## 3 Results
### Analysis of Variance  
Different soil management strategies significantly affected both total organic and total extractable carbon (TOC and TEC), and water extractable nitrogen (WEN) concentrations, with higher TOC and TEC content observed in the upper soil layer under more conservative soil management (Table 1). In particular, an average TOC value of 21.87 g kg\({}^{-1}\) was recorded under no-tillage (NT) in comparison to 17.45 g kg\({}^{-1}\) under minimum tillage (MT) management. A greater significant concentration of exchangeable potassium (K\({}^{+}\)) was also observed in untilted soils (Table 1). Under minimum tillage, higher WEN concentrations were observed. Soil management also affected physical properties with a significantly greater bulk density (BD) in untilled soils and, as a consequence, lower air capacity (AC), indicating a tendency to soil compaction (Table 2). Macroporosity (P\({}_{\rm MAC}\)) confirmed this trend, although not significant differences were recorded. Relative field capacity (RFC), that gives an account of the balance between water capacity and air capacity of the soil (in other words, it is an index of the relative importance of meso-micropores to total porosity), was higher in NT than in MT, suggesting major potential risks of anaerobic conditions due to reduced presence of air in the soil porosity. \begin{table}
\begin{tabular}{l c c c c c c c c c c c c c} \hline \hline
**Source of** & **WROC** & **WEN** & **C\({}_{\rm lim}\)** & **TOC** & **TTC** & **HA\({}_{-}\)FA** & **N** & **P\({}_{\rm O}\)** & **CC\({}^{2+}\)** & **K\({}^{+}\)** & **Mg\({}^{2+}\)** & **Na\({}^{+}\)** \\
**Variation** & **mg-kg\({}^{-1}\)** & **mg-kg\({}^{-1}\)** & **mg-kg\({}^{-1}\)** & **g-kg\({}^{-1}\)** & **g-kg\({}^{-1}\)** & **g-kg\({}^{-1}\)** & **g-kg\({}^{-1}\)** & **g-kg\({}^{-1}\)** & **mg-kg\({}^{-1}\)** & **mg-kg\({}^{-1}\)** & **mg-kg\({}^{-1}\)** & **mg-kg\({}^{-1}\)** \\ \hline Soil & & & & & & & & & & & & & & \\ management & 49.351 & 25.186 & 491.03 & 19.66 & 12.008 & 6.792 & 1.470 & 54.055 & 8.10 & 0.139 & 6682.9 & 1043.89 & 25.584 & 29.122 \\ (mean) & 0.1720 & 0.2073 & 0.8641 & 0.0325* & 0.0415* & 0.3200 & 0.4441 & 0.6690 & 0.1674 & 0.6251 & 0.9688 & 0.0233* & 0.1663 & 0.1852 \\ \hline No-slip & & & & & & & & & & & & & \\ Minimum & 20.244 & 10.111 & 50.88 & 21.57* & 13.63* & 6.23 & 1.52 & 60.72 & 8.07 & 0.14 & 6480.3 & 112011.8* & 211.65 & 27.87 \\ sliper (MT) & 20.236 & 40.24* & 67.23 & 17.45 b & 10.54b & 7.34 & 1.42 & 47.37 & 8.14 & 0.13 & 6681.6 & 967.0b & 220.03 & 30.37 \\ \hline \end{tabular}
* and ** indicate respectively differences at P \(\leq\) 0.05 and P \(\leq\) 0.01. Means followed by different letters are significantly different according to the SNK test (P = 0.05). P(? F) indicates the probability value (\(p\)-value) to determine whether to reject the null hypothesis. WEOC = water extractable organic carbon; WEN = water extractable nitrogen; C\({}_{\rm lim}\)omass = microbial biomass carbon; TOC = total organic carbon; TEC = alkali-extractable carbon; HA\({}_{-}\)FA = humic and fulvic acid carbon; N = total nitrogen; P\({}_{-}\)Olsen = Olsen available phosphorus; EC = electrical conductivity; Ca\({}^{2+}\), Mg\({}^{2+}\), Na\({}^{+}\), K\({}^{+}\) = exchangeable cations. (\(n=24\)).  
\end{table} 
Table 1: Results of nested analysis of variance carried out on soil chemical and biological parameters. According to [PERSON] et al. [14], optimal and intermediate values were observed under MT for bulk density (0.9-1.2 g cm\({}^{-3}\), optimal range), air capacity (0.10-0.14 cm\({}^{3}\), intermediate range) and macroporosity (0.04-0.07 cm\({}^{3}\) cm\({}^{-3}\), intermediate range) and values slightly over than the optimal threshold for RFC (0.6-0.7, optimal range). Except for BD, values recorded under NT were all indicative of limited aeration conditions.