Nursery trays are essential agricultural tools in rice production. Plastic nursery trays pose problems such as resource waste and environmental pollution. Biomass seedling trays are an effective way to achieve sustainable agricultural development. Previous research has been conducted on biomass seedling tray molding equipment and molding process, but the impact of raw material ratio on seedling tray molding quality and seedling growth is still unclear, and the ratio combination still needs further optimization. In this study, we used slurry concentration, pulp content, adhesive content, and the ratio of straw to cow manure as variables. We selected the bowl hole molding rate and the strong seedling index as evaluation indicators, and carried out biomass seedling tray forming experiments and seedling cultivation experiments. The response surface analysis method was used to optimize the raw material ratio of biomass seedling trays from the perspectives of forming effect and seedling quality. The results show that when the slurry concentration is 30%, the pulp content is 20%, the adhesive content is 530 g, and the mass ratio of straw to cow manure is 2:1; the bowl hole molding rate is 91.03%, and the strong seedling index is 0.22, indicating good molding effect and seedling growth. The verification test results indicate that the theoretical analysis results are accurate, and the model fitting is good. These research results provide a theoretical basis for the preparation of biomass seedling trays and technical support for achieving green development in agriculture.

In order to solve the problems of existing spiral fertilizer apparatuses, such as the variation in cavity filling rate with rotational speed, fluctuation of fertilizer discharge flow, and inability to discharge fertilizer precisely, a triple-head gradually reducing spiral fertilizer apparatus is designed, which gradually compresses fertilizer particles through the triple-head reducing fertilizer spiral structure to achieve complete cavity filling and uniform fertilizer discharge. The main factors that affect the particle motion state and the structural size of the spiral fertilizer through theoretical analysis are determined, and its theoretical fertilizer discharge amount and rotational speed are calculated. Using EDEM (Discrete Element Method Software 2022) to establish a simulation model of a single-head gradually reducing fertilizer apparatus, the spiral lead reduction percentage x₁, spiral diameter reduction percentage x₂, and rotational speed x₃ are determined as experimental factors, and the filling rate μ and spiral torque Y_average are used as experimental indicators to conduct a simulation study on the secondary universal rotation combination design experiment. The results show that when the rotational speed is 95 r/min, the spiral lead reduction percentage is 60.00~73.21%, the spiral diameter reduction percentage is 86.55~97.05%, the filling rate μ is greater than 95%, and the spiral torque Y_average is less than 16 N·m. In order to further improve the uniformity of fertilizer discharge and ensure the controllable accuracy of fertilizer discharge, comparative verification experiments are conducted on single-, double-, and triple-head gradually reducing spiral fertilizer discharge devices and ordinary spiral fertilizer discharge devices. The results show that the precision of the gradually reducing spiral fertilizer apparatus is better than that of the ordinary spiral fertilizer apparatus. Moreover, it is determined that the three-head style performed best. The triple-head gradually reducing spiral fertilizer apparatus is also validated by randomly adjusting six rotational speeds. The experiment results show that the average deviation of the fertilizer discharge flow rate of the fertilizer apparatus from the preset value is 3.16%. The two have a minor deviation, and the fertilizer precision is high. Precise control of the amount of fertilizer discharged can be achieved by adjusting the rotational speed, and the research can provide a specific reference for the improved design and precise control of the spiral fertilizer apparatus.

In major pineapple-producing regions of China, conventional manual harvesting is challenged by high labor intensity and cost. Existing mechanical harvesters, still largely in the research and development stage, often suffer from low efficiency and high susceptibility to fruit damage, failing to meet large-scale production demands. This study focuses on the Tainung 16 pineapple, determining that the tensile force required to separate the fruit stem at the calyx ranges from 100.42 N to 165.38 N. Drawing on the biomimetic principles of manual stem-breaking, we designed a harvesting device featuring a curved fixed baffle and a rotating unit. Using theoretical analysis and ADAMS simulation, a mechanical model of the device–stem interaction was established to simulate the force application, bending, and separation processes. This led to the identification of optimal operational parameters: a forward speed of 1.5 m/s, a harvesting unit rotational speed of 37 r/min, and a motion trajectory parameter of 1.3. Field tests demonstrated an average harvesting success rate of 81.23% with a fruit damage rate as low as 9.35%. The device thus effectively addresses the critical industry challenges of low efficiency and high damage. This work provides a direct technical reference and theoretical foundation for the engineering development, refinement, and standardized field operation of pineapple harvesters, facilitating the transition to mechanized large-scale harvesting.