Abstract:Aiming at the agronomic demand for synergistic subsoiling and deep fertilization during the intertillage period in soybean?corn strip intercropping, a subsoiling pneumatic deep fertilization device was designed. By integrating a pneumatic fertilizer delivery system behind the subsoiling shovel, simultaneous soil loosening and deep fertilizer application were achieved. The computational fluid dynamics and discrete element method (CFD?DEM) coupling simulation was used to optimize the structure of air?fertilizer mixing chamber. With the throat contraction depth, throat contraction angle, and transition pipe half?cone angle as influencing factors, and the airflow velocity and fertilizer particle velocity at the fertilizer outlet as test indicators, a regression model between the test indicators and influencing factors was established. The optimized parameters were as follows: throat contraction depth of 28.08 mm, throat contraction angle of 52.1°, and transition pipe half?cone angle of 22.3°. The model predicted an outlet airflow velocity of 16.59 m/s and a fertilizer particle velocity of 2.69 m/s, with a simulation verification error of less than 1.5%. Field test results showed that the designed subsoiling pneumatic deep fertilization device could achieve precise and stable deep fertilizer application, with an average fertilization deviation of 4.63%. The fertilizer discharge consistency among all pipelines was good without clogging. Both subsoiling and fertilization depths met agronomic requirements. The stability coefficients of subsoiling depth for soybean and corn rows were above 96%, and those for fertilization depth were above 95%. The research result can provide an effective equipment solution and theoretical basis for efficient and precise subsoiling and fertilization in soybean?corn intercropping systems.
