In order to improve the surface wear resistance of the key parts of agricultural machinery, this article uses 65Mn steel, which is commonly used in agricultural machinery, as the matrix and tungsten carbide-based coating as the basis. In total, two coating materials are selected as WC-10Co-4Cr with and without CeO₂ added. The coating was prepared by the supersonic flame spraying process (HVOF), and the tribological characteristics and coating of the three samples of 65Mn, WC-10Co-4Cr, and WC-10Co-4Cr+CeO₂ coatings were investigated by the comprehensive material surface performance tester. Layer porosity, microhardness, and X-ray powder diffraction (XRD) phase analysis reveal the modification mechanism of WC-10Co-4Cr coating by rare earth CeO₂. The experimental comparison results show that WC-10Co-4Cr is prepared on the 65Mn steel substrate, and the WC-10Co-4Cr+CeO₂ coating significantly improves the surface hardness, the coating structure is uniform and dense, and the pores are less. The coating hardness value is relatively high, reaching 1200–1500 HV(N/mm²), and the porosity is less than 1%. When the rare earth cerium oxide is added to WC-10Co-4Cr, the porosity of the coating decreases and the hardness increases. It is proved that rare earth has the modification effect of refining the coating structure. Therefore, adding CeO₂ to the WC-10Co-4Cr coating and using the supersonic flame spraying process to prepare the coating can obtain more excellent wear resistance.

The feeder, a critical component of pneumatic conveying and distributing fertilizer machines for cotton, significantly impacts cotton quality and yield. This study addresses the limitations of conventional feeders, namely poor delivery stability and insufficient air–fertilizer mixture uniformity, by introducing a novel feeder design incorporating guide-flow chamber vanes. Based on the structural principles of pneumatic fertilizer distribution and the theory of vortex flow feeding, the new feeder design was developed and analyzed using a CFD-DEM coupled model to simulate its operational process. Response surface methodology was employed to optimize key structural parameters, aiming to enhance both air–fertilizer mixture uniformity and fertilizer delivery stability. The optimized design features two guide vanes, a fertilizer discharge contraction angle of 23.2°, and eight chamber lines. Validation through simulation confirmed the model’s reliability, with a discrepancy of less than 5% between simulated and predicted values. Experimental validation on a pneumatic fertilizing test prototype further demonstrated the effectiveness of the optimization, resulting in a feeder stability coefficient of variation of 13.30% and a coefficient of variation in fertilizer distribution across the system’s branches of 3.96%, satisfying practical operational requirements. After optimization, the stability and uniformity of the feeder fertilizer are significantly improved. The optimized feeder design effectively improves the stability and air–fertilizer mixing uniformity of cotton pneumatic fertilizing machines, providing valuable theoretical and technical support for their design optimization and performance enhancement.

Aiming to address the problems of low flow-control accuracy, slow response speed, and difficulties in remote monitoring during precision agricultural fertilization, this study proposes a fertilization flow control method based on the tuna swarm optimization algorithm (TSO) combined with fuzzy PID control. Remote monitoring and cloud-based management of the system are achieved through the MQTT protocol. The proposed method uses the TSO to globally optimize the initial PID parameters and the outputs of fuzzy rules, while fuzzy logic is employed to realize real-time adaptive adjustment of control parameters under nonlinear operating conditions. The experimental results show that the proposed TSO-Fuzzy-PID controller exhibits excellent dynamic performance in fertilization flow control. Compared with the conventional PID controller, the maximum overshoot of the system is reduced from 28.37% to 9.15%, and the settling time is shortened from 111 s to 76 s. The remote communication test results indicate that, during 20 consecutive tests lasting 60 min each, the average communication delay of the MQTT communication link remains within 162–215 ms, the maximum delay does not exceed 300 ms, and the message transmission success rate reaches 99.4%, verifying the good real-time performance and reliability of the system.