# Irrigation System for a Roller-Type Onion Pot Seeding Machine
## 3 Results and Discussion
### Irrigation Amount of Pot Tray  
The irrigation amount of each pot tray cell can be determined using the flow rate of each irrigation hole, translational speed of pot tray, and irrigation length of the pot tray cell (Equation (1)) [12]. The shape of the pot tray cell is a truncated cone with its top diameter being larger than the bottom diameter [6]. Therefore, the top diameter of the pot tray cell is considered for the irrigation length. The sum of theoretical flow rates of irrigation pipes 1 and 2 (Table 7) was taken as the flow rate per irrigation hole. In the roller-type pot-seeding machine used in this study, the translational speed of the pot tray is 74.93 mm/s and the top diameter of the pot tray cell is 16 mm [6]. The calculated irrigation amounts per pot tray cell are given in Table 11. The irrigation amount per pot tray cell is in the range of 0.79-1.86 ml. The largest irrigation amount is obtained when the irrigation hole diameter is 1.5 mm and the hand valve is closed (Case 4). The smallest irrigation amount is obtained when the irrigation hole diameter is 1.0 mm and the hand valve is open (Case 1).  
\[Q_{cell}=\frac{q\times d_{cell}}{v_{pot}} \tag{1}\]  
where  
\(Q_{cell}=\) irrigation amount per pot tray cell, ml  
q = flow rate per irrigation hole, ml/s  
\(v_{pot}=\) translational speed of the pot tray, mm/s  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{3}{*}{**ID**} & \multicolumn{4}{c}{**Irrigation Pipe 1 (ml/s)**} & \multicolumn{4}{c}{**Irrigation Pipe 2 (ml/s)**} \\ \cline{2-9}  & \multicolumn{4}{c}{**Hole Number**} & \multicolumn{4}{c}{**Hole Number**} \\ \cline{2-9}  & **1** & **6** & **9** & **13** & **1** & **6** & **9** & **13** \\ \hline Case 1 & 2.09 & 9.95 & 3.66 & 4.19 & 10.50 & 1.66 & 8.29 & 10.50 \\ Case 2 & 5.79 & 3.22 & 0.64 & 5.79 & 7.36 & 2.68 & 3.34 & 12.04 \\ Case 3 & 1.91 & 8.02 & 4.58 & 1.15 & 0 & 3.52 & 10.16 & 7.42 \\ Case 4 & 1.39 & 1.15 & 6.00 & 3.23 & 6.83 & 8.20 & 7.74 & 7.74 \\ Average & 2.79 & 5.58 & 3.72 & 3.59 & 6.17 & 4.01 & 7.38 & 9.43 \\ \hline \hline \end{tabular}
\end{table}
Table 10: Flow rate error of each irrigation hole.  
\begin{table}
\begin{tabular}{c c} \hline \hline \multicolumn{1}{c}{**ID**} & \multicolumn{2}{c}{**Water pressure (Bar)**} \\ \hline Case 1 & 0.02 \\ Case 2 & 0.03 \\ Case 3 & 0.01 \\ Case 4 & 0.02 \\ \hline \hline \end{tabular}
\end{table}
Table 8: Water pressures according to experimental conditions.  
\begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{3}{*}{**ID**} & \multicolumn{2}{c}{**Irrigation Pipe 1 (ml/s)**} & \multicolumn{2}{c}{**Irrigation Pipe 2 (ml/s)**} \\ \cline{2-5}  & **1** & **6** & **9** & **13** \\ \hline Case 1 & 1.87 & 2.10 & 1.98 & 1.99 & 1.62 & 1.78 & 1.66 & 2.00 \\ Case 2 & 2.93 & 3.01 & 3.13 & 2.93 & 2.77 & 2.91 & 3.09 & 3.35 \\ Case 3 & 2.67 & 2.41 & 2.50 & 2.65 & 2.56 & 2.65 & 2.30 & 2.75 \\ Case 4 & 4.27 & 4.28 & 4.07 & 4.47 & 4.69 & 4.75 & 4.05 & 4.73 \\\(d_{cell}\) = top diameter of the pot tray cell, mm  
Furthermore, the total amount on the entire pot tray, when it passes through the ambit of water sprayed from the irrigation pipes can be determined by Equation (2) using the total length of pot tray. The total length of pot tray used in the roller-type pot-seeding machine is 619 mm [6]. The calculation results are listed in Table 12. The total irrigation amount of the pot tray is in the range of 30.73-72.04 ml. The largest irrigation amount is obtained when the irrigation hole diameter is 1.5 mm and the hand valve is closed (Case 4). The second irrigation largest amount is obtained when the irrigation hole diameter is 1.0 mm and the hand valve is closed (Case 2).  
\[Q_{pot}=\frac{q\times l_{pot}}{v_{pot}} \tag{2}\]  
where  
\(Q_{pot}\) = irrigation amount of the entire pot tray, ml  
\(l_{pot}\) = total length of pot tray, mm