## 2 Materials and Methods
### Experimental Setup  
The experiment was performed in the premises of Soil and Water Resources Institute (SWRI) of the Hellenic Agricultural Organization \"DEMETER\", in Sindos--Thessaloniki, Greece. The experiment took place between January and March of 2018 and lasted 10 weeks. The experimental procedure included the following intermediate steps:  
Twelve prototype devices were constructed; the devices included a PVC cylinder column of 500 mm diameter (internal diameter 470 mm) and a total height of 50 cm, which subsequently would be filled with the soil and bio-mixture-soil mix in different proportions. Fine meshes were attached to the lower part of the cylinders in order to prevent sediment transport. The cylinders were based on protected metal pans, which were intended to collect leachates from the columns. The columns were roof-protected and not exposed to precipitation or any other external water source. The next step included the sampling of reference agricultural loamy soil from the area of Sindos. The soil was not sieved to simulate realistic agronomic conditions as much as possible. However, any stones or large aggregates were removed. The lower 30 cm of the columns were filled with the control soil (76.5 kg), whilst the upper 20 cm were filled \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Sand (\%) & 58.8 \\ Silt (\%) & 25.6 \\ Clay (\%) & 15.6 \\ pH & 6.70 \\ Electrical Conductivity (\(\upup\)s cm\({}^{-1}\)) & 5460 \\ Organic Matter (\%) & 3.60 \\ Organic Carbon (\%) & 1.30 \\ CaCO\(\up)s (\%) & 1.17 \\ ESP (\%) & 6.13 \\ Cation Exchange Capacity (\(\text{cmol}_{\text{c}}\) kg\({}^{-1}\)) & 32.6 \\ P-Olsen (mg kg\({}^{-1}\)) & 291 \\ Exchangeable Na (mg kg\({}^{-1}\)) & 460 \\ Exchangeable K (mg kg\({}^{-1}\)) & 2550 \\ Exchangeable Ca (mg kg\({}^{-1}\)) & 2965 \\ Exchangeable Mg (mg kg\({}^{-1}\)) & 561 \\ N total (g kg\({}^{-1}\)) & 6.52 \\ NO\({}_{\text{3-N}}\) (mg kg\({}^{-1}\)) & 405 \\ B (mg kg\({}^{-1}\)) & 3.82 \\ Fe (mg kg\({}^{-1}\)) & 39.6 \\ Mn (mg kg\({}^{-1}\)) & 5.54 \\ Zn (mg kg\({}^{-1}\)) & 66.2 \\ Cu (mg kg\({}^{-1}\)) & 2.73 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Main physicochemical characteristics of used bio-mixture. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Value** & **Parameter** & **Value** \\ \hline pH & 8.0 & K (mg L\({}^{-1}\)) & 1.90 \\ EC (\(\upup\)s cm\({}^{-1}\)) & 451 & Na (mg L\({}^{-1}\)) & 7.70 \\ NO\({}_{\text{3}}\) (mg L\({}^{-1}\)) & 1.84 & Ca (mg L\({}^{-1}\)) & 49.1 \\ NO\({}_{\text{2}}\) (mg L\({}^{-1}\)) & 0.00 & Mg (mg L\({}^{-1}\)) & 25.7 \\ NH\({}_{\text{4}}^{+}\) (mg L\({}^{-1}\)) & 0.008 & Zn (mg L\({}^{-1}\)) & 0.08 \\ Cl\({}^{-}\) (mg L\({}^{-1}\)) & 3.98 & B (mg L\({}^{-1}\)) & 0.004 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Main chemical characteristics of irrigation water. with the bio-mixture-soil mix in three different proportions, namely 0% (control, C), 1% (biomix 1%), 2% (biomix 2%) and 3% (biomix 3%) bio-mixture, respectively. Specifically, 46.46 kg of biomix 1% were added to the upper 20 cm of the column for the 1 st proportion, 46.92 kg of biomix 2% were added for the 2 nd proportion and 47.38 kg of biomix 3% were added for the 3 rd proportion. There were 3 columns for the control and three of each treatment, also. The quantities used were such that they could be applied in a realistic agronomic application and were selected intentionally, as they correspond to applications of 27, 54 and 81 tons of bio-mixture per ha. After filling the columns, they remained intact for fifteen days to achieve equilibrium between the soil and the bio-mixture. Regarding irrigation, a period of water application equal to 10 weeks was decided, performing two irrigations every week. Each irrigation dose included 4 L of tap water. The total volume of added water for the whole irrigation period was 80 L per column, which proportionally simulates 4600 mm or 4600 m\({}^{3}\) ha\({}^{-1}\), which is considered to be a common irrigation scheme for cultivations [18; 19; 20].