To avoid the issues of undesired soil compaction and seeding depth variation caused by the downforce fluctuation of the corn no-till planter, the influence of the structural parameters of the air spring on the downforce was researched in this paper, by establishing the gas–solid coupling simulation model of the air spring. The downforce test bench was built to verify the simulation model; the test showed that the vertical output force error of the simulation model was 4.79%, the pitch diameter error was 0.76%, and the pressure error was 5.07%. The cord angle, piston angle and piston diameter were used as influencing factors to carry out single-factor experiments. The influences of structural parameters on downforce were analyzed from four aspects: the vertical output force, the vertical stiffness, the pressure difference and the deformation rate. The results showed that the cord angle reduced the effective area and its change rate during deformation by limiting the radial deformation of the bellow. When the cord angles were 30°, 45° and 60°, the deformation rates were 65.6%, 20.3% and 4.8%, respectively. The cord angle had a positive effect on the vertical output force when the cord angle was in the range of 30~56°, and it had a negative impact in the range of 56~60°. As the cord angle increased, the vertical stiffness decreased. As the piston angle increased, the effective area of the air spring decreased, and the change in internal pressure decreased, reducing its vertical output force and stiffness. The piston diameter had little effect on the internal pressure and deformation rate. It increased the vertical output force and stiffness by increasing the effective area. The structural parameters of the air spring had a significant impact on the stability of the downforce; the structure of the air spring should be optimized according to the downforce demand of the corn no-till planter.

Focusing on the problems of the poor filling ability and stability of the mechanical wheat seeder and the complicated structure of the pneumatic seeder, a special air suction wheel-hole single seed drill for remote controlled self-propelled single seed dibbler in wheat plots was designed in this paper. According to the agronomic requirements of precision seeding in wheat plots, the seeding wheel radius was set at 180 mm 16 suction holes. Using the discrete element simulation software EDEM to analyze the seed disturbance effect of different parameter designs, the thickness of seed suction ring was 16 mm, the height of seed suction mouth was 4.5 mm, and the diameter of seed suction cam was 12 mm. Through hydrodynamic simulation, the phase angle of the negative pressure chamber was 280 degrees, positive pressure chamber was 22 degrees, phase angle of the unpressurized interval zone was 20 degrees, thickness of the negative pressure chamber was 24.5 mm, diameter of transition pipe was 17.5 mm and length of the transition pipe was 14.5 mm. Based on the above design parameters, the samples were then processed and benchtop experiments carried out. The results showed that under the best operating parameters, the re-suction index was 0.82%, the leakage index was 6.67%, and the qualified index was 92.41%, which met the design requirements. This study could provide a reference for the design of single-seed dibbling technology in wheat plots.

At present, liquid starter fertilizer (LSF) application technologies experience problems with low fertilizer utilization efficiency. In this study, we adopted a method of precise application of LSF near the seeds on seed bed in point form during sowing. A precise application system that can detect seed information in real time and control the solenoid valve to open automatically was developed for this method. The LSF supply system and detection control system were studied in detail. Field experiments were conducted to evaluate the performance of the precise application system in terms of operation quality (qualified index of the length of the LSF, QIL; the amount of the LSF, FA; and qualified index of the distance between the seeds and the LSF, QID) at forward speeds of 4, 6, and 8 km/h and pressures of 0.10, 0.15, 0.20, 0.25, and 0.30 MPa. The results indicated that QIL was 96.4%, the range of FA was 1.34 to 13.86 mL, and QID was 82.6%, which signifies the developed system meets the demands of precise LSF application. This method achieves the target of improving fertilizer use efficiency and provides a reference for developing fertilization devices for precisely applying LSF.

In order to explore the beneficial effects of conservation tillage (straw burial, stubble + straw mulching, straw mulching) compared with traditional tillage on suppressing farmland dust and the law on farmland wind erosion, PM2.5 and PM10, in this study, according to the distribution characteristics of farmland dust particles “from large to small” and “from bottom to top”, the self-designed dust collector and farmland dust online monitoring system were used to analyze the amount of wind and dust, PM2.5 and PM10, near the surface of farmland. A comparative study on the dust emission of farmland from conservation tillage and traditional tillage is conducted in two dimensions. The mobile wind tunnels are used to simulate and verify the release of PM2.5 and PM10 near the surface of farmland. Among them, the monitoring of farmland wind erosion shows that compared with traditional farming, the wind erosion of straw burial, stubble + straw mulching, and straw mulching decreased by 29.37%, 40.73%, and 36.61%, respectively, and 90~250 μm large-size sand particles are reduced by 37.2%, 74.7%, and 31.6%, respectively. The monitoring results of PM2.5 and PM10 near the surface of the farmland showed that the stubble + straw mulching model is compared with the traditional farming farmland. The reductions were 42.5% and 40.8%, significantly higher than the straw burial and straw mulching modes. The multiple linear regression analysis of the monitoring data showed that the PM2.5 and PM10 release concentrations near the surface of farmland had the highest correlation with wind speed, followed by soil moisture and temperature. Wind tunnel test verification shows that the following three protective tillage modes: straw burial, straw mulching, and stubble + straw mulching, have apparent inhibitory effects on PM2.5 and PM10 released on farmland compared with traditional tillage modes. In 1~8 m/s interval, the release concentration of PM2.5 in the modes of straw burial, stubble + straw mulching, and straw mulching decreased by 15.34~41.17%, 32.05~48.56%, and 28.85~42.40%, and the PM10 release concentration decreased by 19.44~36.47%, 35.90~52.00%, and 25.83~50.63%, respectively, which are consistent with the monitoring results of PM2.5 and PM10 near the surface of farmland. The research results show that the beneficial effects of each model on farmland dust suppression are stubble + straw mulching > straw mulching > straw burial. The study is intended to provide theoretical support for promoting conservation tillage and the return of high-quality straw mulch to the field in Beijing.

Design and experiment of pneumatic pressure control device for no-till planter