## 3 Results
### Validation Test Results  
In order to verify the fertilizer discharge effect of the optimized spiral-pushing fertilizer applicator (OSPFA), based on the optimal results of optimization, it was determined that the accumulation fertilizer section pitch of the spiral-pushing fertilizer applicator was 38 mm, with the diameter of 42 mm, and the fertilizer discharge section was 20 mm, with a diameter of 40 mm. The urea fertilizer produced via Jinmei Hengsheng Chemical Co., Ltd., in Xuzhou City, Jiangsu Province, China, was selected as the experimental fertilizer granules. As shown in Figure 11, a prototype of the optimized spiral-pushing fertilizer applicator (OSPFA) and the traditional spiral fertilizer applicator (TSFA) were processed using 3D rapid printing technology, and comparative experiments were conducted in the Intelligent Agricultural Machinery Equipment Engineering Laboratory of Harbin Cambridge University for verification. The rotational speed of the spiral blade was set to 30, 60, 90, 120, 150, 180, and 210 r/min, and the forward speed of the conveyor belt was set to 0.1 m/s. Selecting the fertilizer discharge flow rate as the experimental indicator, the quality of fertilizer in the fertilizer box was measured using a Japanese GX-8K electronic scale. After the spiral-pushing fertilizer applicator stabilizes the fertilizer discharge, we collected the number of fertilizer boxes within a distance range of five seconds of the conveyor belt, calculated their average fertilizer discharge flow rate per second, and repeated the experiment three times to take their average. The experimental results are shown in Figure 12.  
Figure 11: Bench verification test: 1. Fertilizer collection box, 2. Conveyor belt, 3. Spiral-pushing fertilizer applicator, 4. Spiral blade, 5. Drive motor, 6. Rotational speed controller, 7. Fertilizer box, 8. Fertilizer particles. Figure 10: Parameter optimization results. The results from Figure 12 show that the fitting function equation of the fertilizer discharge flow rate of the spiral-pushing fertilizer applicator is \(y=0.486x+1.7417\), and \(R^{2}\) is 0.99. The fitting function equation for the discharge flow rate of a traditional spiral fertilizer applicator is \(y=0.204x-2.227\), and \(R^{2}\) is 0.98. This proves that the linear relationship between the changing trend in the fertilizer discharge flow rate of the spiral-pushing fertilizer applicator is better, and the fitting effect is better than that of the traditional screw fertilizer applicator. Thus, it can precisely adjust its fertilizer discharge flow rate by adjusting the rotational speed. To achieve the design goal of automatically and accurately adjusting the rotational speed according to the fertilizer demand of crops to adjust the spiral-pushing fertilizer applicator fertilizer discharge flow rate, this article designs an electrically controlled fertilizer discharge system with a built-in driving function based on the fertilizer discharge flow equation \(y=0.486x+1.7417\). When the fertilizer demand of crops changes, the rotation speed of the spiral-pushing fertilizer applicator can vary according to the change in fertilizer demand. To verify the fertilizer discharge performance of the electrically controlled fertilizer discharge system, as shown in Figure 13, the electrically controlled fertilizer discharge system was verified in bench tests. We then repeated the experiment thrice at rotational speeds of 37, 49, 85, 134, 161, 179, and 205 r/min, and took the average as the test result. We then compared the results with the preset fertilizer discharge flow rate, as shown in Figure 14. Analysis shows that the average deviation between the spiral-pushing fertilizer applicator controlled is implemented through an electrically controlled fertilizer discharge system. The preset value is 2.14%, which meets the design requirements. Figure 12: Comparison chart of fertilizer discharge flow rate. Figure 13: Verification test of electric control spiral-pushing fertilizer applicator on the bench: 1.