## 5 Results
### Temporal Single Regression Analysis  
A first analysis was applied on bare soils having different \(h^{\prime}\). Single regressions among \(\sigma^{\circ}\) vs. \(m_{\rm v}\) and \(h^{\prime}\) were calculated separately for two plots (IDs 460 and 222) that remained bare until the first week of May; \(h^{\prime}\) values ranged between 0.93-1.77 and 1.42-2.05 cm, for plots 460 and 222 respectively (Table 3). Correlations, \(r\), are classified according to [PERSON], 1996 [57]; slopes, \(m\), and intercepts, \(q\), values could be employed to apply empirical or semi-empirical models (e.g., the WC model [17]). No significant correlations characterized the \(\sigma^{\circ}\) vs. \(h^{\prime}\) regressions (not shown). Noticeable, very strong and significant \(\sigma^{\circ}\) vs. \(m_{\rm v}\) correlations were found for XVV (plot 460), CHH and for L frequencies (plot 222); while, strong (i.e., 0.6 \(<\)\(r\) \(<\) 0.8) correlations were not significant (\(p\)-value \(>\) 0.1). For plot 460 two _quasi_-significant correlations were found at XHH and LVV, respectively. The highest \(\sigma^{\circ}\) vs. \(m_{\rm v}\) correlations were found at L frequency (\(\approx\)0.99). A second analysis was applied on vegetated plots (Table 4). Noticeable, \(\sigma^{\circ}\) vs. \(h^{\prime}\) returned no significant correlations (not shown). Regarding \(\sigma^{\circ}\) vs. \(m_{\rm v}\), only moderate to strong correlations (0.4 \(<\)\(r\) \(<\) 0.8) were found as the capability of the signal of perceiving the \(m_{\rm v}\) is attenuated by the  
Figure 7: SVV (\(m_{\rm v}\) and \(F_{\rm v}\)) and \(\sigma^{\circ}\) temporal dynamics for the plot 450 (barley); co-polarized \(\sigma^{\circ}\) are shown in the upper left panel, whereas cross-polarized \(\sigma^{\circ}\) are in the upper right panel. Vertical blue bars mark \(m_{\rm v}\) peaks separating three consecutive drying periods. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \(\sigma^{\circ}\) vs. \(m_{\rm v}\) & \(r\) & \(m\) & \(q\) & \(p\)-Value & \(\sigma^{\circ}\) vs. \(m_{\rm v}\) & \(r\) & \(m\) & \(q\) & \(p\)-Value \\ \hline \(\mathbf{X_{HH}}\) & 0.79 & 1.00 & \(-\)30.12 & 6.0 \(\times\) 10\({}^{-2}\) & \(\mathbf{X_{HH}}\) & 0.62 & 0.46 & \(-\)22.89 & 2.6 \(\times\) 10\({}^{-1}\) \\ \(\mathbf{X_{VV}}\) & 0.83 & 1.01 & **29.98** & **4.0 \(\times\) 10\({}^{-2}\)** & \(\mathbf{X_{VV}}\) & 0.61 & 0.43 & \(-\)22.40 & 2.8 \(\times\) 10\({}^{-1}\) \\ \(\mathbf{C_{HH}}\) & 0.60 & 0.59 & \(-\)24.29 & 2.1 \(\times\) 10\({}^{-1}\) & \(\mathbf{C_{HH}}\) & 0.83 & **0.56** & \(-\)**25.79** & **8.0 \(\times\) 10\({}^{-2}\)** \\ \(\mathbf{C_{HV}}\) & 0.63 & 0.94 & \(-\)41.30 & 1.8 \(\times\) 10\({}^{-1}\) & \(\mathbf{C_{HV}}\) & 0.71 & 0.54 & \(-\)34.42 & 1.8 \(\times\) 10\({}^{-1}\) \\ \(\mathbf{C_{VV}}\) & 0.71 & 0.91 & \(-\)29.61 & 1.2 \(\times\) 10\({}^{-1}\) & \(\mathbf{C_{VV}}\) & 0.77 & 0.52 & \(-\)24.14 & 1.3 \(\times\) 10\({}^{-1}\) \\ \(\mathbf{L_{HH}}\) & 0.46 & 0.67 & \(-\)37.84 & 3.6 \(\times\) 10\({}^{-1}\) & \(\mathbf{L_{HH}}\) & **0.99** & **1.12** & \(-\)**51.45** & **6.2 \(\times\) 10\({}^{-4}\)** \\ \(\mathbf{L_{HV}}\) & 0.65 & 0.78 & \(-\)48.88 & 1.6 \(\times\) 10\({}^{-1}\) & \(\mathbf{L_{HV}}\) & **0.99** & **0.98** & \(-\)**54.99** & **2.8 \(\times\) 10\({}^{-4}\)** \\ \(\mathbf{L_{VV}}\) & 0.74 & 1.20 & \(-\)46.16 & 9.6 \(\times\) 10\({}^{-2}\) & \(\mathbf{L_{VV}}\) & **0.99** & **1.34** & \(-\)**56.59** & **4.2 \(\times\) 10\({}^{-4}\)** \\ \hline \end{tabular}
\end{table} 
Table 3: \(\sigma^{\circ}\) vs. \(m_{\rm v}\) over bare soil for plot 460 (left panel) and plot 222 (right panel). Significant and very strong correlations (i.e., \(p\)-value less than 0.05 and \(r\) \(>\) 0.8) are highlighted in dark-grey with values in bold: _quasi_-significant correlations (i.e., 0.05 \(<\)\(p\)-value \(<\) 0.1) are underlined. vegetation cover. Most significant \(\sigma^{\circ}\) vs. \(m_{\rm v}\) correlations were found at L frequency, highlighting that the longer the wave the better the canopy penetration.