cherry field (Table 3). Accordingly, the maximum soil organic matter (SOM) was recorded in grass-covered vineyard, while the lowest was found in cherry farm (3.13% and 2.35%, respectively). The maximum values of microbial biomass (MBC) was observed in the grass-covered vineyard soil (201.92 μgCg−<sup>1</sup> soil), which was about 2.45% and 8.29% more than that in cereal and cherry farm soils, respectively. Basal soil respiration (BSR) and the cumulated respiration (CSR) after 25 days of incubation were significantly higher in grass-covered vineyard and cherry farm, respectively (BSR 11.84 mg CO2–C kg<sup>−</sup><sup>1</sup> soil d<sup>−</sup>1, CSR 226.90 mg CO2–C kg−<sup>1</sup> soil) than in the cereal field (BSR 9.73 mg CO2–C kg<sup>−</sup><sup>1</sup> soil d<sup>−</sup>1, CSR 153.91 mg CO2–C kg−<sup>1</sup> soil). The highest and significantly different value of efficiency of microbes to decompose organic matter (CUE) was found in cherry farm (138.08 μg C g−<sup>1</sup> soil). The highest amount of metabolic quotient (qCO2) were detected in grass-covered vineyard (0.058 mg CO2–C 10<sup>−</sup><sup>2</sup> h−<sup>1</sup> mg MBC<sup>−</sup>1) and cherry farm (0.056 mg CO2–C 10−<sup>2</sup> h−<sup>1</sup> mg MBC<sup>−</sup>1), which were about 16% and 12% higher than that in the cereal field. We also found statistically significant

differences among land uses in term of carbon mineralization quotient (qM). These values varied from 0.91% in the cereal field to 1.66% in the cherry farm.


**Table 3.** Chemical and microbial parameters under different land use.

Means (± standard error) of each parameter followed by a similar letter are not significantly different based on the least significant difference (LSD) test at the 5% probability level. SOC: total organic carbon, SOM: total organic matter, MBC: microbial biomass C, CUE: microbial carbon use efficiency, BSR: basal soil respiration, CSR: cumulative soil respiration, qCO2: metabolic quotient, qM: mineralization quotient, 16S rRNA- CN: Bacterial 16S rRNA gene copy numbers.

Regression of cubic equation models significantly fitted (*P* < 0.01) correlations between microbial respiration rate and time period of incubation. The coefficients of determination (R2) of the equations were 0.98, 0.95, and 0.99 in the cereal field, grass-covered vineyard, and cherry farm, respectively (Table 4, Figure 2).

**Table 4.** Regression coefficient for determining the relationship between the microbial respiration rates in different land use after an incubation period of 25 days.


\*\* corresponds to significance at *p* < 0.01.

**Figure 2.** Respiration rate during 25 days of incubation in cereal field (-), grass-covered vineyard (), and cherry farm (-).
