## 3 Results and Discussion
### Field Test of the Developed Harvester  
Figure 9a,b show the field test of the developed harvester and the stubble after harvesting, and Table 3 shows the performance indexes of the harvester. It was indicated that the harvester only caused 26.9% of stubble damage--this could greatly increase the yield of ratoon season compared to a conventional harvester. The panicle length and stubble height were \(125\pm 80\) mm and \(332\pm 22\) mm, respectively, which verified the availability of the methods developed for double-cutterbar configuration. The feeding quantity and working efficiency reached 5.0 kg\(\cdot\)s\({}^{-1}\) and 0.53 ha\(\cdot\)h\({}^{-1}\). The results indicated that the double-cutterbar structure developed based on rice plant deformation and shearing properties can successfully support the wide header in main crop rice harvesting. This would suggest that this structure can also be applied in regular rice harvesting and other stalk crops.  
\begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline  & **1** & **2** & **3** & **4** & **5** & **6** & **7** & **8** \\ \hline \multirow{4}{*}{**Maximum shearing force/N**} & **0\({}^{a}\)** & \(8.5\pm 5.9\)a & \(14.2\pm 2.8\)a & \(14.0\pm 3.0\)a & \(16.0\pm 4.3\)a & \(19.0\pm 3.5\)a & \(17.3\pm 3.5\)a & \(15.6\pm 3.1\)a & \(14.3\pm 2.4\)a \\  & **15\({}^{b}\)** & \(8.0\pm 2.1\)a & \(12.8\pm 1.5\)a & \(12.9\pm 2.1\)a & \(15.4\pm 4.2\)a & \(17.5\pm 2.6\)a & \(18.0\pm 12.8\)a & \(15.8\pm 1.1\)a & \(16.5\pm 1.3\)a \\  & **30\({}^{b}\)** & \(8.6\pm 3.0\)a & \(12.9\pm 2.9\)a & \(12.5\pm 1.6\)a & \(14.7\pm 3.2\)a & \(17.6\pm 5.4\)a & \(17.0\pm 3.0\)a & \(16.7\pm 2.8\)a & \(16.1\pm 3.6\)a \\ \cline{2-10}  & **9** & **10** & **11** & **12** & **13** & **14** & **15** & \\ \cline{2-10}  & **0\({}^{a}\)** & \(16.6\pm 2.7\)a & \(20.7\pm 1.7\)a & \(23.0\pm 3.1\)a & \(24.0\pm 4.3\)a & \(25.0\pm 11.0\)a & \(24.8\pm 3.3\)a & \(27.0\pm 6.8\)a & \\  & **15\({}^{b}\)** & \(18.4\pm 2.2\)a & \(21.3\pm 4.5\)a & \(22.0\pm 6.2\)a & \(21.8\pm 3.0\)a & \(22.0\pm 6.0\)a & \(24.8\pm 10.7\)a & \(28.0\pm 8.2\)a & \\  & **30\({}^{b}\)** & \(17.6\pm 3.3\)a & \(21.4\pm 3.0\)a & \(23.4\pm 2.4\)a & \(26.0\pm 3.0\)a & \(26.5\pm 12.2\)a & \(27.0\pm 5.1\)a & \(29.5\pm 6.2\)a & \\ \hline \multirow{4}{*}{**Total shearing energy/ml**} & **1** & **2** & **3** & **4** & **5** & **6** & **7** & **8** \\ \cline{2-10}  & **0\({}^{a}\)** & \(12.6\pm 2.8\)a & \(29.7\pm 8.3\)a & \(25.0\pm 8.3\)a & \(35.0\pm 19.1\)a & \(40.0\pm 25.2\)a & \(42.0\pm 22.6\)a & \(46.9\pm 10.7\)a & \(49.4\pm 10.3\)a \\  & **15\({}^{b}\)** & \(18.3\pm 3.2\)a & \(31.1\pm 7.6\)a & \(28.1\pm 7.2\)a & \(36.6\pm 13.2\)a & \(44.5\pm 4.4\)a & \(62.0\pm 54.7\)b & \(62.0\pm 16.2\)b & \(65.5\pm 15.8\)b \\  & **30\({}^{b}\)** & \(19.1\pm 2.4\)a & \(29.3\pm 7.7\)a & \(30.2\pm 6.8\)a & \(39.1\pm 12.3\)a & \(48.4\pm 19.4\)a & \(70.0\pm 15.6\)b & \(72.7\pm 16.8\)b & \(74.9\pm 16.7\)c \\ \cline{2-10}  & **9** & **10** & **11** & **12** & **13** & **14** & **15** & \\ \cline{2-10}  & **0\({}^{a}\)** & \(54.5\pm 9.5\)a & \(58.8\pm 3.7\)a & \(62.2\pm 13.0\)a & \(62.5\pm 19.6\)a & \(70.0\pm 44.8\)a & \(70.5\pm 55.4\)a & \(85.0\pm 19.3\)a & \\  & **15\({}^{b}\)** & \(70.0\pm 27.9\)b & \(70.3\pm 18.1\)b & \(71.2\pm 4.2\)a & \(75.0\pm 29.7\)b & \(80.0\pm 8.2\)b & \(99.8\pm 68.8\)b & \(10.0\pm 45.2\)b & \\  & **30\({}^{b}\)** & \(78.0\pm 21.1\)c & \(80.0\pm 8.4\)a & \(85.0\pm 23.3\)c & \(90.0\pm 19.2\)c & \(109.9\pm 44.1\)c & \(113.8\pm 45.7\)c & \(130.0\pm 57.3\)c & \\ \hline \multicolumn{10}{l}{Values presented are mean \(\pm\) standard deviation from the original data; the replication number of each cutting point is 10; dissimilar lower case group labels (a, b, c) represent a significant difference (\(p<0.05\)) among different cutting angles on the same cutting position.} \\ \end{tabular}
\end{table}
Table 2: Shearing properties on different cutting positions and angles.  
Figure 9: (**a**) Field test of the developed harvesting and (**b**) the stubble after harvesting.