# Irrigation System for a Roller-Type Onion Pot Seeding Machine
## 3 Results and Discussion  
### Results of Flow Rate Test  
The test results of flow rate are summarized in Table 6. For the same experimental conditions, the difference in flow rate between Irrigation Pipe 1 and Irrigation Pipe 2 was less than 5%. Thus, these two irrigation pipes had almost the same flow rate. For the same irrigation hole diameters (Cases 1 and 2, Cases 3 and 4), for the two irrigation pipes, when the hand valve was closed, the flow rate was higher by about 1.63 to 1.71 times, than when the hand valve was open. Also, under the same hand valve conditions (Cases 1 and 3, Cases 2 and 4), for the two irrigation pipes, the flow rate was about 1.38-1.47 times higher for the irrigation hole diameter of 1.5 mm than that for the irrigation hole diameter of 1.0 mm. Thus, the highest flow rate was obtained when the irrigation hole diameter was 1.5 mm, with the hand valve closed (Case 4). The second highest flow rate was obtained when the irrigation hole diameter was 1.0 mm, with the hand valve closed (Case 2).  
Assuming the same flow rate distribution for all irrigation holes, the theoretical water flow rate of each irrigation hole can be derived by dividing the flow rate of irrigation pipe by the irrigation hole number (14), as shown in Table 7.  
The water pressures measured by pressure gauge are shown in Table 8. The water pressure was higher when the hand valve was closed than when it was open. Depending on the irrigation hole diameter, the water pressure was higher for smaller diameter. Thus, the highest water pressure was obtained when the irrigation hole diameter was 1.0 mm and the hand valve was closed (Case 2). The lowest water pressure was obtained when the irrigation hole diameter was 1.5 mm and the hand valve was open (Case 3).  
The test results are outlined in Table 9, and the flow rate error of each irrigation hole was derived by comparing the actual flow rate from Table 9 with the theoretical flow rate from Table 7 (Table 10). The error was the largest in the 13 th irrigation hole of Irrigation pipe 2, with an average error of 9.43%. Depending on the experimental conditions, the average error was the largest in Case 1, because the absolute value of the flow rate is small, which causes a large error with a small change of flow rate.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**ID** & **Irrigation Pipe 1 (ml/s)** & **Irrigation Pipe 2 (ml/s)** & **Error (\%)** \\ \hline Case 1 & 26.67 & 25.4 & 4.76 \\ Case 2 & 43.51 & 41.88 & 3.75 \\ Case 3 & 36.73 & 35.87 & 2.34 \\ Case 4 & 60.61 & 61.42 & 1.34 \\ \hline \hline \end{tabular}
\end{table}
Table 6: Flow rate of each irrigation pipe.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**ID** & **Irrigation Pipe 1 (ml/s)** & **Irrigation Pipe 2 (ml/s)** & **Error (\%)** \\ \hline Case 1 & 1.91 & 1.81 & 3.72 \\ Case 2 & 3.11 & 2.99 & 6.10 \\ Case 3 & 2.62 & 2.56 & 5.18 \\ Case 4 & 4.33 & 4.39 & 8.72 \\ \hline \hline \end{tabular}
\end{table}
Table 7: Theoretical flow rate of each irrigation hole.  
In all the conditions, the average errors were below 10 %. Therefore, it can be considered that a uniform irrigation is obtained regardless of the irrigation hole position.